Yunqi Liu

Aggregation greatly boosts emission efficiency of the silole, turning it from a weak luminophor into a strong emitter.

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTSemiconducting π-Conjugated Systems in Field-Effect Transistors: A Material Odyssey of Organic ElectronicsChengliang Wang, Huanli Dong, Wenping Hu*, Yunqi Liu, and Daoben ZhuView Author Information Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China*Address: Zhongguancun North First No 2, Beijing, 100190, China. E-mail: [email protected]Cite this: Chem. Rev. 2012, 112, 4, 2208–2267Publication Date (Web):November 23, 2011Publication History Received15 November 2010Published online23 November 2011Published inissue 11 April 2012https://doi.org/10.1021/cr100380zCopyright © 2011 American Chemical SocietyRequest reuse permissionsArticle Views41831Altmetric-Citations3014LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (15 MB) Get e-AlertscloseSUBJECTS:Aromatic compounds,Hydrocarbons,Mobility,Reaction products,Thin films Get e-Alerts

To realize graphene-based electronics, various types of graphene are required; thus, modulation of its electrical properties is of great importance. Theoretic studies show that intentional doping is a promising route for this goal, and the doped graphene might promise fascinating properties and widespread applications. However, there is no experimental example and electrical testing of the substitutionally doped graphene up to date. Here, we synthesize the N-doped graphene by a chemical vapor deposition (CVD) method. We find that most of them are few-layer graphene, although single-layer graphene can be occasionally detected. As doping accompanies with the recombination of carbon atoms into graphene in the CVD process, N atoms can be substitutionally doped into the graphene lattice, which is hard to realize by other synthetic methods. Electrical measurements show that the N-doped graphene exhibits an n-type behavior, indicating substitutional doping can effectively modulate the electrical properties of graphene. Our finding provides a new experimental instance of graphene and would promote the research and applications of graphene.

The construction of highly active and stable non-noble-metal electrocatalysts for hydrogen and oxygen evolution reactions is a major challenge for overall water splitting. Herein, we report a novel hybrid nanostructure with CoP nanoparticles (NPs) embedded in a N-doped carbon nanotube hollow polyhedron (NCNHP) through a pyrolysis-oxidation-phosphidation strategy derived from core-shell ZIF-8@ZIF-67. Benefiting from the synergistic effects between highly active CoP NPs and NCNHP, the CoP/NCNHP hybrid exhibited outstanding bifunctional electrocatalytic performances. When the CoP/NCNHP was employed as both the anode and cathode for overall water splitting, a potential as low as 1.64 V was needed to achieve the current density of 10 mA·cm-2, and it still exhibited superior activity after continuously working for 36 h with nearly negligible decay in potential. Density functional theory calculations indicated that the electron transfer from NCNHP to CoP could increase the electronic states of the Co d-orbital around the Fermi level, which could increase the binding strength with H and therefore improve the electrocatalytic performance. The strong stability is attributed to high oxidation resistance of the CoP surface protected by the NCNHP.

Recently, a lot of effort has been focused on improving the performance and exploring the electric properties of graphene. This article presents a summary of chemical doping of graphene aimed at tuning the electronic properties of graphene. p-Type and n-type doping of graphene achieved through surface transfer doping or substitutional doping and their applications based on doping are reviewed. Chemical doping for band gap tuning in graphene is also presented. It will be beneficial to designing high performance electronic devices based on chemically doped graphene.

We develop an N-coordination strategy to design a robust CO2 reduction reaction (CO2RR) electrocatalyst with atomically dispersed Co–N5 site anchored on polymer-derived hollow N-doped porous carbon spheres. Our catalyst exhibits high selectivity for CO2RR with CO Faradaic efficiency (FECO) above 90% over a wide potential range from −0.57 to −0.88 V (the FECO exceeded 99% at −0.73 and −0.79 V). The CO current density and FECO remained nearly unchanged after electrolyzing 10 h, revealing remarkable stability. Experiments and density functional theory calculations demonstrate single-atom Co–N5 site is the dominating active center simultaneously for CO2 activation, the rapid formation of key intermediate COOH* as well as the desorption of CO.

Microelectronic circuits/arrays produced via high-speed printing instead of traditional photolithographic processes offer an appealing approach to creating the long-sought after, low-cost, large-area flexible electronics. Foremost among critical enablers to propel this paradigm shift in manufacturing is a stable, solution-processable, high-performance semiconductor for printing functionally capable thin-film transistors - fundamental building blocks of microelectronics. We report herein the processing and optimisation of solution-processable polymer semiconductors for thin-film transistors, demonstrating very high field-effect mobility, high on/off ratio, and excellent shelf-life and operating stabilities under ambient conditions. Exceptionally high-gain inverters and functional ring oscillator devices on flexible substrates have been demonstrated. This optimised polymer semiconductor represents a significant progress in semiconductor development, dispelling prevalent skepticism surrounding practical usability of organic semiconductors for high-performance microelectronic devices, opening up application opportunities hitherto functionally or economically inaccessible with silicon technologies, and providing an excellent structural framework for fundamental studies of charge transport in organic systems.

Two donor–acceptor (D−A) copolymer PDVTs based on diketopyrrolopyrole and (E)-2-(2-(thiophen-2-yl)vinyl)thiophene (TVT) units are synthesized for solution-processed field-effect transistors (FETs). The highly π-extended TVT units strengthen the coplanarity of the polymer backbone. FETs based on PDVTs show high mobilities above 2.0 cm2 V−1 s−1 with a current on/off ratio of 105−107, high shelf storage, and operation stability.

Pi-conjugated molecular materials with fused rings are the focus of considerable interest in the emerging area of organic electronics, since the combination of excellent charge carrier mobility and high stability may lead to their practical applications. This tutorial review discusses the synthesis, properties and applications of pi-conjugated organic semiconducting materials, especially those with fused rings. The achievements to date, the remaining problems and challenges, and the key research that needs to be done in the near future are all discussed.

Abstract The advantages of organic field‐effect transistors, such as low cost, mechanical flexibility and large‐area fabrication, make them potentially useful for electronic applications such as flexible switching backplanes for video displays, radio frequency identifications and so on. A large amount of molecules were designed and synthesized for electron transporting (n‐type) and ambipolar organic semiconductors with improved performance and stability. In this review, we focus on the advances in performance and molecular design of n‐type and ambipolar semiconductors reported in the past few years.

2,3,4,5-Tetraphenylsiloles with different 1,1-substituents on the ring silicon atoms, i.e., 1,1-dimethyl-2,3,4,5-tetraphenylsilole (1), 1-methyl-1-(3-chloropropyl)-2,3,4,5-tetraphenylsilole (2), 1-methyl-1,2,3,4,5-pentaphenylsilole (3) and hexaphenylsilole (4), are synthesized and characterized. While all the siloles emit intense blue light readily observable by naked eyes under normal room illumination conditions, the film of their acyclic cousin without silicon, namely 1,2,3,4-tetraphenylbutadiene (5), does not fluoresce, revealing the vital role of the planar and rigid silacyclopentadiene ring in the solid-state photoluminescence process. The electronic transitions of the siloles can be tuned by varying the 1,1-substituents, and the inductive and conjugating effects of the aromatic rings confer low LUMO energy levels and high emission efficiencies on the phenyl-substituted siloles. The electroluminescence device of the 1-phenylsilole 3 shows a high brightness (4538 cd m−2 at 18 V) and an excellent external quantum efficiency (0.65% at 17 V and 94 mA cm−2).

Monodispersed nickel phosphide nanocrystals (NCs) with different phases were successfully synthesized. The Ni₅P₄ NCs, with a solid structure, exhibited higher catalytic activity than the Ni₁₂P₅ and Ni₂P NCs.

Abstract Functional organic field‐effect transistors (OFETs) have attracted increasing attention in the past few years due to their wide variety of potential applications. Research on functional OFETs underpins future advances in organic electronics. In this review, different types of functional OFETs including organic phototransistors, organic memory FETs, organic light emitting FETs, sensors based on OFETs and other functional OFETs are introduced. In order to provide a comprehensive overview of this field, the history, current status of research, main challenges and prospects for functional OFETs are all discussed

The excellent electroluminescent (EL) properties of 1,1-disubstituted 2,3,4,5-tetraphenylsiloles, 1-methyl-1,2,3,4,5-pentaphenylsilole (MPPS), and 1,1,2,3,4,5-hexaphenylsilole (HPS) have been found. Despite some studies devoted to these materials, very little is known about the real origin of their unique EL properties. Therefore, we investigated the structures, photoluminescence (PL), and charge carrier transport properties of 1,1-disubstituted 2,3,4,5-tetraphenylsiloles as well as the effect of substituents on these characteristics. The single crystals of the three siloles involving 1,1-dimethyl-2,3,4,5-tetraphenylsilole (DMTPS), MPPS, and HPS were grown and their crystal structures were determined by X-ray diffraction. Three siloles have nonplanar molecular structures. The substituents at 1,1-positions enhance the steric hindrance and have predominant influence on the twisted degree of phenyl groups at ring carbons. This nonplanar structure reduces the intermolecular interaction and the likelihood of excimer formation, and increases PL efficiency in the solid state. The silole films show high fluorescence quantum yields (75−85%), whereas their dilute solutions exhibit a faint emission. The electronic structures of the three siloles were investigated using quantum chemical calculations. The highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs) are mainly localized on the silole ring and two phenyl groups at 2,5-positions in all cases, while the LUMOs have a significant orbital density at two exocyclic Si−C bonds. The extremely theoretical studies of luminescent properties were carried out. We calculated the nonradiative decay rate of the first excited state as well as the radiative one. It is found that the faint emission of DMTPS in solutions mainly results from the huge nonradiative decay rate. In solid states, molecular packing can remarkably restrict the intramolecular rotation of the peripheral side phenyl ring, which has a large contribution to the nonradiative transition process. This explains why the 1,1-disubstituted 2,3,4,5-tetraphenylsiloles in the thin films exhibit high fluorescence quantum yields. The charge carrier mobilities of the MPPS and HPS films were measured using a transient EL technique. We obtained a mobility of 2.1 × 10-6 cm2/V·s in the MPPS film at an electric field of 1.2 × 106 V/cm. This mobility is comparable to that of Alq3, which is one of the most extensively used electron transport materials in organic light-emitting diodes (LEDs), at the same electric field. The electron mobility of the HPS film is about ∼1.5 times higher than that of the MPPS film. To the best of our knowledge, this kind of material is one of the most excellent emissive materials that possess both high charge carrier mobility and high PL efficiency in the solid states simultaneously. The excellent EL performances of MPPS and HPS are presumably ascribed to these characteristics.

Abstract Developing an efficient single‐atom material (SAM) synthesis and exploring the energy‐related catalytic reaction are important but still challenging. A polymerization–pyrolysis–evaporation (PPE) strategy was developed to synthesize N‐doped porous carbon (NPC) with anchored atomically dispersed Fe‐N 4 catalytic sites. This material was derived from predesigned bimetallic Zn/Fe polyphthalocyanine. Experiments and calculations demonstrate the formed Fe‐N 4 site exhibits superior trifunctional electrocatalytic performance for oxygen reduction, oxygen evolution, and hydrogen evolution reactions. In overall water splitting and rechargeable Zn–air battery devices containing the Fe‐N 4 SAs/NPC catalyst, it exhibits high efficiency and extraordinary stability. This current PPE method is a general strategy for preparing M SAs/NPC (M=Co, Ni, Mn), bringing new perspectives for designing various SAMs for catalytic application.

A highly efficient acceptor material for organic solar cells (OSCs) – based on perylene diimide (PDI) dimers – shows significantly reduced aggregation compared to monomeric PDI. The dimeric PDI shows a best power conversion efficiency (PCE) approximately 300 times that of the monomeric PDI when blended with a conjugate polymer (BDTTTT-C-T) and with 1,8-diiodooctane as co-solvent (5%). This shows that non-fullerene materials also hold promise for efficient OSCs. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

The practical application of hydrogen evolution reaction (HER) through water splitting depends on the development of low cost and efficient non-noble-metal catalysts. As a potential electrocatalyst, the improvement of HER performance catalyzed by nanostructured transition metal phosphides still remains a great challenge. Tuning the novel nanostructure, morphology, and electronic state from nanoscale is of great important to achieve highly efficient HER electrocatalysts. Herein, we first developed an electronic structure and d-band center control engineering for accelerating the HER process in both acid and alkaline media over M-doped CoP (M = Ni, Mn, Fe) hollow polyhedron frames (HPFs), which were synthesized by a self-templating transformation (STT) strategy. Impressively, the HER electrocatalytic activity can be maximumly promoted and maintained at least 21 h for Ni-CoP/HPFs catalyst. Synchrotron-based X-ray absorption near-edge structure, X-ray photoelectron spectroscopy, auger electron spectroscopy, ultraviolet photoemission spectroscopy and density functional theory calculations consistently reveal the improved performance is attributed to the changes of the electronic structure and the downshift of d-band center after metal doping. The Ni-CoP/HPFs catalyst also indicates excellent activity with a cell voltage of 1.43 V to achieve the current density of 10 mA cm−2 and superior stability when it was employed as a cathode for HER and an anode for urea oxidation in 1 M KOH with 0.5 M urea. The success modulation of HER performance in current STT strategy will provide a promising pathway for designing various transition metal-doped compounds for energy-related catalysis processes.

Unresolved problems associated with the production of graphene materials include the need for greater control over layer number, crystallinity, size, edge structure and spatial orientation, and a better understanding of the underlying mechanisms. Here we report a chemical vapor deposition approach that allows the direct synthesis of uniform single-layered, large-size (up to 10,000 μm 2 ), spatially self-aligned, and single-crystalline hexagonal graphene flakes (HGFs) and their continuous films on liquid Cu surfaces. Employing a liquid Cu surface completely eliminates the grain boundaries in solid polycrystalline Cu, resulting in a uniform nucleation distribution and low graphene nucleation density, but also enables self-assembly of HGFs into compact and ordered structures. These HGFs show an average two-dimensional resistivity of 609 ± 200 Ω and saturation current density of 0.96 ± 0.15 mA/μm, demonstrating their good conductivity and capability for carrying high current density.

Photoluminescence of simple arylbenzenes with ready synthetic accessibility is enhanced by two orders of magnitude through aggregate formation; viscosity and temperature effects indicate that the emission enhancement is due to the restriction of their intramolecular rotations in the solid state.

Since organic field-effect transistors (OFETs) were first described in 1987, they have undergone great progress, especially in the last several years. Nowadays, the performance of OFETs is similar to that of amorphous silicon (a-Si : H) devices and they have become one of the most important components of organic electronics. This feature article introduces briefly the operating principles, fabrication techniques of the transistors, and in particular highlights the recent progress, not only including materials and fabrication techniques, but also involving organic single crystal FETs and organic light-emitting FETs, which have been reported recently. Finally, the prospects and problems of OFETs that exist are discussed.

We reported the development of a new type of multifunctional titanium dioxide (TiO2)-graphene nanocomposite hydrogel (TGH) by a facile one-pot hydrothermal approach and explored its environmental and energy applications as photocatalyst, reusable adsorbents, and supercapacitor. During the hydrothermal reaction, the graphene nanosheets and TiO2 nanoparticles self-assembled into three-dimensional (3D) interconnected networks, in which the spherical nanostructured TiO2 nanoparticles with uniform size were densely anchored onto the graphene nanosheets. We have shown that the resultant TGH displayed the synergistic effects of the assembled graphene nanosheets and TiO2 nanoparticles and therefore exhibited a unique collection of physical and chemical properties such as increased adsorption capacities, enhanced photocatalytic activities, and improved electrochemical capacitive performance in comparison with pristine graphene hydrogel and TiO2 nanoparticles. These features collectively demonstrated the potential of 3D TGH as an attractive macroscopic device for versatile applications in environmental and energy storage issues.

The exploration of highly active and stable noble-metal-free electrocatalysts for hydrogen and oxygen evolution reaction is a challenging task to achieve sustainable production of H2 through water splitting. Herein, we present the design and synthesis of a novel three-dimensional(3D)-networked heterogeneous nickel phosphide/sulfide electrocatalyst consisting of Ni2P strongly coupled with Ni3S2 in situ grown on Ni foam. Benefiting from the strong interfacial coupling effects between Ni2P and Ni3S2, large surface area, highly conductive Ni foam support, and the unique 3D open configuration, the optimal 3D-networked hybrid electrode exhibits superior electrocatalytic activity with extremely low overpotentials of 80 and 210 mV to deliver a current density of 10 mA cm−2 for HER and OER in 1.0 M KOH, respectively. Assembled as an electrolyzer for overall water splitting, this electrode delivers an impressive low onset potential of only 1.45 V and gives a current density of 10 mA cm−2 at a very low cell voltage of 1.50 V, which is dramatically superior to the current state-of-the-art electrocatalysts. In combination with density functional theory (DFT) calculations, this study demonstrates that the strong coupling interactions between Ni2P and Ni3S2 synergistically optimize the electronic structure and tune the hydrogen (or water) adsorption energy, thus significantly enhancing the overall electrochemical water-splitting activity. Our work might shed some new lights on the design and fabrication of efficient and robust three-dimensional hybrid electrode materials for a variety of electrochemical applications.

Abstract Graphene, a two‐dimensional material, is regarded as one of the most promising candidates for future nanoelectronics due to its atomic thickness, excellent properties and widespread applications. As the first step to investigate its properties and finally to realize the practical applications, graphene must be synthesized in a controllable manner. Thus, controllable synthesis is of great significance, and received more and more attention recently. This Progress Report highlights recent advances in controllable synthesis of graphene, clarifies the problems, and prospects the future development in this field. The applications of the controllable synthesis are also discussed.

Organic semiconductors have attracted wide attention in recent decades, resulting in the rapid development of organic electronics. For example, the solution processibility of organic semiconductors allows researchers to use unconventional deposition methods (such as inkjet printing and stamping) to fabricate large area devices at low cost. The mechanical properties of organic semiconductors also allow for flexible electronics. However, the most distinguishing feature of organic semiconductors is their chemical versatility, which permits the incorporation of functionalities through molecular design. However, key scientific challenges remain before organic electronics technology can advance further, including both the materials' low charge carrier mobility and researchers' limited knowledge of structure-property relationships in organic semiconductors. We expect that high-quality organic single crystals could overcome these challenges: their purity and long-range ordered molecular packing ensure high device performance and facilitate the study of structure-property relationships. Micro- and nanoscale organic crystals could offer practical advantages compared with their larger counterparts. First, growing small crystals conserves materials and saves time. Second, devices based on the smaller crystals could maintain the functional advantages of larger organic single crystals but would avoid the growth of large crystals, leading to the more efficient characterization of organic semiconductors. Third, the effective use of small crystals could allow researchers to integrate these materials into micro- and nanoelectronic devices using a "bottom-up" approach. Finally, unique properties of crystals at micro- and nanometer scale lead to new applications, such as flexible electronics. In this Account, we focus on organic micro- and nanocrystals, including their design, the controllable growth of crystals, and structure-property studies. We have also fabricated devices and circuits based on these crystals. This interdisciplinary work combines techniques from the fields of synthetic chemistry, self-assembly, crystallography, and condensed matter physics. We have designed new molecules, including a macrocycle and polyaromatic compounds that self-assemble in a predictive manner into regular high-quality crystals. We have examined how the structure, particularly pi-pi interactions, determines the crystal growth and how the external conditions affect the crystal morphology. We have developed new methods, such as the gold wire mask, the organic ribbon mask, and the gold layer stamp techniques, to fabricate high-performance devices based on the small crystals and investigate their anisotropic charge transport properties. In addition, we have demonstrated small-crystal organic circuits that function with high performance and ultralow power consumption. We expect that organic micro- and nanocrystals have a bright future in organic electronics.

The integration of graphene nanosheets on the macroscopic level using a self‐assembly method has been recognized as one of the most effective strategies to realize the practical applications of graphene materials. Here, a facile and scalable method is developed to synthesis two types of graphene‐based networks, manganese dioxide (MnO 2 )–graphene foam and carbon nanotube (CNT)–graphene foam, by solution casting and subsequent electrochemical methods. Their practical applications in flexible all‐solid‐state asymmetric supercapacitors are explored. The proposed method facilitates the structural integration of graphene foam and the electroactive material and offers several advantages including simplicity, efficiency, low‐temperature, and low‐cost. The as‐prepared MnO 2 –graphene and CNT–graphene electrodes exhibit high specific capacitances and rate capability. By using polymer gel electrolytes, a flexible all‐solid‐state asymmetric supercapacitor was synthesized with MnO 2 –graphene foam as the positive electrode and CNT‐graphene as the negative electrode. The asymmetric supercapacitors can be cycled reversibly in a high‐voltage region of 0 to 1.8 V and exhibit high energy density, remarkable rate capability, reasonable cycling performance, and excellent flexibility.

Vertical heterojunctions of two two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted considerable attention recently. A variety of heterojunctions can be constructed by stacking different TMDs to form fundamental building blocks in different optoelectronic devices such as photodetectors, solar cells, and light-emitting diodes. However, these applications are significantly hampered by the challenges of large-scale production of van der Waals stacks of atomically thin materials. Here, we demonstrate scalable production of periodic patterns of few-layer WS2, MoS2, and their vertical heterojunction arrays by a thermal reduction sulfurization process. In this method, a two-step chemical vapor deposition approach was developed to effectively prevent the phase mixing of TMDs in an unpredicted manner, thus affording a well-defined interface between WS2 and MoS2 in the vertical dimension. As a result, large-scale, periodic arrays of few-layer WS2, MoS2, and their vertical heterojunctions can be produced with desired size and density. Photodetectors based on the as-produced MoS2/WS2 vertical heterojunction arrays were fabricated, and a high photoresponsivity of 2.3 A·W–1 at an excitation wavelength of 450 nm was demonstrated. Flexible photodetector devices using MoS2/WS2 heterojunction arrays were also demonstrated with reasonable signal/noise ratio. The approach in this work is also applicable to other TMD materials and can open up the possibilities of producing a variety of vertical van der Waals heterojunctions in a large scale toward optoelectronic applications.

Since the report of the first diketopyrrolopyrrole (DPP)‐based polymer semiconductor, such polymers have received considerable attention as a promising candidate for high‐performance polymer semiconductors in organic thin‐film transistors (OTFTs). This Progress Report summarizes the advances in the molecular design of high‐mobility DPP‐based polymers reported in the last few years, especially focusing on the molecular design of these polymers in respect of tuning the backbone and side chains, and discussing the influences of structural modification of the backbone and side chains on the properties and device performance of corresponding DPP‐based polymers. This provides insights for the development of new and high‐mobility polymer semiconductors.

We present the synthesis and characterization of a fused-ring compound, dithieno[2,3-d:2‘,3‘-d‘]thieno[3,2-b:4,5-b‘]dithiophene (pentathienoacene, PTA). In contrast to pentacene, PTA has a larger band gap than most semiconductors used in organic field-effect transistors (OFETs) and therefore is expected to be stable in air. The large π-conjugated and planar molecular structure of PTA would also form higher molecular orders that are conductive for carrier transport. X-ray diffraction and atomic force microscopy experiments on its films show that the molecules stack in layers with their long axis upright from the surface. X-ray photoelectron spectroscopy suggests that there are no chemical bonds at the PTA/Au interface. OFETs based on the PTA have been constructed, and their performances as p-type semiconductors are also presented. A high mobility of 0.045 cm2/V s and an on/off ratio of 103 for a PTA OFET have been achieved, demonstrating the potential of PTA for application in future organic electronics.

Human eyes undertake the majority of information assimilation for learning and memory. Transduction of the color and intensity of the incident light into neural signals is the main process for visual perception. Besides light-sensitive elements that function as rods and cones, artificial retinal systems require neuromorphic devices to transform light stimuli into post-synaptic signals. In terms of plasticity timescale, synapses with short-term plasticity (STP) and long-term potentiation (LTP) represent the neural foundation for experience acquisition and memory formation. Currently, electrochemical transistors are being researched as STP-LTP devices. However, their LTP timescale is confined to a second-to-minute level to give unreliable non-volatile memory. This issue limits multiple-plasticity synapses with tunable temporal characteristics and efficient sensory-memory systems. Herein, a ferroelectric/electrochemical modulated organic synapse is proposed, attaining three prototypes of plasticity: STP/LTP by electrochemical doping/de-doping and ferroelectric-LTP from dipole switching. The device supplements conventional electrochemical transistors with 10000-second-persistent non-volatile plasticity and unique threshold switching properties. As a proof-of-concept for an artificial visual-perception system, an ultraflexible, light-triggered organic neuromorphic device (LOND) is constructed by this synapse. The LOND transduces incident light signals with different frequency, intensity, and wavelength into synaptic signals, both volatile and non-volatile.

Compared with traditional silicon electronics, electronic devices based on organic field-effect transistors (OFETs) offer unique advantages, including mechanical flexibility, solution processability, and tunable optoelectronic properties. During the past several years, impressive advances have been made in OFETs, particularly in conjugated polymer-based FETs. Numerous FETs based on high-performance polymers have been developed thanks to the efforts of material design and device optimization. A remarkable mobility of more than 10 cm2 V−1 s−1 has been achieved in OFETs, which provides a promising opportunity for applications in flexible displays and wearable devices. This review describes the recent progress of this field from four aspects: basic knowledge, material design strategies, solution-processable techniques, and functional applications of OFETs. In addition, the current challenges and future outlook of this field are briefly discussed.

By virtue of their excellent solution processibility and flexibility, organic field-effect transistors (OFETs) are considered outstanding candidates for application in low-cost, flexible electronics. Not only does the performance of OFETs depend on the molecular properties of the organic semiconductors involved, but it is also dramatically affected by the nature of the interfaces present. Therefore, interface engineering, a novel approach towards high-performance OFETs, has attracted considerable attention. In this Account, we focus on recent advances in the study of OFET interfaces—including electrode/organic layer interfaces, dielectric/organic layer interfaces, and organic/organic layer interfaces—that have resulted in improved device performance, enhanced stability, and the realization of organic light-emitting transistors. The electrode/organic layer interface, one of the most important interfaces in OFETs, usually determines the carrier injection characteristics. Focusing on OFETs with copper and silver electrodes, we describe effective modification approaches of the electrode/organic layer interfaces. Furthermore, the influence of electrode morphology on device performance is demonstrated. These results provide novel approaches towards high-performance, low-cost OFETs. The dielectric/organic layer interface is a vital interface that dominates carrier transport; modification of this interface therefore offers a general way to improve carrier transport accordingly. The dielectric layer also affects the device stability of OFETs. For example, high-performance pentacene OFETs with excellent stability are obtained by the selection of a dielectric layer with an appropriate surface energy. The organic/organic layer interface is a newly investigated topic in OFETs. Introduction of organic/organic layer interfaces, such as heterojunctions, can improve device performance and afford ambipolar OFETs. By designing laterally arranged heterojunctions made of organic field-effect materials and light-emitting materials, we realized both light emission and field effects simultaneously in a single OFET. The preceding decade has seen great progress in OFETs. Interface engineering provides a simple but effective approach toward creating high-performance OFETs and will continue to make essential contributions in the development of useful OFET-based devices. The exploration of novel interface engineering applications also merits further attention; the design of gas sensors through a more complete understanding of interface phenomena serves as just one example.

We report the metal-catalyst-free synthesis of high-quality polycrystalline graphene on dielectric substrates [silicon dioxide (SiO(2)) or quartz] using an oxygen-aided chemical vapor deposition (CVD) process. The growth was carried out using a CVD system at atmospheric pressure. After high-temperature activation of the growth substrates in air, high-quality polycrystalline graphene is subsequently grown on SiO(2) by utilizing the oxygen-based nucleation sites. The growth mechanism is analogous to that of growth for single-walled carbon nanotubes. Graphene-modified SiO(2) substrates can be directly used in transparent conducting films and field-effect devices. The carrier mobilities are about 531 cm(2) V(-1) s(-1) in air and 472 cm(2) V(-1) s(-1) in N(2), which are close to that of metal-catalyzed polycrystalline graphene. The method avoids the need for either a metal catalyst or a complicated and skilled postgrowth transfer process and is compatible with current silicon processing techniques.

Freestanding paper-like electrode materials have trigged significant research interest for their practical application in flexible and lightweight energy storage devices. In this work, we reported a new type of flexible nanohybrid paper electrode based on full inkjet printing synthesis of a freestanding graphene paper (GP) supported three-dimensional (3D) porous graphene hydrogel (GH)–polyaniline (PANI) nanocomposite, and explored its practical application in flexible all-solid-state supercapacitor (SC). The utilization of 3D porous GH scaffold to load nanostructured PANI dramatically enhances the electrical conductivity, the specific capacitance and the cycle stability of the GH–PANI nanocomposite. Additionally, GP can intimately interact with GH–PANI through π–π stacking to form a unique freestanding GP supported GH–PANI nanocomposite (GH–PANI/GP) with distinguishing mechanical, electrochemical and capacitive properties. These exceptional attributes, coupled with the merits of full inkjet printing strategy, lead to the formation of a high-performance binder-free paper electrode for flexible and lightweight SC application. The flexible all-solid-state symmetric SC based on GH–PANI/GP electrode and gel electrolyte exhibits remarkable mechanical flexibility, high cycling performance and acceptable energy density of 24.02 Wh kg–1 at a power density of 400.33 W kg–1. More importantly, the proposed simple and scale-up full inkjet printing procedure for the preparation of freestanding GP supported 3D porous GH-PANI nanocomposite is a modular approach to fabricate other graphene-based nanohybrid papers with tailorable properties and optimal components.

The ability to dope graphene is highly important for modulating electrical properties of graphene. However, the current route for the synthesis of N-doped graphene by chemical vapor deposition (CVD) method mainly involves high growth temperature using ammonia gas or solid reagent melamine as nitrogen sources, leading to graphene with low doping level, polycrystalline nature, high defect density and low carrier mobility. Here, we demonstrate a self-assembly approach that allows the synthesis of single-layer, single crystal and highly nitrogen-doped graphene domain arrays by self-organization of pyridine molecules on Cu surface at temperature as low as 300 °C. These N-doped graphene domains have a dominated geometric structure of tetragonal-shape, reflecting the single crystal nature confirmed by electron-diffraction measurements. The electrical measurements of these graphene domains showed their high carrier mobility, high doping level, and reliable N-doped behavior in both air and vacuum.

Abstract Particular attention has been focused on n‐channel organic thin‐film transistors (OTFTs) during the last few years, and the potentially cost‐effective circuitry‐based applications in flexible electronics, such as flexible radiofrequency identity tags, smart labels, and simple displays, will benefit from this fast development. This article reviews recent progress in performance and molecular design of n‐channel semiconductors in the past five years, and limitations and practicable solutions for n‐channel OTFTs are dealt with from the viewpoint of OTFT constitution and geometry, molecular design, and thin‐film growth conditions. Strategy methodology is especially highlighted with an aim to investigate basic issues in this field.

We report the synthesis, characterization, and application of a novel series of diketopyrrolopyrrole (DPP)-containing quinoidal small molecules as highly efficient n-type organic semiconductors in thin film transistors (TFTs). The first two representatives of these species exhibit maximum electron mobility up to 0.55 cm2 V–1 s–1 with current on/current off (Ion/Ioff) values of 106 for 1 by vapor evaporation, and 0.35 cm2 V–1 s–1 with Ion/Ioff values of 105–106 for 2 by solution process in air, which is the first demonstration of DPP-based small molecules offering only electron transport characteristics in TFT devices. The results indicate that incorporation of a DPP moiety to construct quinoidal architecture is an effective approach to enhance the charge-transport capability.

A new class of n-type semiconductors for organic thin film transistors (OTFTs), based on core-expanded naphthalene diimides fused with 2-(1,3-dithiol-2-ylidene)malonitrile groups, is reported. The first two representatives of these species, derived from long branched N-alkyl chains, have been successfully used as active layers for high-performance, ambient-stable, solution-processed n-channel OTFTs. Their bottom-gate top-contact devices fabricated by spin-coating methods exhibit high electron mobilities of up to 0.51 cm(2) V(-1) s(-1) with current on/off ratios of 10(5)-10(7), and small threshold voltages below 10 V under ambient conditions. As this class of n-type organic semiconductors has relatively low-lying LUMO levels and good film-formation ability, they also displayed good environmental stability even with prolonged exposure to ambient air. Both the device performance and the ambient stability are among the best for n-channel OTFTs reported to date.

The HER catalytic efficiency of cobalt phosphide-based catalysts can be enhanced significantly by adjusting crystalline phase and carbon species structures.

CeO2, which was used as support to prepare mesoporous Ni/CeO2 catalyst, was prepared by the hard-template method. The prepared NiO/CeO2 precursor and Ni/CeO2 catalyst were studied by H2–TPR, in-situ XPS, and in-situ FT-IR. The catalytic properties of the prepared Ni/CeO2 catalyst were also investigated by CO2 catalytic hydrogenation methanation. H2–TPR and in-situ XPS results showed that metal Ni species and surface oxygen vacancies could be formed by H2 reduction. In-situ FT-IR and in-situ XPS results indicated that CO2 molecules could be reduced by active metal Ni species and surface oxygen vacancies to generate active CO species and promote CO2 methanation. The Ni/CeO2 catalyst presented the high CO2 methanation activity, and CO2 conversion and CH4 selectivity reached 91.1% and 100% at 340 °C and atmospheric pressure.

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTExperimental Techniques for the Fabrication and Characterization of Organic Thin Films for Field-Effect TransistorsYugeng Wen, Yunqi Liu*, Yunlong Guo, Gui Yu, and Wenping HuView Author Information Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China*E-mail: [email protected]Cite this: Chem. Rev. 2011, 111, 5, 3358–3406Publication Date (Web):March 14, 2011Publication History Received19 June 2010Published online14 March 2011Published inissue 11 May 2011https://doi.org/10.1021/cr1001904Copyright © 2011 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views12542Altmetric-Citations213LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (35 MB) Get e-AlertsSUBJECTS:Aromatic compounds,Electrodes,Hydrocarbons,Layers,Thin films Get e-Alerts

We report a facile and green method to synthesize a new type of catalyst by coating Pd nanoparticles (NPs) on reduced graphene oxide (rGO)-carbon nanotube (CNT) nanocomposite. An rGO-CNT nanocomposite with three-dimensional microstructures was obtained by hydrothermal treatment of an aqueous dispersion of graphene oxide (GO) and CNTs. After the rGO-CNT composites have been dipped in K₂PdCl₄ solution, the spontaneous redox reaction between the GO-CNT and PdCl₄(2-) led to the formation of nanohybrid materials consisting rGO-CNT decorated with 4 nm Pd NPs, which exhibited excellent and stable catalytic activity: the reduction of 4-nitrophenol to 4-aminophenol using NaBH4 as a catalyst was completed in only 20 s at room temperature, even when the Pd content of the catalyst was 1.12 wt%. This method does not require rigorous conditions or toxic agents and thus is a rapid, efficient, and green approach to the fabrication of highly active catalysts.

Advanced MaterialsVolume 26, Issue 10 p. 1559-1564 Communication Monolayer Hexagonal Boron Nitride Films with Large Domain Size and Clean Interface for Enhancing the Mobility of Graphene-Based Field-Effect Transistors Lifeng Wang, Lifeng Wang Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Science, Beijing, 100190 P. R. China Key Lab of Microsystem and Microstructure, Harbin Institute of Technology, Harbin, 150080 P. R. China [+]These authors contributed equally to this workSearch for more papers by this authorBin Wu, Bin Wu Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Science, Beijing, 100190 P. R. China [+]These authors contributed equally to this workSearch for more papers by this authorJisi Chen, Jisi Chen Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Science, Beijing, 100190 P. R. ChinaSearch for more papers by this authorHongtao Liu, Hongtao Liu Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Science, Beijing, 100190 P. R. ChinaSearch for more papers by this authorPingan Hu, Corresponding Author Pingan Hu Key Lab of Microsystem and Microstructure, Harbin Institute of Technology, Harbin, 150080 P. R. ChinaE-mail: [email protected], [email protected]Search for more papers by this authorYunqi Liu, Corresponding Author Yunqi Liu Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Science, Beijing, 100190 P. R. ChinaE-mail: [email protected], [email protected]Search for more papers by this author Lifeng Wang, Lifeng Wang Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Science, Beijing, 100190 P. R. China Key Lab of Microsystem and Microstructure, Harbin Institute of Technology, Harbin, 150080 P. R. China [+]These authors contributed equally to this workSearch for more papers by this authorBin Wu, Bin Wu Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Science, Beijing, 100190 P. R. China [+]These authors contributed equally to this workSearch for more papers by this authorJisi Chen, Jisi Chen Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Science, Beijing, 100190 P. R. ChinaSearch for more papers by this authorHongtao Liu, Hongtao Liu Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Science, Beijing, 100190 P. R. ChinaSearch for more papers by this authorPingan Hu, Corresponding Author Pingan Hu Key Lab of Microsystem and Microstructure, Harbin Institute of Technology, Harbin, 150080 P. R. ChinaE-mail: [email protected], [email protected]Search for more papers by this authorYunqi Liu, Corresponding Author Yunqi Liu Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Science, Beijing, 100190 P. R. ChinaE-mail: [email protected], [email protected]Search for more papers by this author First published: 17 December 2013 https://doi.org/10.1002/adma.201304937Citations: 207 Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Graphical Abstract Viable and general techniques that allow effective size control of triangular-shaped, single-crystal, monolayer h-BN domains grown by the CVD method, direct optical visualization of h-BN domains, and the cleaning of the h-BN surface to achieve reliable graphene device quality are reported for the first time. This study points to a critical role of the interfacial properties between the graphene and the monolayer h-BN in determining reliable, enhanced graphene-device performance. Supporting Information As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Filename Description adma201304937-sup-0001-S1.pdf931.5 KB Supplementary Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. References 1A. K. Geim, I. V. Grigorieva, Nature 2013, 499, 419–425. 10.1038/nature12385 CASPubMedWeb of Science®Google Scholar 2K. Watanabe, T. Taniguchi, H. Kanda, Nat. Mater. 2004, 3, 404–409. 10.1038/nmat1134 CASPubMedWeb of Science®Google Scholar 3L. Song, L. Ci, H. Lu, P. B. Sorokin, C. H. Jin, J. Ni, A. G. Kvashnin, D. G. Kvashnin, J. Lou, B. I. Yakobson, P. M. Ajayan, Nano Lett. 2010, 10, 3209–3215. 10.1021/nl1022139 CASPubMedWeb of Science®Google Scholar 4Y. Chen, J. Zou, S. J. Campbell, G. Le Caer, Appl. Phys. Lett. 2004, 84, 2430–2432. 10.1063/1.1667278 CASWeb of Science®Google Scholar 5C. R. Dean, A. F. Young, I. Meric, C. Lee, L. Wang, S. Sorgenfrei, K. Watanabe, T. 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Nickel phosphide nanoparticles decorated on carbon nanotubes were synthesized by <italic>in situ</italic> thermal decomposition for the first time. The Ni₂P/CNT nanohybrid exhibits high activity and stability for hydrogen evolution.

Abstract Flexible electronics have suggested tremendous potential to shape human lives for more convenience and pleasure. Strenuous efforts have been devoted to developing flexible organic field-effect transistor (FOFET) technologies for rollable displays, bendable smart cards, flexible sensors and artificial skins. However, these applications are still in a nascent stage for lack of standard high-performance material stacks as well as mature manufacturing technologies. In this review, the material choice and device design for FOFET devices and circuits, as well as the demonstrated applications are summarized in detail. Moreover, the technical challenges and potential applications of FOFETs in the future are discussed.

Advanced MaterialsVolume 24, Issue 19 p. 2603-2607 Communication Sulfur-Bridged Annulene-TCNQ Co-Crystal: A Self-Assembled ''Molecular Level Heterojunction'' with Air Stable Ambipolar Charge Transport Behavior Jing Zhang, Jing Zhang Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Graduate University of Chinese Academy of Sciences, Beijing 100049, P. R. ChinaSearch for more papers by this authorHua Geng, Hua Geng Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorTarunpreet Singh Virk, Tarunpreet Singh Virk Organic Synthesis Laboratory, Department of Applied Chemical Sciences & Technology, Guru Nanak Dev University, Amritsar-143005, IndiaSearch for more papers by this authorYan Zhao, Yan Zhao Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Graduate University of Chinese Academy of Sciences, Beijing 100049, P. R. ChinaSearch for more papers by this authorJiahui Tan, Jiahui Tan Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Graduate University of Chinese Academy of Sciences, Beijing 100049, P. R. ChinaSearch for more papers by this authorChong-an Di, Chong-an Di Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorWei Xu, Corresponding Author Wei Xu [email protected] Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Wei Xu, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Zhigang Shuai, Chemistry Department, Tsinghua University, Beijing, China. Daoben Zhu, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorKamaljit Singh, Kamaljit Singh Organic Synthesis Laboratory, Department of Applied Chemical Sciences & Technology, Guru Nanak Dev University, Amritsar-143005, IndiaSearch for more papers by this authorWenping Hu, Wenping Hu Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorZhigang Shuai, Corresponding Author Zhigang Shuai [email protected] Chemistry Department, Tsinghua University, Beijing, China Wei Xu, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Zhigang Shuai, Chemistry Department, Tsinghua University, Beijing, China. Daoben Zhu, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorYunqi Liu, Yunqi Liu Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorDaoben Zhu, Corresponding Author Daoben Zhu [email protected] Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Wei Xu, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Zhigang Shuai, Chemistry Department, Tsinghua University, Beijing, China. Daoben Zhu, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this author Jing Zhang, Jing Zhang Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Graduate University of Chinese Academy of Sciences, Beijing 100049, P. R. ChinaSearch for more papers by this authorHua Geng, Hua Geng Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorTarunpreet Singh Virk, Tarunpreet Singh Virk Organic Synthesis Laboratory, Department of Applied Chemical Sciences & Technology, Guru Nanak Dev University, Amritsar-143005, IndiaSearch for more papers by this authorYan Zhao, Yan Zhao Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Graduate University of Chinese Academy of Sciences, Beijing 100049, P. R. ChinaSearch for more papers by this authorJiahui Tan, Jiahui Tan Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Graduate University of Chinese Academy of Sciences, Beijing 100049, P. R. ChinaSearch for more papers by this authorChong-an Di, Chong-an Di Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorWei Xu, Corresponding Author Wei Xu [email protected] Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Wei Xu, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Zhigang Shuai, Chemistry Department, Tsinghua University, Beijing, China. Daoben Zhu, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorKamaljit Singh, Kamaljit Singh Organic Synthesis Laboratory, Department of Applied Chemical Sciences & Technology, Guru Nanak Dev University, Amritsar-143005, IndiaSearch for more papers by this authorWenping Hu, Wenping Hu Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorZhigang Shuai, Corresponding Author Zhigang Shuai [email protected] Chemistry Department, Tsinghua University, Beijing, China Wei Xu, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Zhigang Shuai, Chemistry Department, Tsinghua University, Beijing, China. Daoben Zhu, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorYunqi Liu, Yunqi Liu Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorDaoben Zhu, Corresponding Author Daoben Zhu [email protected] Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Wei Xu, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Zhigang Shuai, Chemistry Department, Tsinghua University, Beijing, China. Daoben Zhu, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this author First published: 13 April 2012 https://doi.org/10.1002/adma.201200578Citations: 200Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Graphical Abstract An alternatively stacked donor-acceptor complex from solution is obtained. As a self-assembled "molecular level heterojunction", this crystal displays stable ambipolar transport behaviors in ambient atmosphere. The balance hole and electron transport properties are rationalized through theoretical considerations from band structure calculation, theoretical analysis on super-exchange effects in the intermolecular electronic couplings as well as molecular reorganization energy. Supporting Information Detailed facts of importance to specialist readers are published as "Supporting Information". Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Filename Description adma_201200578_sm_suppl.pdf292.9 KB suppl Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. References 1 a) J. Zaumseil, H. Sirringhaus, Chem. 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Citing Literature Volume24, Issue19May 15, 2012Pages 2603-2607 ReferencesRelatedInformation

Advanced Energy MaterialsVolume 3, Issue 9 p. 1166-1170 Communication A Solution-Processable Small Molecule Based on Benzodithiophene and Diketopyrrolopyrrole for High-Performance Organic Solar Cells Yuze Lin, Yuze Lin Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China University of Chinese Academy of Sciences, Beijing 100049, P. R. ChinaSearch for more papers by this authorLanchao Ma, Lanchao Ma Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China University of Chinese Academy of Sciences, Beijing 100049, P. R. ChinaSearch for more papers by this authorYongfang Li, Yongfang Li Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorYunqi Liu, Yunqi Liu Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorDaoben Zhu, Daoben Zhu Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorXiaowei Zhan, Corresponding Author Xiaowei Zhan [email protected] Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, P. R. ChinaBeijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.Search for more papers by this author Yuze Lin, Yuze Lin Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China University of Chinese Academy of Sciences, Beijing 100049, P. R. ChinaSearch for more papers by this authorLanchao Ma, Lanchao Ma Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China University of Chinese Academy of Sciences, Beijing 100049, P. R. ChinaSearch for more papers by this authorYongfang Li, Yongfang Li Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorYunqi Liu, Yunqi Liu Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorDaoben Zhu, Daoben Zhu Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. ChinaSearch for more papers by this authorXiaowei Zhan, Corresponding Author Xiaowei Zhan [email protected] Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, P. R. ChinaBeijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.Search for more papers by this author First published: 08 May 2013 https://doi.org/10.1002/aenm.201300181Citations: 196Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Graphical Abstract A linear solution-processable small molecule (BDT-2DPP) based on 5-alkylthiophene-2-yl-substituted benzodithiophene and diketopyrrolopyrrole is designed and synthesized. BDT-2DPP exhibits strong and broad absorption with low band gap, low lying energy levels matching with PC61BM and high hole mobility. Solution-processed organic solar cells based on BDT-2DPP:PC61BM blend showed power conversion efficiencies as high as 5.79%. Citing Literature Supporting Information As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Filename Description aenm_201300181_sm_suppl.pdf419.1 KB suppl Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. 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Exploring high-performance zeolite-supported metal catalysts is of great significance. Herein, we develop a strategy for fabricating isolated single metal atomic site catalysts in Y zeolite (M-ISAS@Y, M = Pt, Pd, Ru, Rh, Co, Ni, Cu) by in situ separating and confining a metal-ethanediamine complex into β-cages during the crystallization process followed by thermal treatment. The M-ISAS are stabilized by skeletal oxygens of Y zeolite, and the crystallinity, porosity, and large surface area are well inherited in M-ISAS@Y. As a demonstration, acidic Pt-ISAS@Y is used for n-hexane isomerization involving consecutive catalytic dehydrogenation/hydrogenation on Pt-ISAS and isomerization on Brønsted acid sites. The turnover frequency value of Pt-ISAS reaches 727 h-1, 5 times more than Pt nanoparticles (∼3.5 nm), with a total isomer selectivity of more than 98%. This strategy provides a convenient route to fabricate promising zeolite-based M-ISAS catalysts for industrial applications.

Near-infrared organic photodetectors (NIR OPDs) own some unique properties such as tailorable optoelectronic properties, ease of processing, compatibility with flexible substrates, and operation at room temperature. Therefore, NIR OPDs are attractive candidates for future electronic products due to the increasingly desired for wearable electronic devices and biomedical applications. In order to fulfill this goal, it is extremely necessary to fabricate high-performance NIR OPDs. In this review, we present a broad overview of advances in NIR OPDs from the perspective of material selection and device performance optimization over the past decade, and we also summarize the potential applications of NIR OPDs. At last, we undergo a deep discussion about the challenges and prospects for the future development of organic NIR OPDs.

Rational heteroatom engineering is applied to develop high-performance electron-transporting naphthalenediimide copolymers. Top-gate field-effect transistors fabricated from selenophene-containing polymers achieve an ultrahigh electron mobility of 8.5 cm2 V−1 s−1 and excellent air-stability. The results demonstrate that the incorporation of selenophene heterocycles into the polymers can improve the film-forming ability, intermolecular interaction, and carrier transport significantly. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

A photonic integrated circuit (PIC) is the optical analogy of an electronic loop in which photons are signal carriers with high transport speed and parallel processing capability. Besides the most frequently demonstrated silicon-based circuits, PICs require a variety of materials for light generation, processing, modulation, and detection. With their diversity and flexibility, organic molecular materials provide an alternative platform for photonics; however, the versatile fabrication of organic integrated circuits with the desired photonic performance remains a big challenge. The rapid development of flexible electronics has shown that a solution printing technique has considerable potential for the large-scale fabrication and integration of microsized/nanosized devices. We propose the idea of soft photonics and demonstrate the function-directed fabrication of high-quality organic photonic devices and circuits. We prepared size-tunable and reproducible polymer microring resonators on a wafer-scale transparent and flexible chip using a solution printing technique. The printed optical resonator showed a quality (Q) factor higher than 4 × 10(5), which is comparable to that of silicon-based resonators. The high material compatibility of this printed photonic chip enabled us to realize low-threshold microlasers by doping organic functional molecules into a typical photonic device. On an identical chip, this construction strategy allowed us to design a complex assembly of one-dimensional waveguide and resonator components for light signal filtering and optical storage toward the large-scale on-chip integration of microscopic photonic units. Thus, we have developed a scheme for soft photonic integration that may motivate further studies on organic photonic materials and devices.

Abstract 2D layered materials have emerged in recent years as a new platform to host novel electronic, optical, or excitonic physics and develop unprecedented nanoelectronic and energy applications. By definition, these materials are strongly anisotropic between the basal plane and cross the plane. The structural and property anisotropies inside their basal plane, however, are much less investigated. Black phosphorus, for example, is a 2D material that has such in‐plane anisotropy. Here, a rare chemical form of arsenic, called black‐arsenic (b‐As), is reported as a cousin of black phosphorus, as an extremely anisotropic layered semiconductor. Systematic characterization of the structural, electronic, thermal, and electrical properties of b‐As single crystals is performed, with particular focus on its anisotropies along two in‐plane principle axes, armchair (AC) and zigzag (ZZ). The analysis shows that b‐As exhibits higher or comparable electronic, thermal, and electric transport anisotropies between the AC and ZZ directions than any other known 2D crystals. Such extreme in‐plane anisotropies can potentially implement novel ideas for scientific research and device applications.

The enhancement of catalytic performance of cobalt phosphide-based catalysts for the hydrogen evolution reaction (HER) is still challenging. In this work, the doping effect of some transition metal (M = Fe, Ni, Cu) on the electrocatalytic performance of the M-Co2P/NCNTs (NCNTs, nitrogen-doped carbon nanotubes) hybrid catalysts for the HER was studied systematically. The M-Co2P/NCNTs hybrid catalysts were synthesized via a simple in situ thermal decomposition process. A series of techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma-optical emission spectrometry, transmission electron microscopy, and N2 sorption were used to characterize the as-synthesized M-Co2P/NCNTs hybrid catalysts. Electrochemical measurements showed the catalytic performance according to the following order of Fe-Co2P/NCNTs > Ni-Co2P/NCNTs > Cu-Co2P/NCNTs, which can be ascribed to the difference of structure, morphology, and electronic property after doping. The doping of Fe atoms promote the growth of the [111] crystal plane, resulting in a large specific area and exposing more catalytic active sites. Meanwhile, the Fe(δ+) has the highest positive charge among all the M-Co2P/NCNTs hybrid catalysts after doping. All these changes can be used to contribute the highest electrocatalytic activity of the Fe-Co2P/NCNTs hybrid catalyst for HER. Furthermore, an optimal HER electrocatalytic activity was obtained by adjusting the doping ratio of Fe atoms. Our current research indicates that the doping of metal is also an important strategy to improve the electrocatalytic activity for the HER.

We demonstrate the fabrication of long-period fiber gratings (LPFGs) written in the two-mode fiber (TMF) by CO2 laser. Both uniform and tilted LPFGs were fabricated to provide the light coupling between LP01 mode and LP11 mode with a coupling efficiency of more than 99%. The writing efficiency and the bandwidth of the LPFG mode converter can be adjusted by changing the tilt angle of the tilted TMF-LPFGs. The torsion sensitivity of conventional and tilted LPFG mode converters were measured to be 0.37 nm/(rad/m) and 0.50 nm/(rad/m), respectively. Two orthogonal vector modes (the HEeven 21and HEodd 21 modes) and corresponding orbital angular momentum state were successfully obtained at the resonance wavelength. The proposed LPFG mode converter could be used as not only a high efficiency wavelength tunable mode converter in the mode division multiplexing system but also a high sensitive torsion sensor in the field of optical sensing.

Abstract We reported a scalable and modular method to prepare a new type of sandwich-structured graphene-based nanohybrid paper and explore its practical application as high-performance electrode in flexible supercapacitor. The freestanding and flexible graphene paper was firstly fabricated by highly reproducible printing technique and bubbling delamination method, by which the area and thickness of the graphene paper can be freely adjusted in a wide range. The as-prepared graphene paper possesses a collection of unique properties of highly electrical conductivity (340 S cm −1 ), light weight (1 mg cm −2 ) and excellent mechanical properties. In order to improve its supercapacitive properties, we have prepared a unique sandwich-structured graphene/polyaniline/graphene paper by in situ electropolymerization of porous polyaniline nanomaterials on graphene paper, followed by wrapping an ultrathin graphene layer on its surface. This unique design strategy not only circumvents the low energy storage capacity resulting from the double-layer capacitor of graphene paper, but also enhances the rate performance and cycling stability of porous polyaniline. The as-obtained all-solid-state symmetric supercapacitor exhibits high energy density, high power density, excellent cycling stability and exceptional mechanical flexibility, demonstrative of its extensive potential applications for flexible energy-related devices and wearable electronics.

The detection of samples at ultralow concentrations (one to ten copies in 100 μl) in biofluids is hampered by the orders-of-magnitude higher amounts of ‘background’ biomolecules. Here we report a molecular system, immobilized on a liquid-gated graphene field-effect transistor and consisting of an aptamer probe bound to a flexible single-stranded DNA cantilever linked to a self-assembled stiff tetrahedral double-stranded DNA structure, for the rapid and ultrasensitive electromechanical detection (down to one to two copies in 100 μl) of unamplified nucleic acids in biofluids, and also of ions, small molecules and proteins, as we show for Hg2+, adenosine 5′-triphosphate and thrombin. We implemented an electromechanical biosensor for the detection of SARS-CoV-2 into an integrated and portable prototype device, and show that it detected SARS-CoV-2 RNA in less than four minutes in all nasopharyngeal samples from 33 patients with COVID-19 (with cycle threshold values of 24.9–41.3) and in none of the 54 COVID-19-negative controls, without the need for RNA extraction or nucleic acid amplification. A self-assembled DNA-based system immobilized on a liquid-gated graphene field-effect transistor can electromechanically detect ultralow levels of unamplified ions, nucleic acids, small molecules and proteins in biofluids.

Development of hybrid catalysts with high activity, good stability and low cost is extremely desirable for hydrogen production by electrolysis of water. In this work, a hybrid composed of Ni2P nanoparticles (NPs) on N-doped reduced graphene oxide (NRGO) is synthesized via an in situ thermal decomposition approach for the first time and investigated as a catalyst for the hydrogen evolution reaction (HER). The as-synthesized Ni2P/NRGO hybrid exhibits an enhanced catalytic activity with low onset overpotential (37 mV), a small Tafel slope (59 mV dec−1), a much larger exchange current density (4.9 × 10−5 A cm−2), and lower HER activation energy (46.9 kJ mol−1) than Ni2P/RGO hybrid. In addition, the Ni2P/NRGO hybrid maintains its catalytic activity for at least 60′000 s in acidic media. The enhanced catalytic activity is attributed to the synergistic effect of N-doped RGO and Ni2P NPs, the charged natures of Ni and P, as well as the high electrical conductivity of Ni2P/NRGO hybrid. This study may offer a new strategy for improving the electrocatalytic activity for hydrogen production.

A novel 2D benzodifuran (BDF)-based copolymer (PBDF-T1) is synthesized. Polymer solar cells fabricated with PBDF-T1 show high power conversion efficiency of 9.43% and fill factor of 77.4%, which is higher than the performance of its benzothiophene (BDT) counterpart (PBDT-T1). These results provide important progress for BDF-based copolymers and demonstrate that BDF-based copolymers can be competitive with the well-studied BDT counterparts via molecular structure design and device optimization.

Cobalt nickel phosphide nanoparticle decorated carbon nanotubes (Co_2−xNi_xP/CNTs) as efficient hybrid catalysts for enhanced hydrogen evolution reaction catalytic activity.

Abstract The emergence of flexible organic electronics that span the fields of physics and biomimetics creates the possibility for increasingly simple and intelligent products for use in everyday life. Organic field‐effect transistors (OFETs), with their inherent flexibility, light weight, and biocompatibility, have shown great promise in the field of biomimicry. By applying such biomimetic OFETs for the internet of things (IoT) makes it possible to imagine novel products and use cases for the future. Recent advances in flexible OFETs and their applications in biomimetic systems are reviewed. Strategies to achieve flexible OFETs are individually discussed and recent progress in biomimetic sensory systems and nervous systems is reviewed in detail. OFETs are revealed to be one of the best systems for mimicking sensory and nervous systems. Additionally, a brief discussion of information storage based on OFETs is presented. Finally, a personal view of the utilization of biomimetic OFETs in the IoT and future challenges in this research area are provided.

Abstract Owing to their excellent physical and electrical properties, metal–organic framework (MOF) materials with well‐defined supramolecular structures have received extensive research attention. However, the fabrication of large‐area two‐dimensional (2D) MOF films is still a significant challenge. Herein, we propose a novel electrochemical (EC) synthesis method for the preparation of large‐area Cu 3 (HHTP) 2 MOF film on single‐crystal Cu (100) anode. The surface reaction was achieved via charge‐induced molecular assembly. The synthesized MOF film exhibited a high crystalline quality with an electrical conductivity of approximately 0.087 S cm −1 , which was around 1000 times larger than the previously reported values for the same material prepared by the interface method. In addition, Cu 2 (MTCP), Cu 3 (BTPA) 2 , and Cu 3 (TPTC) 2 MOF films were synthesized on Cu foil with the same strategy, which confirmed the universality of the proposed method. This controllable EC method can be effectively applied to the industrial‐scale production of 2D MOF films on Cu foil.

A coupling catalyst of highly dispersed N, P co-doped carbon frames (NPCFs) anchored with Fe single atoms (SAs) and Fe2 P nanoparticles (NPs) is synthesized by a novel in situ doping-adsorption-phosphatization strategy for the electrocatalytic oxygen reduction reaction (ORR). The optimized Fe SAs-Fe2 P NPs/NPCFs-2.5 catalyst shows a superior ORR activity and stability in 0.5 m H2 SO4 and 0.1 m KOH, respectively. Theoretical calculations reveal a synergistic effect, in that the existence of Fe2 P weakens the adsorption of ORR intermediates on active sites and lowers the reaction free energy. The doped P atoms with a strong electron-donating ability elevate the energy level of Fe-3d orbitals and facilitate the adsorption of O2 . The active Fe atoms exist in a low oxidation state and are less positively charged, and they serve as an electron reservoir capable of donating and releasing electrons, thus improving the ORR activity. Operando and in situ characterization results indicate that the atomically dispersed FeN4 /FeP coupled active centers in the Fe SAs-Fe2 P NPs/NPCFs-2.5 catalyst are characteristic of the different catalytic mechanisms in acidic and alkaline media. This work proposes a novel idea for constructing coupling catalysts with atomic-level precision and provides a strong reference for the development of high-efficiency ORR electrocatalysts for practical application.

Abstract The modulation effect manifests an encouraging potential to enhance the performance of single‐atom catalysts; however, the in‐depth study about this effect for the isolated diatomic sites (DASs) remains a great challenge. Herein, a proximity electronic effect (PEE) of Ni/Co DASs is proposed that is anchored in N‐doped carbon (N‐C) substrate (NiCo DASs/N‐C) for synergistic promoting electrocatalytic oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). Benefiting from the PEE of adjacent Ni anchored by four nitrogen (Ni‐N 4 ) moiety, NiCo DASs/N‐C catalyst exhibits superior ORR and HER activity. In situ characterization results suggest Co anchored by four nitrogen (Co‐N 4 ) as main active site for O 2 adsorption‐activation process, which promotes the formation of key *OOH and the desorption of *OH intermediate to accelerate the multielectron reaction kinetics. Theoretical calculation reveals the adjacent Ni‐N 4 site as a modulator can effectively adjust the electronic localization of proximity Co‐N 4 site, promoting the *OH desorption and *H adsorption on Co‐N 4 site, thereby boosting ORR and HER process significantly. This study opens a new opportunity for rationally regulating the electronic localization of catalytic active centers by proximity single‐atom moiety, as well as provides guidance for designing high‐efficiency bifunctional electrocatalysts for promising applications.

As for the common synthesis methods of ameliorated Zn2SnO4 (ZSO), additional oxides refer to Zn or Sn or Zn/Sn would be introduced into the doped system synchronously, thereby the achievement of doped pure ZSO appears particularly difficult. In this study, a novel bismuth (Bi) nanoparticles modified ZSO composite with oxygen vacancies (OVs-BZSO) was fabricated via a facile one-pot hydrothermal approach. According to XRD and XPS analysis results, it was found that the metallic Bi nanoparticles were successfully introduced into ZSO. In addition, based on the results of XPS and EPR measurements, the existence of OVs in the ZSO was also affirmed. On this basis, the DFT calculation was employed to reveal the position of OVs, the electronic structure and charge transport properties of the interface between Bi and ZSO. Furthermore, it was observed that the introduction of OVs not only diminishes the bandgap induced by an intermediate gap but also services as active centers to favor the adsorptions of small molecules such as NO, O2 and H2O as revealed by DFT simulations to promote the formation of reactive species. While the addition of metallic Bi nanoparticles into ZSO for one thing enhances the light harvesting capacity endowed by SPR effect as evidenced by UV–vis DRS result, for another accelerates the separation of photo-generated carriers by virtue of Schottky barrier formed at the metallic Bi and ZSO interface. Therefore, the synergistic effect of OVs and Bi nanoparticles can thermodynamically drive the adsorption/activation of NO molecules, benefitting the directional migration and effective separation of electrons in OVs-BZSO, all of which serviced the efficient NO removal rate with the illumination of visible light. Meanwhile, for OVs-BZSO, in-situ infrared spectroscopy results indicated that the formation of toxic by-products was greatly bridled, thus a fresh charge transfer path: Bi nanoparticles → ZSO → gas molecules and a unique NO reaction path were proposed accordingly. This study can provide new insights on controllable preparation and reaction mechanism of ZSO-based photocatalysts.

Rapid screening of infected individuals from a large population is an effective means in epidemiology, especially to contain outbreaks such as COVID-19. The gold standard assays for COVID-19 diagnostics are mainly based on the reverse transcription polymerase chain reaction, which mismatches the requirements for wide-population screening due to time-consuming nucleic acid extraction and amplification procedures. Here, we report a direct nucleic acid assay by using a graphene field-effect transistor (g-FET) with Y-shaped DNA dual probes (Y-dual probes). The assay relies on Y-dual probes modified on g-FET simultaneously targeting ORF1ab and N genes of SARS-CoV-2 nucleic acid, enabling high a recognition ratio and a limit of detection (0.03 copy μL–1) 1–2 orders of magnitude lower than existing nucleic acid assays. The assay realizes the fastest nucleic acid testing (∼1 min) and achieves direct 5-in-1 pooled testing for the first time. Owing to its rapid, ultrasensitive, easily operated features as well as capability in pooled testing, it holds great promise as a comprehensive tool for population-wide screening of COVID-19 and other epidemics.

Abstract The progress of neural synaptic devices is experiencing an era of explosive growth. Given that the traditional storage system has yet to overcome the von Neumann bottleneck, it is critical to develop hardware with bioinspired information processing functions and lower power consumption. Transistors based on 2D materials, metal oxides, and organic materials have been adopted to mimic the synapse of a human brain, due to their high plasticity, parallel computing, integrated storage, and system information processing. Among these materials used to build transistors, organic semiconductors are considered to be the most promising candidate for neural synaptic devices and bio‐electronics, owing to their easy processing, mechanical flexibility, low cost, good bio‐compatibility, and ductility. This review focuses on the recent advances in organic synaptic devices with various structures, materials, and working mechanisms. The applications of artificial neural networks that integrate multiple organic synaptic transistors are also concretely discussed. Finally, the challenges that organic synaptic devices currently face are discussed and future developments are forecast.

The low defect content and poor oxygen mobility of perovskite catalysts limit its application in VOC elimination. Herein, we report a strategy involving defect engineering route following an easy urea treatment method to enhance the propane oxidation performance of perovskite catalysts. The constructed LaCoO3-D43 exhibits superior catalytic activity (T90 = 309.3 °C), the T90 value is 150 °C lower than that of LaCoO3, and excellent thermal stability against CO2 and H2O. Experimental results revealed that the urea pyrolysis resulted in the generation of La and O defects and rich surface-active Co species in high-valence states, increasing the utilization of Co active sites. DFT calculations show that the exposed Co surface is conducive to the adsorption and dissociation of oxygen and propane. This work provides a defect engineering strategy to effectively activate perovskite catalysts performance, and can be generalized for the fabrication of other types of perovskite catalysts.

Hydrogen evolution reaction (HER) in neutral media is of great practical importance for sustainable hydrogen production, but generally suffers from low activities, the cause of which has been a puzzle yet to be solved. Herein, by investigating the synergy between Ru single atoms (RuNC) and RuSex cluster compounds (RuSex) for HER using ab initio molecular dynamics, operando X-ray absorption spectroscopy, and operando surface-enhanced infrared absorption spectroscopy, we establish that the interfacial water governs neutral HER. The rigid interfacial water layer in neutral media would inhibit the transport of H2O*/OH* at the electrode/electrolyte interface of RuNC, but the RuSex can promote H2O*/OH* transport to increase the number of available H2O* on RuNC by disordering the interfacial water network. With the synergy of RuSex and RuNC, the resulting neutral HER performance in terms of mass-specific activity is 6.7 times higher than that of 20 wt.% Pt/C at overpotential of 100 mV.

Control over charge carrier density provides an efficient way to trigger phase transitions and modulate the optoelectronic properties of materials. This approach can also be used to induce topological transitions in the optical response of photonic systems. Here we report a topological transition in the isofrequency dispersion contours of hybrid polaritons supported by a two-dimensional heterostructure consisting of graphene and α-phase molybdenum trioxide. By chemically changing the doping level of graphene, we observed that the topology of polariton isofrequency surfaces transforms from open to closed shapes as a result of doping-dependent polariton hybridization. Moreover, when the substrate was changed, the dispersion contour became dominated by flat profiles at the topological transition, thus supporting tunable diffractionless polariton propagation and providing local control over the optical contour topology. We achieved subwavelength focusing of polaritons down to 4.8% of the free-space light wavelength by using a 1.5-μm-wide silica substrate as an in-plane lens. Our findings could lead to on-chip applications in nanoimaging, optical sensing and manipulation of energy transfer at the nanoscale.

Using high-efficiency and low-cost catalyst to replace noble metal platinum for electrocatalytic hydrogen evolution reaction (HER) provides a broad prospect for the development of renewable energy technology, which is an important task yet to be solved. Herein, we proposed an efficient doping–adsorption–pyrolysis strategy for constructing a robust coupling catalyst composed of single-atom Co–N3 sites anchored on an N-doped carbon (N–C) layer and encapsulated Co nanocrystals (NCs) to activate the interfacial water for accelerating HER. Beneficial to the strong synergistic effect of Co–N3 sites and Co NCs, the optimized CoNC-SA/N*–C catalyst showed excellent HER activity and stability in both acidic and alkaline electrolytes. In situ attenuated total reflectance–surface-enhanced infrared absorption spectroscopy revealed that the rigid interfacial water layer of Co–N3 sites inhibited the transport of H2O*/OH*, while Co NCs promoted the transport of H2O*/OH* and increased the amount of available H2O* on Co–N3 sites by disordering the rigid interfacial water network. Theoretical calculation showed that the coupling interface structure destroyed the rigid interfacial network, and Co NCs modified the electronic structure of Co–N3 sites, which is beneficial to H2O dissociation and H adsorption, thus accelerating the HER process. This work opens up new avenues for the construction of coupling catalysts from the atomic scale to activate the interfacial water for boosting HER electrocatalysis.

Ever-growing demands for rechargeable zinc-air batteries (ZABs) call for efficient bifunctional electrocatalysts. Among various electrocatalysts, single atom catalysts (SACs) have received increasing attention due to the merits of high atom utilization, structural tunability, and remarkable activity. Rational design of bifunctional SACs relies heavily on an in-depth understanding of reaction mechanisms, especially dynamic evolution under electrochemical conditions. This requires a systematic study in dynamic mechanisms to replace current trial and error modes. Herein, fundamental understanding of dynamic oxygen reduction reaction and oxygen evolution reaction mechanisms for SACs is first presented combining in situ and/or operando characterizations and theoretical calculations. By highlighting structure-performance relationships, rational regulation strategies are particularly proposed to facilitate the design of efficient bifunctional SACs. Furthermore, future perspectives and challenges are discussed. This review provides a thorough understanding of dynamic mechanisms and regulation strategies for bifunctional SACs, which are expected to pave the avenue for exploring optimum single atom bifunctional oxygen catalysts and effective ZABs.

Designing efficient and durable bifunctional catalysts for 5-hydroxymethylfurfural (HMF) oxidation reaction (HMFOR) and hydrogen evolution reaction (HER) is desirable for the co-production of biomass-upgraded chemicals and sustainable hydrogen, which is limited by the competitive adsorption of hydroxyl species (OHads) and HMF molecules. Here, we report a class of Rh-O5/Ni(Fe) atomic site on nanoporous mesh-type layered double hydroxides with atomic-scale cooperative adsorption centers for highly active and stable alkaline HMFOR and HER catalysis. A low cell voltage of 1.48 V is required to achieve 100 mA cm-2 in an integrated electrolysis system along with excellent stability (>100 h). Operando infrared and X-ray absorption spectroscopic probes unveil that HMF molecules are selectively adsorbed and activated over the single-atom Rh sites and oxidized by in situ-formed electrophilic OHads species on neighboring Ni sites. Theoretical studies further demonstrate that the strong d-d orbital coupling interactions between atomic-level Rh and surrounding Ni atoms in the special Rh-O5/Ni(Fe) structure can greatly facilitate surface electronic exchange-and-transfer capabilities with the adsorbates (OHads and HMF molecules) and intermediates for efficient HMFOR and HER. We also reveal that the Fe sites in Rh-O5/Ni(Fe) structure can promote the electrocatalytic stability of the catalyst. Our findings provide new insights into catalyst design for complex reactions involving competitive adsorptions of multiple intermediates.

Mn-based oxides exhibit attractive catalytic activity for VOCs oxidation, but the catalytic mechanism and kinetics are still significant challenges and rarely mentioned. Therefore, we prepared OMS-2 manganese oxide octahedral molecular sieve with α-MnO2 crystal phase as model compound. By analyzing the properties of the surface chemical states of the catalysts in different reaction stages, combined with the control experiments, the coordination of Mn4+-Osur-Mn3+ was confirmed as the active site at low temperature. Meanwhile, the reaction path of propane catalytic oxidation on MnO2 surface based on condensation mechanism was proved by in-situ spectroscopy and density functional theory calculation. And kinetic studies revealed that the catalytic combustion of propane processed through Langmuir-Hinshelwood mechanism at low temperature. All these systematic study results supplied a well-defined understanding for the propane combustion over manganese oxide.

Wearable electronics are attracting increasing interest due to the emerging Internet of Things (IoT). Compared to their inorganic counterparts, stretchable organic semiconductors (SOSs) are promising candidates for wearable electronics due to their excellent properties, including light weight, stretchability, dissolubility, compatibility with flexible substrates, easy tuning of electrical properties, low cost, and low temperature solution processability for large-area printing. Considerable efforts have been dedicated to the fabrication of SOS-based wearable electronics and their potential applications in various areas, including chemical sensors, organic light emitting diodes (OLEDs), organic photodiodes (OPDs), and organic photovoltaics (OPVs), have been demonstrated. In this review, some recent advances of SOS-based wearable electronics based on the classification by device functionality and potential applications are presented. In addition, a conclusion and potential challenges for further development of SOS-based wearable electronics are also discussed.

Stretchable electronics have received intense attention due to their broad application prospects in many areas, and can withstand large deformations and form close contact with curved surfaces. Stretchable conductors are vital components of stretchable electronic devices used in wearables, soft robots, and human-machine interactions. Recent advances in stretchable conductors have motivated basic scientific and technological research efforts. Here, we outline and analyse the development of stretchable conductors in transistors and circuits, and examine advances in materials, device engineering, and preparation technologies. We divide the existing approaches to constructing stretchable transistors with stretchable conductors into the following two types: geometric engineering and intrinsic stretchability engineering. Finally, we consider the challenges and outlook in this field for delivering stretchable electronics.

Bis(2-(2-hydroxyphenyl)benzothiazolate)zinc (Zn(BTZ)(2)) is one of the best white electroluminescent materials used in organic light-emitting diodes (LEDs). Despite a large number of studies devoted to this complex, very little is known about its basic molecular and electronic structures and electron transport properties in LEDs. Therefore, we investigate the structures and electroluminescent properties. The unsolvated single crystal of Zn(BTZ)(2) was grown and its crystalline structure was determined from X-ray diffraction data. The crystal is triclinic, space group P-1, a = 9.4890(19) A, b = 9.5687(19) A, c = 11.685(2) A, alpha = 84.38(3) degrees, beta = 78.94(3) degrees, gamma = 83.32(3) degrees. The structure of the chelate is dimeric [Zn(BTZ)(2)](2) with two isotropic Zn(2+) ion centers having five-coordinate geometry. The present study provides direct evidence for the sole existence of dimeric structure in the powder and the thin film. The dimer is energetically more stable than the monomer. Analysis of the electronic structure of [Zn(BTZ)(2)](2) calculated by density functional theory reveals a localization of orbital and the distribution of four orbital "tetrads". The structural stabilities of both anion and cation and the distribution of the hole in the cation and that of the excess electron in the anion are discussed in terms of theoretical calculations. Strong intermolecular interaction may be expected to enable good electron transport properties as compared with tris(8-hydroxyquinolinato)aluminum.

Honeycomb-like aligned carbon nanotube films were grown by pyrolysis of iron phthalocyanine. The patterned structure was characterized by a scanning electron micrograph (SEM) and an atomic force micrograph (AFM). Wettability studies revealed the film surface showed a super-hydrophobic property with much higher contact angle (163.4 ± 1.4°) and lower sliding angle (less than 5°)a water droplet moved easily on the surface. In contrast to a densely packed aligned carbon nanotube, the sliding feature was strongly affected by microstructure of surface.

A novel series of conjugated copolymers having oxadiazole, quinoline, quinoxaline, and phenylenecyanovinylene moieties in the main chain based on fluorene were synthesized in good yields by palladium-catalyzed Suzuki coupling reaction, a new approach different from the traditional polyhydrazide precursor route (oxadiazole-containing polymers), acid-catalyzed Friedländer condensation reaction (polyquinolines), and Knoevenagel condensation polymerization (poly(phenylenecyanovinylene)). The thermal, electrochemical, and optical properties of these copolymers were examined. All these polymers possess excellent thermal stability with glass transition temperatures of 114−208 °C and onset decomposition temperatures of 387−415 °C. Cyclic voltammetry studies reveal that these copolymers possess low-lying LUMO energy levels ranging from −3.01 to −3.37 eV and low-lying HOMO energy levels ranging from −6.13 to −6.38 eV and may be promising candidates for electron-transporting or hole-blocking materials in light-emitting diodes. The polymers in thin films emit strong blue luminance around 414−476 nm with narrow bandwidth upon photoexcitation. Photoluminescence spectra of the polymers in the films are only red-shifted by 7−11 nm compared to those in the solution, indicating that the aggregation and the excimer fluorescence are suppressed.

A cyclic ethylene linked triphenylamine dimer formed highly crystalline thin film via vapor deposition. Meanwhile, the corresponding linear molecule only resulted in amorphous films under the same condition. The performance as FET semiconductor also improved significantly when the molecular structure derived from linear to cyclic type. The cyclic molecule displayed mobilities in excess of 10-2 cm2 V-1 s-1 and high on/off ratios up to 107.

Controllable and scalable production is of great importance for the application of graphene; however, to date, it is still a great challenge and a major obstacle which hampers its practical applications. Here, we develop a template chemical vapor deposition method for scalable synthesis of few-layer graphene ribbons (FLGRs) with controlled morphologies. The FLGRs have a good conductivity and are ideal for use in nanoelectromechanics (NEM). As an application, we fabricate a reversible NEM switch and a logic gate by using the FLGRs. This work realizes both controllable and scalable synthesis of graphene, provides an application of graphene in NEM switches, and would be valuable for both the scientific studies and the practical applications of graphene.

Abstract The use of micrometer and nanometer‐sized organic single crystals to fabricate devices can retain all the advantages of single crystals, avoid the difficulties of growing large crystals, and provide a way to characterize organic semiconductors more efficiently. Moreover, the effective use of such “small” crystals will be beneficial to nanoelectronics. Here we review the recent progress of organic single‐crystalline transistors based on micro‐/nanometer‐sized structures, namely fabrication methods and related technical issues, device properties, and current challenges.

LB films of three amphiphilic tris(phthalocyaninato) rare earth triple-decker complexes with crown-ethers as hydrophilic heads and long alkyl chains as hydrophobic tails have been prepared and found to display very well ordered layer structures, as proved by π−A isotherms, UV−vis and polarized absorption spectra, X-ray diffraction experiments, and microscopic morphology characterization. These LB films have been fabricated into field-effect transistor (FET) devices, which show carrier mobilities as high as 0.24−0.60 cm2 V-1 s-1, among the highest mobilities achieved thus far for all LB film-based OFETs.

Advanced MaterialsVolume 21, Issue 19 p. 1954-1959 Communication Multibit Storage of Organic Thin-Film Field-Effect Transistors Yunlong Guo, Yunlong Guo Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China) Graduate School of Chinese Academy of Sciences Beijing 100049 (P. R. China)Search for more papers by this authorChong-an Di, Chong-an Di Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China)Search for more papers by this authorShanghui Ye, Shanghui Ye Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China) Graduate School of Chinese Academy of Sciences Beijing 100049 (P. R. China)Search for more papers by this authorXiangnan Sun, Xiangnan Sun Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China) Graduate School of Chinese Academy of Sciences Beijing 100049 (P. R. China)Search for more papers by this authorJian Zheng, Jian Zheng Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China) Graduate School of Chinese Academy of Sciences Beijing 100049 (P. R. China)Search for more papers by this authorYugeng Wen, Yugeng Wen Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China) Graduate School of Chinese Academy of Sciences Beijing 100049 (P. R. China)Search for more papers by this authorWeiping Wu, Weiping Wu Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China) Graduate School of Chinese Academy of Sciences Beijing 100049 (P. R. China)Search for more papers by this authorGui Yu, Corresponding Author Gui Yu [email protected] Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China)Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China).Search for more papers by this authorYunqi Liu, Corresponding Author Yunqi Liu [email protected] Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China)Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China).Search for more papers by this author Yunlong Guo, Yunlong Guo Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China) Graduate School of Chinese Academy of Sciences Beijing 100049 (P. R. China)Search for more papers by this authorChong-an Di, Chong-an Di Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China)Search for more papers by this authorShanghui Ye, Shanghui Ye Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China) Graduate School of Chinese Academy of Sciences Beijing 100049 (P. R. China)Search for more papers by this authorXiangnan Sun, Xiangnan Sun Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China) Graduate School of Chinese Academy of Sciences Beijing 100049 (P. R. China)Search for more papers by this authorJian Zheng, Jian Zheng Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China) Graduate School of Chinese Academy of Sciences Beijing 100049 (P. R. China)Search for more papers by this authorYugeng Wen, Yugeng Wen Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China) Graduate School of Chinese Academy of Sciences Beijing 100049 (P. R. China)Search for more papers by this authorWeiping Wu, Weiping Wu Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China) Graduate School of Chinese Academy of Sciences Beijing 100049 (P. R. China)Search for more papers by this authorGui Yu, Corresponding Author Gui Yu [email protected] Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China)Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China).Search for more papers by this authorYunqi Liu, Corresponding Author Yunqi Liu [email protected] Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China)Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 (P. R. China).Search for more papers by this author First published: 12 May 2009 https://doi.org/10.1002/adma.200802430Citations: 168AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract Organic thin-film field-effect transistor (OTFT) multibit storage devices are fabricated based on pentacene or copper phthalocyaine (CuPc) with normal polymer modifying layers of polystyrene (PS) or polymethylmethacrylate (PMMA). The devices shows excellent multibit storage properties in a single OTFT using electric and light-assisted programs. Citing Literature Supporting Information Detailed facts of importance to specialist readers are published as "Supporting Information". Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Filename Description adma_200802430_sm_suppdata.pdf1.4 MB suppdata Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. Volume21, Issue19May 18, 2009Pages 1954-1959 RelatedInformation

Analytical formulas are presented for the first time to describe the shift in the resonance wavelength of a long-period fibre grating (LPFG) in response to etching of the fibre cladding or a change in the external refractive index. The accuracy of the formulas is confirmed by comparison with numerical simulations and experimental results. It is shown that the resonance wavelengths of an etched LPFG are more sensitive to the external refractive index than those of an unetched grating.

Large-scale, uniform, vertically standing graphene with atomically thin edges are controllably synthesized on copper foil using a microwave-plasma chemical vapor deposition system. A growth mechanism for this system is proposed. This film shows excellent field-emission properties, with low turn-on field of 1.3 V μm−1, low threshold field of 3.0 V μm−1 and a large field-enhancement factor more than 10 000.

Bulky 4-tritylphenylethynyl substituted boradiazaindacene with pure red emission, relatively large Stokes shift, high fluorescence quantum yield, and low self-quenching was efficiently synthesized and qualified as a potential EL dopant.

Hexagonal graphene flakes: Equiangular hexagon-shaped graphene domains are synthesized by methane chemical vapor deposition on copper surface in a controlled manner. These graphene domains possess either armchair or zigzag edge, and are formed via nucleation and growth mechanism. Left image is a typical AFM image of one graphene flake, and right image indicates the armchair or zigzag edge of hexagonal graphene. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Exploration of high-performance solution-processed n-channel organic transistors with excellent stability is a critical issue for the development of powerful printed circuits. Solution-processed, bottom-gate transistors exhibiting a record electron mobility of up to 1.2 cm2 V−1 s−1 are reported. The devices show excellent stability, which enables the construction of all-solution-processed flexible circuits with all fabrication procedures performed in air. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

A large area and controllable synthesis of well-aligned CNx nanotubes with a high content of nitrogen (x⩽9%) was carried out by pyrolyzing metal phthalocyanine on an n-type Si(100) substrate. The diameters of the CNx nanotubes range widely from 20 to 200 nm, and the lengths range from 1 to 100 μm. The impressive bamboo-like CNx nanotubes consist of a few uniform, small, and well-ordered compartments. Investigation on morphology and elemental composition of the CNx nanotubes suggests that the overall tube morphology depends strongly on the nitrogen concentration. The higher the N content, the more compartmentalized of nanotubes become, which results in the formation of more curved CNx nanotubes. Our studies show that three different types of N atoms can be present in these materials. These are "pyridinic", "pyrrolic", and "graphitic" nitrogen with binding energies of 398.1, 401.0, and 405.1 eV, respectively. Field emission measurements suggest that the CNx nanotubes began to emit electrons at an electric field of 1.5 V/μm, and current densities of 80 μA/cm2 have been realized at an applied field as low as 2.6 V/μm. Doping carbon nanotubes with N enhances their electron-conducting properties because of the presence of additional lone pairs of electrons that act as donors with respect to the delocalized π system of the hexagonal framework. The controllable synthesis of well-aligned CNx nanotubes with high N ratio may open a route to improve the field emission properties of nanotubes.

A solution-processed diketopyrrolopyrrole (DPP)-based small molecule, namely BDT-DPP, with broad absorption and suitable energy levels has been synthesized. The widely used solvents of chloroform (CF) and o-dichlorobenzene (o-DCB) were used as the spin-coating solvent, respectively, and 1,8-diiodooctane (DIO) was used as additive to fabricate efficient photovoltaic devices with BDT-DPP as the donor material and PC71BM as the acceptor material. Devices fabricated from CF exhibit poor fill factor (FF) of 43%, low short-circuit current density (Jsc) of 6.86 mA/cm2, and moderate power conversion efficiency (PCE) of 2.4%, due to rapid evaporation of CF, leading to poor morphology of the active layer. When 0.3% DIO was added, the FF and Jsc were improved to 60% and 8.49 mA/cm2, respectively, because of the better film morphology. Active layer spin-coated from the high-boiling-point solvent of o-DCB shows better phase separation than that from CF, because of the slow drying nature of o-DCB, offering sufficient time for the self-organization of active-layer. Finally, using o-DCB as the parent solvent and 0.7% DIO as the cosolvent, we obtained optimized devices with continuous interpenetrating network films, affording a Jsc of 11.86 mA/cm2, an open-circuit voltage (Voc) of 0.72 V, an FF of 62%, and a PCE of 5.29%. This PCE is, to the best of our knowledge, the highest efficiency reported to date for devices prepared from the solution-processed DPP-based small molecules.

The phenomenon of ordered pattern formation is universal in nature but involves complex non-equilibrium processes that are highly important for both fundamental research and applied materials systems. Among countless pattern systems, a snowflake is possibly the most fascinating example offered by nature. Here, we report that single-layered and single-crystalline graphene flakes (GFs) with highly regular and hexagonal symmetric patterns can be grown on a liquid copper surface using a CH4 chemical vapor deposition (CVD) method. The different morphologies of these GFs can be precisely tailored by varying the composition of the inert gas/H2 carrier gas mixture used to produce the GFs, and the GF edges can be continuously tuned over the full spectrum from negative to zero to positive curvature in a controllable way. The family of GF crystal patterns is remarkably analogous to that of snowflakes, representing an ideal two-dimensional (2D) growth system. Pattern formations from compact to dendritic GFs can be explained by the continuous modulation of the competition between adatom diffusion along island edges or corners and surface diffusion processes. The formation of specific patterns during the growth of materials is both intriguing from a fundamental perspective and useful for practical applications. A team of researchers in China, led by Yunqi Liu, have now described the controlled formation of snowflake-like crystals of graphene — the one-atom-thick layer of carbon atoms that has attracted a great deal of attention across the scientific and technology communities in recent years. The highly regular and symmetric graphene flakes were grown by chemical vapor deposition: gaseous methane was transported over a liquid copper surface by means of a carrier gas (a mixture of hydrogen and an inert gas, argon or helium). The resulting single-layer, single-crystal flakes exhibited snowflake-like patterns that can be controlled by tuning the composition of the carrier gas. These chiseled structures are not only aesthetically appealing, but also represent an attractive platform for studying growth and nucleation processes and exploring structure–property relationships. We report that single-layered and single-crystalline graphene flakes (GFs) with highly regular and hexagonal symmetric patterns can be grown on a liquid copper surface using a CH4 chemical vapor deposition (CVD) method. Different morphologies of these GFs can be precisely tailored by varying the composition of inert gas/H2 carrier gas mixture, and the GF edges can be continuously tuned over the full spectrum from negative to zero to positive curvature in a controllable way. This study provides a well-behaved two-dimensional crystal growth system mimicking snowflakes, opening rich opportunities for engineering graphene patterns and studying graphene structure/property relationships.

Taking advantage of the “coffee-ring” effect, graphene electrodes with channel lengths as low as 1−2 micrometers are patterned by inkjet printing. Organic thin film transistors and complementary inverters are also fabricated using these graphene electrodes and show excellent performance. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

A novel reducing reagent, Lawesson's reagent (LR), is used to directly reduce graphene oxide (GO) films and single GO sheets. The as-prepared reduced graphene oxide (GOLR) is fully characterized by XPS, Raman, FTIR, 13C NMR and XRD. Most of the oxygen-containing groups are efficiently removed by LR and the conjugated graphene networks are restored. Highly conductive GOLR films and sheets are obtained. As a proof of concept, thin film field-effect transistors based on pentacene using patterned GOLR films as electrodes are fabricated and show high performances. Common cotton threads coated with GOLR can be used as flexible connecting wires to illuminate commercial light-emitting diodes. After low temperature annealing, such as 300 °C, higher conductivity and mobility of GOLR are obtained due to the removal of additional oxygen groups and better ordering of graphene sheets.

By employing a diabatic model and a first-principle direct method, we have investigated the carrier transport properties of the highly efficient organic light-emitting materials 1,1,2,3,4,5-hexaphenylsilole (HPS) and 1-methyl-1,2,3,4,5-pentaphenylsilole (MPPS). The electronic coupling constants and reorganization energies are calculated for a wide variety of nearest-neighbor charge transfer pathways. The theoretical calculations show that (i) the electron mobility is very close to that of the hole, which indicates a balanced carrier transport in these materials, and (ii) the carrier mobilities for MPPS are larger than those for HPS. These results help explain the underlying microscopic mechanism for the high electroluminescence efficiency.

With the advances of organic field-effect transistors (OFETs), the interface between semiconductors and dielectrics has received much attention due to its dramatic effects on the morphology and charge-transport of organic semiconductors in OFETs. The purpose of this review is to give an overview of the recent progress in the engineering of the dielectric–semiconductor interface in OFETs. The interface-dependent performances of OFETs are reviewed, and interfacial control methods are especially dealt with an aim to solve interfacial effects. Finally, novel applications of the dielectric–semiconductor interface for achieving multifunctions are summarized to offer a clear map of interface engineering in OFETs.

Advanced MaterialsVolume 20, Issue 8 p. 1511-1515 Communication High-Performance Air-Stable Bipolar Field-Effect Transistors of Organic Single-Crystalline Ribbons with an Air-Gap Dielectric† Qingxin Tang, Qingxin Tang Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China) Graduate School of Chinese Academy of Sciences Beijing 100039 (P.R. China)Search for more papers by this authorYanhong Tong, Yanhong Tong Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China)Search for more papers by this authorHongxiang Li, Corresponding Author Hongxiang Li lhx@iccas.ac.cn Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China)Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China).Search for more papers by this authorZhuoyu Ji, Zhuoyu Ji Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China) Graduate School of Chinese Academy of Sciences Beijing 100039 (P.R. China)Search for more papers by this authorLiqiang Li, Liqiang Li Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China) Graduate School of Chinese Academy of Sciences Beijing 100039 (P.R. China)Search for more papers by this authorWenping Hu, Corresponding Author Wenping Hu huwp@iccas.ac.cn Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China)Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China).Search for more papers by this authorYunqi Liu, Yunqi Liu Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China)Search for more papers by this authorDaoben Zhu, Daoben Zhu Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China)Search for more papers by this author Qingxin Tang, Qingxin Tang Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China) Graduate School of Chinese Academy of Sciences Beijing 100039 (P.R. China)Search for more papers by this authorYanhong Tong, Yanhong Tong Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China)Search for more papers by this authorHongxiang Li, Corresponding Author Hongxiang Li lhx@iccas.ac.cn Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China)Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China).Search for more papers by this authorZhuoyu Ji, Zhuoyu Ji Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China) Graduate School of Chinese Academy of Sciences Beijing 100039 (P.R. China)Search for more papers by this authorLiqiang Li, Liqiang Li Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China) Graduate School of Chinese Academy of Sciences Beijing 100039 (P.R. China)Search for more papers by this authorWenping Hu, Corresponding Author Wenping Hu huwp@iccas.ac.cn Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China)Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China).Search for more papers by this authorYunqi Liu, Yunqi Liu Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China)Search for more papers by this authorDaoben Zhu, Daoben Zhu Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing 100080 (P.R. China)Search for more papers by this author First published: 21 April 2008 https://doi.org/10.1002/adma.200702145Citations: 134 † The authors acknowledge financial support from the National Natural Science Foundation of China (20421101, 20404013, 20571079, 50725311), the Ministry of Science and Technology of China (2006CB806200, 2006CB932100), and the Chinese Academy of Sciences. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract High-performance bipolar OFETs are fabricated using single-crystalline sub-micrometer-sized ribbons of CuPc and F16CuPc and the technique of an air-gap dielectric. Their similar energy levels to the work function of the Au electrodes, the high mobility of their single crystals, and the great advantages of the air-gap dielectric result in a high performance of the bipolar devices. The devices show excellent air-stable characteristics with electron and hole mobilities as high as 0.17 and 0.1 cm2 V−1 s−1, respectively. Citing Literature Volume20, Issue8April 21, 2008Pages 1511-1515 RelatedInformation

Abstract A series of fluorene‐based oligomers with novel spiro‐annulated triarylamine structures, namely DFSTPA, TFSTPA, and TFSDTC, are synthesized by a Suzuki cross‐coupling reaction. The spiro‐configuration molecular structures lead to very high glass transition temperatures (197–253 °C) and weak intermolecular interactions, and consequently the structures retain good morphological stability and high fluorescence quantum efficiencies(0.69–0.98). This molecular design simultaneously solves the spectral stability problems and hole‐injection and transport issues for fluorene‐based blue‐light‐emitting materials. Simple double‐layer electroluminescence (EL) devices with a configuration of ITO/TFSTPA (device A) or TFSDTC (device B)/ TPBI/LiF/Al, where TFSTPA and TFSDTC serve as hole‐transporting blue‐light‐emitting materials, show a deep‐blue emission with a peak around 432 nm, and CIE coordinates of (0.17, 0.12) for TFSTPA and (0.16, 0.07) for TFSDTC, respectively, which are very close to the National Television System Committee (NTSC) standard for blue (0.15, 0.07). The maximum current efficiency/external quantum efficiencies are 1.63 cd A −1 /1.6% for device A and 1.91 cd A −1 /2.7% for device B, respectively. In addition, a device with the structure ITO/DFSTPA/Alq 3 /LiF/Al, where DFSTPA acts as both the hole‐injection and ‐transporting material, is shown to achieve a good performance, with a maximum luminance of 14 047 cd m −2 , and a maximum current efficiency of 5.56 cd A −1 . These values are significantly higher than those of devices based on commonly used N , N ′‐di(1‐naphthyl)‐ N , N ′‐diphenyl‐[1,1′‐biphenyl]‐4,4′‐diamine (NPB) as the hole‐transporting layer (11 738 cd m −2 and 3.97 cd A −1 ) under identical device conditions.

Two series of polyurethanes (P1−P10) containing NLO chromophores as side chains were prepared, in which the size of isolation groups was changed from small atoms to much larger groups such as carbazolyl groups. The polymers were well characterized. The tested NLO properties of the polymers demonstrate that the NLO values and the poling efficiency of the polymers are not always improved with increasing of the size of isolation spacer, and for a given chromophore moiety, there is a suitable isolation group present to boost its microscopic β value to possibly higher macroscopic NLO property efficiently.