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The lack of ambipolar polymers with balanced hole (μh) and electron mobilities (μe) >10 cm2 V−1 s−1 is the main bottleneck for developing organic integrated circuits. Herein, we show the design and synthesis of a π‐extended selenium‐containing acceptor‐dimeric unit, namely benzo[c][1,2,5]selenadiazol‐4‐yl)ethane (BBSeE), to address this dilemma. In comparison to its sulfur‐counterpart, BBSeE demonstrates enlarged co‐planarity, selective noncovalent interactions, polarized Se−N bond, and higher electron affinity. The successful stannylation of BBSeE offers a great opportunity to access acceptor‐acceptor copolymer pN‐BBSeE, which shows a narrower band gap, lower‐lying lowest unoccupied molecular orbital level (−4.05 eV), and a higher degree of backbone planarity. Consequently, the pN‐BBSeE‐based organic transistors display an ideally balanced ambipolar transporting property with μh and μe of 10.65 and 10.72 cm2 V−1 s−1, respectively. To the best of our knowledge, the simultaneous μh/μe values >10.0 cm2 V−1 s−1 are the best performances ever reported for ambipolar polymers. In addition, pN‐BBSeE shows an excellent shelf‐storage stability, retaining over 85 % of the initial mobility values after two months storage. Our study demonstrates the π‐extended acceptor‐dimeric BBSeE is a promising acceptor building block for constructing high‐performance ambipolar polymers applied in next‐generation organic integrated circuit. [ABSTRACT FROM AUTHOR]

The lack of ambipolar polymers with balanced hole (μh) and electron mobilities (μe) >10 cm2 V−1 s−1 is the main bottleneck for developing organic integrated circuits. Herein, we show the design and synthesis of a π‐extended selenium‐containing acceptor‐dimeric unit, namely benzo[c][1,2,5]selenadiazol‐4‐yl)ethane (BBSeE), to address this dilemma. In comparison to its sulfur‐counterpart, BBSeE demonstrates enlarged co‐planarity, selective noncovalent interactions, polarized Se−N bond, and higher electron affinity. The successful stannylation of BBSeE offers a great opportunity to access acceptor‐acceptor copolymer pN‐BBSeE, which shows a narrower band gap, lower‐lying lowest unoccupied molecular orbital level (−4.05 eV), and a higher degree of backbone planarity. Consequently, the pN‐BBSeE‐based organic transistors display an ideally balanced ambipolar transporting property with μh and μe of 10.65 and 10.72 cm2 V−1 s−1, respectively. To the best of our knowledge, the simultaneous μh/μe values >10.0 cm2 V−1 s−1 are the best performances ever reported for ambipolar polymers. In addition, pN‐BBSeE shows an excellent shelf‐storage stability, retaining over 85 % of the initial mobility values after two months storage. Our study demonstrates the π‐extended acceptor‐dimeric BBSeE is a promising acceptor building block for constructing high‐performance ambipolar polymers applied in next‐generation organic integrated circuit. [ABSTRACT FROM AUTHOR]

A series of new π‐conjugated macrocycles (AzoM‐n‐E, n = 1–3) incorporating azobenzene units have been synthesized by a facile strategy in one‐pot reaction. The resultant azobenzene‐embedded macrocycles feature intrinsic photoresponsive behaviors and intriguing supramolecular assembling properties. The smallest macrocycle AzoM‐1‐E with a rigid planar conjugated backbone structure is used to prepare the single crystal transistors, showing reversible optical tunability. The moderate size macrocycle AzoM‐2‐E assembles into a dimer in the form of interpenetration through π‐π stacking between azobenzene units. The largest macrocycle AzoM‐3‐E with enhanced flexibility can adaptively assemble with various types of electron‐deficient guests accompanied by distortion of azobenzene. Typically, AzoM‐3‐E assembles with the planar F4‐TCNQ to form a tetragonal geometry by C‐F···π and π‐π interactions, while the assembly with ellipsoidal C70 via π‐π interactions induces AzoM‐3‐E to form a boat‐shaped geometry. This work will shed new light on the development of functional conjugated macrocycles in organic electronics. [ABSTRACT FROM AUTHOR]

Biomarkers are primary indicators for precise diagnosis and treatment. The early identification of health biomarkers has been sustained by the evolutionary success in sensor technologies. Among them, graphene field‐effect transistor (GFET) biosensors have exhibited major advantages such as an ultrashort response time, high sensitivity, easy operation, capability of integration, and label‐free detection. Owing to the atomic thickness, graphene restricts charge carrier flow merely at the material surface and responds to foreign stimuli directly, leading to effective signal acquisition and transmission. Here, this review summarizes the latest advances in GFET biosensors in a comprehensive manner that contains the device design, working principle, surface functionalization, and proof‐of‐concept applications. It provides a comprehensive survey of GFET biosensors with regard to biomarker analysis at the single‐device level and integrated prototypes that include wearable sensors, biomimetic systems, healthcare electronics, and diagnostic platforms. Moreover, there is discussion on the long‐standing research efforts and outlook for the future development of GFET sensor systems from lab to fab. [ABSTRACT FROM AUTHOR]

For epidemic prevention and control, molecular diagnostic techniques such as field‐effect transistor (FET) biosensors is developed for rapid screening of infectious agents, including Mycobacterium tuberculosis, SARS‐CoV‐2, rhinovirus, and others. They obtain results within a few minutes but exhibit diminished sensitivity (<75%) in unprocessed biological samples due to insufficient recognition of low‐abundance analytes. Here, an electro‐enhanced strategy is developed for the precise detection of trace‐level infectious agents by liquid‐gate graphene field‐effect transistors (LG‐GFETs). The applied gate bias preconcentrates analytes electrostatically at the sensing interface, contributing to a 10‐fold signal enhancement and a limit of detection down to 5 × 10−16 g mL−1 MPT64 protein in serum. Of 402 participants, sensitivity in tuberculosis, COVID‐19 and human rhinovirus assays reached 97.3% (181 of 186), and specificity is 98.6% (213 of 216) with a response time of <60 s. This study solves a long‐standing dilemma that response speed and result accuracy of molecular diagnostics undergo trade‐offs in unprocessed biological samples, holding unique promise in high‐quality and population‐wide screening of infectious diseases. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Organic field‐effect transistor (OFET)‐based circuits require stable device performance. However, OFETs are suffering from process variation and environmental instability, which limits circuit performance. Here, an optimally designed XOR gate based on p‐type‐only OFETs is reported. The circuit has excellent postfabrication tunability that is enough to cope with a threshold voltage shift as high as 1.5 V. Moreover, the circuit largely reduces the number of transistors by 81% compared with conventional design and can realize ultralow power consumption. In addition, the XOR gate can act as a programmable inverter with good regenerative property. Utilizing the XOR gate, the authors demonstrate its application in cryptography. A 3481‐bit message is correctly encrypted and decrypted with an accuracy rate of up to 98.5%. The authors' work enables the accurate prediction of circuit operation in the presence of OFET threshold voltage shifts. [ABSTRACT FROM AUTHOR]

Bioinspired electronics have shown great potential in the field of artificial intelligence and brain‐like science. Low energy consumption and multifunction are key factors for its application. Here, multisensory artificial synapse and neural networks based on electrolyte‐gated vertical organic field‐effect transistors (VOFETs) are first developed. The channel length of the organic transistor is scaled down to 30 nm through cross‐linking strategy. Owing to the short channel length and extremely large capacitance of the electric double layer formed at the electrolyte–channel interface, the minimum power consumption of one synaptic event is 0.06 fJ, which is significantly lower than that required by biological synapses (1–10 fJ). Moreover, the artificial synapse can be trained to learn and memory images in a 5 × 5 synapse array and emulate the human brain's spatiotemporal information processing and sound azimuth detection. Finally, the artificial tongue is designed using the synaptic transistor that can discriminate acidity. Overall, this study provides new insights into realizing energy‐efficient artificial synapses and mimicking biological sensory systems. [ABSTRACT FROM AUTHOR]

Ambipolar polymer semiconductors are potentially serviceable for logic circuits, light-emitting field-effect transistors (LFETs) and polymer solar cells (PSCs). Although several high-performance ambipolar polymers have been developed, their optoelectronic devices are generally processed from toxic chlorinated solvents. To achieve the commercial applications of organic FETs (OFETs), the polymers should be processed from nonchlorinated solvents, instead of chlorinated solvents. However, most conjugated polymers show poor solubility in nonchlorinated solvents. It is of great importance to develop ambipolar polymers that can be processed from nonchlorinated solvents. Here, we develop a nonchlorinated solvent processed polymer named poly[7-fluoro-N, N′-di(4-decyltetradecyl)-7′-azaisoindigo-6′,6″-(thieno[3,2-b]thiophene-2,5-diyl)-7‴-fluoro-N″, N‴-di(4-decyltetradecyl)-7″-azaisoindigo-6,6‴-([2,2″-bithiophene]-5,5″-diyl)] (PITTI-BT) by designing a monomer with a large molar mass. The polymer displays good solubility in p-xylene (PX). Well-aligned films of PITTI-BT are achieved by an off-center spin-coating (SC) method. Based on the high-quality films, the OFETs fabricated from PX solution achieve record ambipolar performance with hole and electron mobilities of 3.06 and 2.81 cm2 V−1 s−1, respectively. The combination of nonchlorinated solvents and good alignment process offers an effective and eco-friendly approach to obtain high-performance ambipolar transistors. [ABSTRACT FROM AUTHOR]

The solution‐handling characteristics of π‐conjugated polymer semiconductors make them promising candidates for low‐cost flexible electronics. Although homogeneous and stable nonchlorine solvent (NClS) processing is the only way that must be passed for future application, polymer semiconductors still meet the challenges of poor solubility and inhomogeneities in NClS. Here, the authors primp polymer molecules with protonic acid by multiple interactions, that is, proton exchange and hydrogen bond interaction, to achieve scale and model‐constrained PDVT‐10c assembly in NClS. As a result, a uniform near‐amorphous PDVT‐C10c film is developed for polymer thin‐film transistor (PTFT) array, which exhibits uniform performance with much narrower Gaussian standards deviation than pristine PDVT‐C10c one. Finally, a 5 cm × 5 cm PTFT as the active‐matrix circuit for blue organic light‐emitting diode is demonstrated. The results illustrate the great potential of protonic acid‐mediated molecular self‐assembly on homogeneous and stable NClS processing polymer semiconductors for next‐generation flexible electronics. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The cornerstones of emerging high-performance organic photovoltaic devices are bulk heterojunctions, which usually contain both structure disorders and bicontinuous interpenetrating grain boundaries with interfacial defects. This feature complicates fundamental understanding of their working mechanism. Highly-ordered crystalline organic p–n heterojunctions with well-defined interface and tailored layer thickness, are highly desirable to understand the nature of organic heterojunctions. However, direct growth of such a crystalline organic p–n heterojunction remains a huge challenge. In this work, we report a design rationale to fabricate monolayer molecular crystals based p–n heterojunctions. In an organic field-effect transistor configuration, we achieved a well-balanced ambipolar charge transport, comparable to single component monolayer molecular crystals devices, demonstrating the high-quality interface in the heterojunctions. In an organic solar cell device based on the p–n junction, we show the device exhibits gate-tunable open-circuit voltage up to 1.04 V, a record-high value in organic single crystalline photovoltaics. Realizing organic p–n junctions based on ordered crystalline materials with dimensions comparable to the exciton diffusion length of most organic semiconductors remains a challenge. Here, the authors report a strategy to form molecular monolayer crystal-based p–n junctions with thickness below 5 nm. [ABSTRACT FROM AUTHOR]

A heterocycloarene derivative (S-Octulene) possessing two sulfur atoms was conveniently synthesized through Bi(OTf)3-catalyzed cyclization from a macrocyclic tetramethoxyethenylated precursor. The physical properties of S-Octulene and its supramolecular host–guest interaction with C60 and C70 were investigated by fluorescence titration and 1H NMR. The solution-processed organic field-effect transistor (OFET) measurements demonstrated that S-Octulene behaved as a p-type semiconductor with a hole mobility exceeding 0.01 cm2 V−1 s−1. Our findings pave a new path to design novel heterocycloarenes for the development of host–guest chemistry and organic semiconductors. [ABSTRACT FROM AUTHOR]

Graphene has attracted great interest in the past decade due to its unique band structure and physical properties such as quantum electronic transport, extremely high mobility, high elasticity and optical properties. Graphene is generally obtained by mechanical exfoliation, epitaxial growth, chemical vapor deposition and chemical synthesis approaches, wherein the reduction of graphene oxide (GO) is a practical approach to synthesize large‐scale graphene. Via reduction, highly conductive reduced graphene oxide (RGO) can be obtained, which has electrical and optical properties analogous to those of graphene. However, Field‐effect transistors (FETs) based RGO typically exhibit p‐type in ambient rather than the ambipolar behavior of intrinsic graphene, due to the doping effect induced by substrate and the air. Meanwhile, large hysteresis accompanies with the p‐type transistor. Here, a self‐assembled monolayer (SAM) of octadecyltrichlorosilane (OTS)‐RGO heterostructure is developed, in which RGO is sandwiched between OTS SAMs. The heterostructure passivates the RGO device and eliminates the doping of graphene from the surroundings. The obtained RGO FETs exhibit air‐stable symmetric ambipolar behavior with Dirac point at 0 V gate voltage and negligible hysteresis. This approach will also be applicable to pristine graphene and other two‐dimensional materials to obtain the intrinsic properties under ambient conditions, thereby promoting the research and applications of two‐dimensional materials. Monolayer of octadecyltrichlorosilane (OTS) is successfully self‐assembled on the surface of reduced graphene oxide (RGO), and RGO‐OTS SAM heterostructure is fabricated for FET devices, which exhibits air stable intrinsic symmetric ambipolar field‐effect behavior with the Dirac point at the 0 V gate voltage and negligible hysteresis. [ABSTRACT FROM AUTHOR]

Many high-performance solution-processable polymer thin-film transistors (PTFTs) have been reported. This contribution presents a comparative study of oriented films that have been deposited by means of solution shearing (SS) with charge-carrier transport anisotropy for PTFTs based on a diketopyrrolopyrrole-thiazolothiazole donor-acceptor copolymer (PDPPTzBT). The maximum field-effect mobility of the SS film of PDPPTzBT was 10.00 cm2 V−1 s. We also blended a solution of PDPPTzBT with a solution of polystyrene (PS). Solvent vapor annealing (SVA) lateral phase separation was adopted to block carrier transport in the direction of π-π stacking, and further evidence of charge transport anisotropy was provided. Highly oriented polymer films will further influence the carrier transport anisotropy and promote carrier transport along the backbone, and the performance of the field-effect transistor is thus improved. [ABSTRACT FROM AUTHOR]

'Regioselectivity deposition' method is developed to pattern silver electrodes facilely and efficiently by solution-process with high resolution (down to 2 μm) on different substrates in A4 paper size. With the help of this method, large-area, flexible, high-performance polymer field-effect transistors based on the silver electrodes and polyimide insulator are fabricated with bottom-contact configuration by all-solution processes. The polymer devices exhibit high performance with average field-effect mobility over 1.0 cm2 V−1 s−1 (the highest mobility up to 1.5 cm2 V−1 s−1) and excellent environmental stability and flexibility, indicating the cost effectiveness of this method for practical applications in organic electronics. [ABSTRACT FROM AUTHOR]

The lack of ambipolar polymers with balanced hole (μh) and electron mobilities (μe) >10 cm2 V−1 s−1 is the main bottleneck for developing organic integrated circuits. Herein, we show the design and synthesis of a π‐extended selenium‐containing acceptor‐dimeric unit, namely benzo[c][1,2,5]selenadiazol‐4‐yl)ethane (BBSeE), to address this dilemma. In comparison to its sulfur‐counterpart, BBSeE demonstrates enlarged co‐planarity, selective noncovalent interactions, polarized Se−N bond, and higher electron affinity. The successful stannylation of BBSeE offers a great opportunity to access acceptor‐acceptor copolymer pN‐BBSeE, which shows a narrower band gap, lower‐lying lowest unoccupied molecular orbital level (−4.05 eV), and a higher degree of backbone planarity. Consequently, the pN‐BBSeE‐based organic transistors display an ideally balanced ambipolar transporting property with μh and μe of 10.65 and 10.72 cm2 V−1 s−1, respectively. To the best of our knowledge, the simultaneous μh/μe values >10.0 cm2 V−1 s−1 are the best performances ever reported for ambipolar polymers. In addition, pN‐BBSeE shows an excellent shelf‐storage stability, retaining over 85 % of the initial mobility values after two months storage. Our study demonstrates the π‐extended acceptor‐dimeric BBSeE is a promising acceptor building block for constructing high‐performance ambipolar polymers applied in next‐generation organic integrated circuit. [ABSTRACT FROM AUTHOR]

The lack of ambipolar polymers with balanced hole (μh) and electron mobilities (μe) >10 cm2 V−1 s−1 is the main bottleneck for developing organic integrated circuits. Herein, we show the design and synthesis of a π‐extended selenium‐containing acceptor‐dimeric unit, namely benzo[c][1,2,5]selenadiazol‐4‐yl)ethane (BBSeE), to address this dilemma. In comparison to its sulfur‐counterpart, BBSeE demonstrates enlarged co‐planarity, selective noncovalent interactions, polarized Se−N bond, and higher electron affinity. The successful stannylation of BBSeE offers a great opportunity to access acceptor‐acceptor copolymer pN‐BBSeE, which shows a narrower band gap, lower‐lying lowest unoccupied molecular orbital level (−4.05 eV), and a higher degree of backbone planarity. Consequently, the pN‐BBSeE‐based organic transistors display an ideally balanced ambipolar transporting property with μh and μe of 10.65 and 10.72 cm2 V−1 s−1, respectively. To the best of our knowledge, the simultaneous μh/μe values >10.0 cm2 V−1 s−1 are the best performances ever reported for ambipolar polymers. In addition, pN‐BBSeE shows an excellent shelf‐storage stability, retaining over 85 % of the initial mobility values after two months storage. Our study demonstrates the π‐extended acceptor‐dimeric BBSeE is a promising acceptor building block for constructing high‐performance ambipolar polymers applied in next‐generation organic integrated circuit. [ABSTRACT FROM AUTHOR]

Abstract Organic field-effect transistors (OFETs) have received significant interest due to potential applications from low-cost active circuit to wearable health care devices. Organic semiconductors as one of the key components in OFETs have drawn great attentions during last decades. Among them, antiaromatic and quinoidal materials have become the most intensively studied semiconductors. Therefore, this review describes the chemical structures and efficiency characteristics of π-conjugated materials through antiaromaticity and quinoid strategy for OFETs. In addition, rational designs and synthetic methods for these materials will be summarized, and a practical guideline for accelerating the development of high-performance semiconducting materials and devices will be provided. [ABSTRACT FROM AUTHOR]

Small reaction, big application! The silver mirror reaction is a straightforward way to produce silver films, and can be performed using cheap reactants in aqueous solutions. Here, it is successfully introduced into organic electronics by L. Jiang, H. Dong, G. Yu, W. Hu, and co‐workers, and applied to the process of fabricating flexible, high‐performance, large‐area, all‐solution‐processable organic fieldeffect transistors at room temperature with high resolution. [ABSTRACT FROM AUTHOR]

Thiophene oligomers end-capped with phenyl-1H-pyrrole were used as active layers of organic field-effect transistors. Two types of cores that vary in size and shape of α-linked thiophenes and fused-ring thiophenes were chosen to study the structure-property relationship. The crystal structures, optical, electrochemical and electronic properties were investigated, and the heterocyclic compounds exhibited clear p-type semiconducting behavior. A new series of phenyl-1H-pyrrole end-capped thiophene oligomers has been synthesized, and the relationships between the molecular structures and electronic properties were investigated. As the semiconductors are in organic thin-film transistors, they all show good p-type organic thin-film transistor properties. [ABSTRACT FROM AUTHOR]

Organic thin-film transistor (OTFT) has attracted considerable research interest in the past decades because of its great potential on flexible electronic applications. So far, there is still a big challenge to integrate high electrical properties and mechanical bending stability in single OTFT via a simple approach. A type of dielectric material possessing excellent flexibility, insulating property, compatibility with multiple organic semiconductors, and easy maneuverability are desirable. In this letter, the OTFT based on polyphenyleneoxide (PPO) dielectric, selected out from 10 different kinds of common polymers, shows invariant high mobility of around 1.5 cm2/Vs even after 5000-times mechanical bending with a small bending radius of merely 4 mm. Whereas the mobilities of OTFTs based on other polymeric dielectrics, such as PS and PMMA, obviously decrease within 100-times bending. Subsequently, flexible oscillators have also been fabricated based on PPO dielectric, which show negligible change on electrical performance after 500-times mechanical bending. Image 10574 • Novel polymeric dielectrics are employed to fabricate flexible transistors and oscillators. • Organic transistors show constant high mobility even after 5000-times bending. • Organic oscillators can bend to 4 mm for 500-times without performance loss. • Easily prepared polymeric dielectric is very promise for flexible applications. [ABSTRACT FROM AUTHOR]

Abstract: The authors report on low operation voltage memory cells based on heterojunction ambipolar organic transistors with polymer gate electret (PGE). The introduction of the N,N′-dioctyl perylene diimide/pentacene heterojunction into the memory OFETs with PGE successfully lowered the memory cells’ reading, writing and erasing programmed voltages (reading voltage of 2V, writing and erasing programmed voltages of 10V). Meanwhile, the memory devices showed reproducible and durable memory behavior in more than 500 cycles’ testing. The built-in electric field-effect at heterojunction surface should efficiently reduce operation voltage of the memory devices. [Copyright &y& Elsevier]

Abstract: Two new D-π-A molecules 1 and 2 were prepared from the reaction between the Fisher’s base and 7,7,8,8-tetracyano-p-quinodi-methane (TCNQ)/tetracyanoethylene (TCNE). OFETs with the thin-films of 1 and 2 as the active layers (semiconductors) were fabricated. These OFETs show relatively high mobility (up to 10−2 cm2 V−1 s−1) and on/off ratio (up to 105). In particular, these OFETs have rather low threshold voltages. [Copyright &y& Elsevier]

Abstract: Field-effect transistors using cyclo[6]pyrrole as active layers were prepared by Langmuir-Blodgett (LB) method. Cyclo[6]pyrrole is a porphyrin analogue with an extended π-system(22-π-electron). It could form a stable, reproducible monolayer at the air–water interface, which could be transferred onto a substrate with nearly unity transfer ratio and resulted in multilayer structure with the cyclo[6]pyrrole molecules stacking in a face-to-face configuration due to strong intermolecular π–π interactions. An un-optimized device based on this LB films displayed a mobility of 0.014cm2 V−1 s−1, which is higher than the highest value of the devices based on typical porphyrins reported. [Copyright &y& Elsevier]