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Inspired by the previous machine‐learning study that the number of hydrogen‐bonding acceptor (NHBA) is important index for the hole mobility of organic semiconductors, seven dithienobenzothiazole (DBT) derivatives 1 a–g (NHBA=5) were designed and synthesized by one‐step functionalization from a common precursor. X‐ray single‐crystal structural analyses confirmed that the molecular arrangements of 1b (the diethyl and ethylthienyl derivative) and 1c (the di(n‐propyl) and n‐propylthienyl derivative) in the crystal are classified into brickwork structures with multidirectional intermolecular charge‐transfer integrals, as a result of incorporation of multiple hydrogen‐bond acceptors. The solution‐processed top‐gate bottom‐contact devices of 1b and 1c had hole mobilities of 0.16 and 0.029 cm2 V−1s−1, respectively. [ABSTRACT FROM AUTHOR]

The key roles of electrode/semiconductor and semiconductor/dielectric interfaces play in the ideality of organic field‐effect transistors (OFETs) by traditional device preparation technologies are not yet fully understood, which severely limits progress in the design of molecules, the understanding of transport mechanisms, and the circuit applications of OFETs. Herein, at a quantitative level, the origin of nonideal current–voltage (I–V) curves and possibly overestimated mobility in single‐crystal OFETs is revealed, including contact resistance (Rc), charge trapping, and scattering at interfaces of devices. Impressively, an efficient interface collaborative strategy, which consists of transferred “doped” electrodes with tunable contact “doping” localized regions at the source‐drain contacts and polymer‐modified SiO2 with suitable surface polarity (γsp) is further demonstrated that have great advantages in the construction of ideal high mobility devices. Also, an interesting double‐edged sword effect of γsp of dielectric on the ideality of OFETs is observed. The dielectric with a lower γsp can result in higher mobility, while too low γsp would degrade the device ideality due to significant effect of charge scattering. The findings not only provide new perspectives and strategies to construct ideal OFETs but also offer useful guidance to correctly evaluate organic semiconductor materials. [ABSTRACT FROM AUTHOR]

We report the synthesis of a longitudinally helical molecular nanocarbon, hexabenzoheptacene (HBH), along with its dimethylated derivative (HBH‐Me), which are composed of six benzene rings periodically benzannulated to both zigzag edges of a heptacene core. This benzannulation pattern endows the resulting nanocarbons with a helical heptacene core and local aromaticity, imparting enhanced solubility and stability to the system. The chiral HBH‐Me adopts a more highly twisted conformation with an end‐to‐end twist angle of 95°, enabling the separation of the enantiomers. Both HBH and HBH‐Me can be facilely oxidized into their corresponding dications, which exhibit enhanced planarity and aromaticity upon loss of electrons. Notably, both longitudinally helical nanocarbons readily promote solid state packing into two‐dimensional (2D) arrangement. Single‐crystal microbelts of HBH‐Me show hole mobility up to 0.62 cm2 V−1 s−1, illustrating the promising potential of these longitudinally helical molecules for organic electronic devices. [ABSTRACT FROM AUTHOR]

The rational development of organic electronic devices can greatly benefit from a molecular‐level description, where an accurate description of the Coulombic interactions among charge carriers holds paramount importance. However, the molecular‐level organic field‐effect transistor (OFET) simulations do not fully include the short‐range charge‐carrier Coulombic interactions, thus limiting their accuracy. Here, an efficient solution is demonstrated to the 3D Poisson's equation with mixed boundary conditions, optimized for integration into the simulations of organic electronic devices. It leverages the finite difference method for discretization, the Krylov subspace iterative methods for solving the linear system, the algebraic multigrid algorithm for preconditioning, and OpenMP and CUDA parallelization for acceleration. For the organic field‐effect transistors of micrometer sizes or smaller dimensions, obtaining the electric potential within the device takes less than 0.1 s, which is sufficiently efficient for molecular‐level modeling. As a result, both short‐ and long‐range electrostatic interactions are successfully incorporated in the molecular‐level modeling of OFET devices. This integration significantly enhances the robustness of OFET modeling for future applications. [ABSTRACT FROM AUTHOR]

P-type Organic Semiconductors, TQx5-BT-DPP8 (1a) and TQx5-BT-DPP20 (1b), consisting of a donor unit of bithiophene (BT) and two acceptor units of thiadiazole quinoxaline (TQx) and diketopyrrolopyrrole (DPP), were synthesized, and their electronic states and physical properties were elucidated. These semiconductors demonstrate strong absorption extending from the visible to the near-infrared region, functioning effectively as strong donor dyes. The organic field-effect transistors (OFETs) exhibited normally on transistor characteristics, with carrier mobilities of 1.1 x 10-3 cm²/Vs for 1a and 3.3 x 10-4 cm²/Vs for 1b. [ABSTRACT FROM AUTHOR]

Unsymmetric organic semiconductors have many advantages such as good solubility, rich intermolecular interactions for potential various optoelectronic applications. However, their synthesis is more challenging due to intricate structures thus normally suffering tedious synthesis. Herein, we report a trisulfur radical anion (S3⋅−) triggered domino thienannulation strategy for the synthesis of dibenzo[d,d′]thieno[2,3‐b;4,5‐b′]dithiophenes (DBTDTs) using readily available 1‐halo‐2‐ethynylbenzenes as starting materials. This domino protocol features no metal catalyst and the formation of six C−S and one C−C bonds in a one‐pot reaction. Mechanistic study revealed a unique domino radical anion pathway. Single crystal structure analysis of unsymmetric DBTDT shows that its unique unsymmetric structure endows rich and multiple weak S⋅⋅⋅S interactions between molecules, which enables the large intermolecular transfer integrals of 86 meV and efficient charge transport performance with a carrier mobility of 1.52 cm2 V−1 s−1. This study provides a facile and highly efficient synthetic strategy for more high‐performance unsymmetric organic semiconductors. [ABSTRACT FROM AUTHOR]

Self‐assembled monolayers (SAMs) are a class of quasi‐2D materials adhesive to the substrate by chemisorption. Due to their transparency, diversity, stability, sensitivity, selectivity, and great potential in surface passivation, SAMs have been extensively investigated and applied in various functional devices, particularly in organic field effect transistors (OFETs). Among all the processing methods, kinetic‐driven spin‐coating is frequently used for the SAM preparation due to its high efficiency and low cost. However, the importance of SAM quality and its relationship to device performance has not been studied in detail, hindering the new SAM development and device optimization. In this study, SAMs prepared by kinetic‐driven spin‐coating are carefully investigated in terms of their surface morphology, density, and regularity, and proposed a correlation model between chemical structure and SAM quality. Additionally, the prepared SAMs are utilized as auxiliary layers on dielectrics and analyzed their effects on OFET properties. Through these investigations, a sequential relationship is established between chemical structure, SAM quality, and device performance, which can provide efficient feedback for system optimization. [ABSTRACT FROM AUTHOR]

Electrohydrodynamic (EHD) printing technique, which deposits micro/nanostructures through high electric force, has recently attracted significant research interest owing to their fascinating characteristics in high resolution (<1 μm), wide material applicability (ink viscosity 1–10 000 cps), tunable printing modes (electrospray, electrospinning, and EHD jet printing), and compatibility with flexible/wearable applications. Since the laboratory level of the EHD printed electronics' resolution and efficiency is gradually approaching the commercial application level, an urgent need for developing EHD technique from laboratory into industrialization have been put forward. Herein, we first discuss the EHD printing technique, including the ink design, droplet formation, and key technologies for promoting printing efficiency/accuracy. Then we summarize the recent progress of EHD printing in fabrication of displays, organic field‐effect transistors (OFETs), transparent electrodes, and sensors and actuators. Finally, a brief summary and the outlook for future research effort are presented. [ABSTRACT FROM AUTHOR]

Regioregular poly(3-hexylthio)thiopene (P3HTT) has emerged tremendous potential in organic electronic applications due to the strong noncovalent interactions from the sulfur atom linked to thiophene. However, P3HTT generally exhibits low charge mobility mostly due to poor solution processability attributed to dense arrangement of hexylthio side chain in polymer, which led to strong noncovalent interactions among sulfur atoms. To balance the nonvalent interaction and aggregation for P3HTT, herein, we systematically study the effect of hexylthio side chain content in polymer backbone on the structure and properties. A series of regioregular P3HTT-based homopolymers (P3HTT, P3HTT-50, P3HTT-33 and P3HTT-25) were prepared via Kumada catalyst transfer polycondensation method from a set of mono-, bi-, ter- and quarter-thiophenes containing different contents of hexylthio side chain. The DFT calculation shows the planarity of polymers backbone could be improved through reducing the density of hexylthio side chain in polymer mainchain. And significant changes in their crystallinity, aggregation and optical properties were observed with the content of hexylthio side chain reducing. The P3HTT-33 displayed the highest field-effect transistor hole mobility of 2.83×10−2 cm2·V−1·s−1 resulting from a balance between the crystallinity and planarity. This study demonstrates modulating the content of hexylthio side chain in P3HTT is an effective strategy to optimize the opto-electronic properties of polymer obtaining excellent semiconductor device performance. [ABSTRACT FROM AUTHOR]

Despite having an asymmetric structure, 2‐(thiopyran‐4‐ylidene)‐1,3‐benzodithiole (TP‐BT) is a good p‐type semiconductor containing isotropic three‐dimensional (3D) intermolecular interactions. Moreover, its π‐extended analogs can potentially work as organic electronic materials. Herein, a fused‐type π‐extended analog containing an extra benzene ring on the benzodithiole unit, i. e. 2‐(thiopyran‐4‐ylidene)‐1,3‐naphtho[2,3‐d]dithiole (TP‐NT), and three σ‐bonded‐type π‐extended analogs, i. e. phenyl‐, naphthyl‐, and anthryl‐substituted analogs (Ph‐TP‐BT, Nap‐TP‐BT, and Ant‐TP‐BT, respectively), were prepared and their molecular arrangements and organic field‐effect transistor (OFET) properties were investigated. TP‐NT formed a herringbone arrangement with 3D intermolecular interactions similar to that of the parent TP‐BT. Meanwhile, Ant‐TP‐BT formed a bilayer‐type layered herringbone arrangement. Since the highest occupied molecular orbital and the lowest unoccupied molecular orbital are located on the TP‐BT and anthracene units, respectively, a unique donor–acceptor separated network was formed. In OFETs prepared via a vapor deposition method using the σ‐bonded‐type analogs, slightly lower mobilities (0.1 to 8×10−3 cm2/Vs) than that of TP‐NT (0.1 cm2/Vs) were observed. Upon photo‐irradiation, the OFET of Ant‐TP‐BT exhibited a larger threshold voltage shift and an increase in the off current compared with TP‐NT. The σ‐bonded‐type analogs showed a larger photo‐response effect than TP‐NT derived from the donor–acceptor molecular structure. [ABSTRACT FROM AUTHOR]

In this work, numerical simulations are used to study ambipolar organic field-effect phototransistors, in which a spatially localized photoelectric effect can take place. This effect consists in the fact that there is a small spatially localized photosensitive region in the transistor channel, the position of which can be controlled by changing the gate voltage. The purpose of this work is to analyze the relationship between the form of the field dependence of the bound electron-hole pairs ( pairs) dissociation probability and characteristics of the studied ambipolar phototransistors such as normalized photocurrent, spatial resolution, and response time. It is shown that the optimal form of the field dependence of pairs dissociation probability is stepwise-like form, which can provide a high spatial resolution at high values of the normalized photocurrent without degrading the response time of the phototransistor. This shape can be achieved when the organic semiconductor has an extremely narrow distribution of pairs by size, described by the delta function. Also, using the example of several distributions of various shapes, it is shown that a decrease in the width of the distribution leads to an increase in the spatial resolution. Approaches to the selection and modification of organic semiconductor materials that would provide the most pronounced spatially localized photoelectric effect in ambipolar field-effect transistors are discussed. [ABSTRACT FROM AUTHOR]

Abstract Self‐assembled monolayers (SAMs) are a class of quasi‐2D materials adhesive to the substrate by chemisorption. Due to their transparency, diversity, stability, sensitivity, selectivity, and great potential in surface passivation, SAMs have been extensively investigated and applied in various functional devices, particularly in organic field effect transistors (OFETs). Among all the processing methods, kinetic‐driven spin‐coating is frequently used for the SAM preparation due to its high efficiency and low cost. However, the importance of SAM quality and its relationship to device performance has not been studied in detail, hindering the new SAM development and device optimization. In this study, SAMs prepared by kinetic‐driven spin‐coating are carefully investigated in terms of their surface morphology, density, and regularity, and proposed a correlation model between chemical structure and SAM quality. Additionally, the prepared SAMs are utilized as auxiliary layers on dielectrics and analyzed their effects on OFET properties. Through these investigations, a sequential relationship is established between chemical structure, SAM quality, and device performance, which can provide efficient feedback for system optimization.

Abstract Electrohydrodynamic (EHD) printing technique, which deposits micro/nanostructures through high electric force, has recently attracted significant research interest owing to their fascinating characteristics in high resolution (

In this study, we investigated the gas-sensing mechanism in bottom-gate organic field-effect transistors (OFETs) using poly(triarylamine) (PTAA). A comparison of different device architectures revealed that the top-contact structure exhibited superior gas-sensing performance in terms of field-effect mobility and sensitivity. The thickness of the active layer played a critical role in enhancing these parameters in the top-contact structure. Moreover, the distance and pathway for charge carriers to reach the active channel were found to significantly influence the gas response. Additionally, the surface treatment of the SiO2 dielectric with hydrophobic self-assembled mono-layers led to further improvement in the performance of the OFETs and gas sensors by effectively passivating the silanol groups. Under optimal conditions, our PTAA-based gas sensors achieved an exceptionally high response (>200%/ppm) towards NO2. These findings highlight the importance of device and interface engineering for optimizing gas-sensing properties in amorphous polymer semiconductors, offering valuable insights for the design of advanced gas sensors. [ABSTRACT FROM AUTHOR]

Introduction of asymmetric units into conjugated polymers is an important strategy to regulate the photophysical and electronic properties of polymers, as asymmetric units can not only regulate solubility and energy levels, but also molecular stacking and orientation, thus giving much higher optoelectronic properties. However, very few studies have been reported in this field. The semiconducting properties of conjugated polymers could be regulated through regioregularity adjustment. Here, we took the asymmetric thiophene/pyridine side group DPP as core and developed the regioregular monomer T-Py-DPP through three steps: alkyl chain introduction, tin monomer coupling and NBS double bromination. The T-Py-DPP monomer was polymerized into reg-PPyTDPP-2FBT with a head-to-head structure. The regioregularity of T-Py-DPP unit endowed reg-PPyTDPP-2FBT with backbone planarity, self-assembly orientation, network-like morphology and high crystallinity in films, thus the superior bipolar transport properties. The highest hole and electron mobilities of reg-PPyTDPP-2FBT were 0.93 and 0.57 cm2·V−1·s−1, respectively, with 40% improvement relative to the regiorandom polymer. [ABSTRACT FROM AUTHOR]

Polymer semiconductors are promising materials for stretchable, wearable, and implantable devices due to their intrinsic flexibility, facile functionalization, and solution processability at low temperatures. However, the crystalline domain of the conjugated structure for high charge carrier mobility in semiconducting polymers exhibits lower stretchability than that of the semi‐crystalline or amorphous domains. Herein, a set of thermoplastic soft semiconductors is synthesized with different ratios of diketopyrrolopyrrole–carbazole–diketopyrrolopyrrole (DPP‐Cz‐DPP)‐based hard segments and thiophene‐based aliphatic soft segments, having the similar structure of thermoplastic elastomers. The polymers exhibit decreased glassy temperatures with the increased content of the soft segments. The polymers show high crystallinity after copolymerization with a large‐sized DPP‐Cz‐DPP core and non‐conjugated segments due to an aggregation property of the conjugated core, still possessing a semi‐crystalline domain after annealing. The polymer films exhibit stretchability under strains of up to 60%. Organic field‐effect transistors fabricated using stretchable polymers show a mobility range of 0.125–0.005 cm2 V−1 s−1 with different proportions of the soft segment. The stretchability is improved significantly and the mobilities are decreased less when the content of the soft segment is increased. Therefore, this study presents a design principle for the development of a high‐performance stretchable semiconducting polymer. [ABSTRACT FROM AUTHOR]

Conjugated polymers with high charge mobilities have drawn increasing attention in organic field‐effect transistors (OFETs) in recent years. However, OFETs of conjugated polymers with high mobility and good device stability remain a challenge. In this article, we report a hyperbranched polymer approach to improve the charge mobility and device stability. Three hyperbranched diketopyrrolopyrrole‐based polymers were designed and synthesized via linear alkyl side‐chain linkers. The results show that 2D topological hyperbranched polymers form stable thin film microstructures, and thus improve the device stability, since the conjugated moiety is interconnected by linear alkyl chain. Besides, the incorporation of linear alkyl chain instead of branching alkyl one reduce steric hindrance, and improve the microstructure ordering as well as the charge mobility. Bar‐coated OFETs result demonstrates that the devices mobilities and operational stabilities (bias stability and bending resistance) are both improved. All these indicate that hyperbranched polymer is a potential candidate for future application. [ABSTRACT FROM AUTHOR]

Organic light emitting transistors (OLETs), which are used in optoelectronic devices, have progressed in recent years. Electroluminescence is a characteristic of organic light emitting diodes (OLEDs), and OLETs integrate OFET's synchronising processes with the OLEDs. OLETs are ideal for creating the next generation of displays because of their distinctive look. OLETs, the upgraded form of OLEDs, are attracting attention these days because of its architecture, flexibility, light weight, and low cost. This review specifically looks at the process of developing high-efficiency OLETs considering different OLET structures and optimizations. In this paper, various properties, behavior characteristics, and performance parameters are taken into account. Besides this, we also present a comparison between OLEDs and OLETs. Additionally, OLET performance is examined in terms of drive current, mobility, ON–OFF current ratios, and external quantum efficiency for single and multilayer designs. It is the goal of this study to emphasise and build a better knowledge of the future design of OLETs by analysing the existing state of the art. [ABSTRACT FROM AUTHOR]

The charge transport of planar organic field‐effect transistors (FETs) occurs in the nearest molecular layer to the dielectric layer. Therefore, organic monolayer FETs with two‐dimensional transport properties have been widely studied, and is considered to be promising for applications in bottom‐up integrated circuits. Based on the semiconducting polymer PffBT4T‐2DT, we fabricate the high‐performance monolayer FETs and unipolar inverters. Resultant polymer monolayer FETs exhibited excellent and uniform performance with a 107 on/off current ratio and ultra‐low leakage current with a magnitude of 10‐12 A. More importantly, the corresponding intrinsic gain of 1000 V/V is achieved, which surpass Si MOSFET. Zero‐VGS inverters based on these polymer monolayer FETs exhibit steep level transitions with a voltage gain of 70 V/V, which is among the record for inverters based on organic monolayer. [ABSTRACT FROM AUTHOR]

Abstract Polymer semiconductors are promising materials for stretchable, wearable, and implantable devices due to their intrinsic flexibility, facile functionalization, and solution processability at low temperatures. However, the crystalline domain of the conjugated structure for high charge carrier mobility in semiconducting polymers exhibits lower stretchability than that of the semi‐crystalline or amorphous domains. Herein, a set of thermoplastic soft semiconductors is synthesized with different ratios of diketopyrrolopyrrole–carbazole–diketopyrrolopyrrole (DPP‐Cz‐DPP)‐based hard segments and thiophene‐based aliphatic soft segments, having the similar structure of thermoplastic elastomers. The polymers exhibit decreased glassy temperatures with the increased content of the soft segments. The polymers show high crystallinity after copolymerization with a large‐sized DPP‐Cz‐DPP core and non‐conjugated segments due to an aggregation property of the conjugated core, still possessing a semi‐crystalline domain after annealing. The polymer films exhibit stretchability under strains of up to 60%. Organic field‐effect transistors fabricated using stretchable polymers show a mobility range of 0.125–0.005 cm2 V−1 s−1 with different proportions of the soft segment. The stretchability is improved significantly and the mobilities are decreased less when the content of the soft segment is increased. Therefore, this study presents a design principle for the development of a high‐performance stretchable semiconducting polymer.

Field-effect transistors based on organic semiconducting materials (OFETs) have unique advantages of intrinsically mechanical flexibility, simple preparation process, low manufacturing cost, and large-area preparation. Through the innovation of new material design and device structures, the performance of device parameters such as mobility, on–off current ratio, and the threshold voltage (VTH) of OFETs continues to improve. However, the VTH shift of OFETs has always been an important problem restricting their practical applications. In this work, we observe that the VTH of polymer OFETs with the widely investigated device structure of a SiO2 bottom-gate dielectric is noticeably shifted by pre-applying a large gate voltage. Such a shift in VTH remains to a large extent, even after modifying the surface of the SiO2 dielectric using a hexamethyldisilazane (HMDS) self-assembled monolayer. This behavior of VTH can be ascribed to the charge trappings at the bulk of the SiO2. In addition, the generality of this observation is further proven by using two other conjugated polymers including p-type PDPP3T and n-type PTzNDI-2FT, and a similar trend is obtained. [ABSTRACT FROM AUTHOR]

Organic single crystals with low defect density are key functional materials for next‐generation electronics. Classical crystallization commonly results in a high density of molecular steps, which are defects that can trap charge carriers and reduce the mobility of organic semiconductors. Herein, a novel nonclassical crystallization mechanism involving nucleation, fusion, and growth is designed. The introduction of the fusion stage changes the crystal growth mode from three‐dimensional island growth to two‐dimensional layer‐by‐layer growth and leads to large‐area two‐dimensional molecular crystals with almost no molecular steps. Therefore, the average mobility is observed to improve from 1.26 to 2.07 cm2 V−1 s−1. The nonclassical crystallization mechanism paves the way for atomically flat single crystals to probe the intrinsic optoelectronic properties of organic semiconductors. [ABSTRACT FROM AUTHOR]

Conjugated polymer (CP)-based organic field-effect transistors (OFETs) have been considered a potential sensor platform for detecting gas molecules because they can amplify sensing signals by controlling the gate voltage. However, these sensors exhibit significantly poorer oxidizing gas sensing performance than their inorganic counterparts. This paper presents a high-performance nitric oxide (NO) OFET sensor consisting of a poly(3-hexylthiophene) (P3HT) film with an ultrathin nanoporous structure. The ultrathin nonporous structure of the P3HT film was created via deposition through the shear-coating-assisted phase separation of polymer blends and selective solvent etching. The ultrathin nonporous structure of the P3HT film enhanced NO gas diffusion, adsorption, and desorption, resulting in the ultrathin nanoporous P3HT-film-based OFET gas sensor exhibiting significantly better sensing performance than pristine P3HT-film-based OFET sensors. Additionally, upon exposure to 10 ppm NO at room temperature, the nanoporous P3HT-film-based OFET gas sensor exhibited significantly better sensing performance (i.e., responsivity ≈ 42%, sensitivity ≈ 4.7% ppm−1, limit of detection ≈ 0.5 ppm, and response/recovery times ≈ 6.6/8.0 min) than the pristine P3HT-film-based OFET sensors. [ABSTRACT FROM AUTHOR]

Solution-processable [1]benzothieno[3,2-b]benzothiophene (BTBT) derivatives with various end-capping groups, 2-(phenylethynyl)benzo[b]benzo[4,5]thieno[2,3-d]thiophene (Compound 1), 2-octyl-7-(5-(phenylethynyl)thiophen-2-yl)benzo[b]benzo[4,5]thieno[2,3-d]thiophene (Compound 2), and triisopropyl((5-(7-octylbenzo[b]benzo[4,5]thieno[2,3-d]thiophen-2-yl)thiophen-2-yl)ethynyl)silane (Compound 3), have been synthesized and characterized as active layers for organic field-effect transistors (OFETs). Thermal, optical, and electrochemical properties of the newly synthesized compounds were characterized using thermogravimetric analysis (TGA), a differential scanning calorimeter (DSC), UV–vis spectroscopy, and cyclic voltammetry (CV). Thin films of each compound were formed using the solution-shearing method and the thin film surface morphology and texture of the corresponding films were characterized using atomic force microscopy (AFM) and θ–2θ X-ray diffraction (XRD). All semiconductors exhibited p-channel characteristics in ambient and Compound 1 showed the highest electrical performance with a carrier mobility of ~0.03 cm2/Vs and current on/off ratio of ~106. [ABSTRACT FROM AUTHOR]

Conjugated polymers, which exhibit electrical and optical properties owing to the presence of conjugated π bonds along the polymer backbone, are semiconducting materials of utmost interest. However, their immiscibility in water imposes restrictions on their usage; they are typically processed using toxic and environmentally harmful organic solvents. To address these issues, research has focused on converting conjugated polymers into nanoparticle dispersions in water or alcohols. This strategy not only avoids toxic solvent usage but also enhances application utility. In this article, to provide a comprehensive understanding of conjugated polymer nanoparticles, we introduce two principal approaches for classifying nanoparticle formation strategies and their corresponding experimental methods: with respect to the particle formation mechanisms and their preparation methods; we will discuss six such methods. Then, we review three different applications of the conjugated polymer nanoparticles in the fields of electronics, energy, and bioimaging, associating their requirements for attaining superior device performance with the characteristics of each method, and accordingly discuss methodological perspectives for each application. [ABSTRACT FROM AUTHOR]

Organic electrochemical transistors (OECTs) using aqueous gate dielectrics have garnered significant interest for bioelectronic applications. However, their viability for long-term use in neuromorphic computing and synaptic devices is limited due to their short-term functionality. In this study, we synthesize two benzodifurandione-based oligo (p -phenylene vinylene) polymers, BDOPV-TCNVT and ClBDOPV-TCNVT, and investigate their electrochemical transistor properties using quasi-solid-state ion gel-gated vertical OECTs (v -OECTs). Compared to BDOPV-TCNVT, the chlorinated ClBDOPV-TCNVT demonstrates lower frontier molecular orbitals and easier electrochemical doping. The higher volumetric capacitance of as-spun ClBDOPV-TCNVT (1.94 F cm−3) compared to as-spun BDOPV-TCNVT films (1.49 F cm−3) is mainly attributed to the easier ion infiltration resulting from its lower crystallinity with mixed chain orientation. The quasi-solid-state v -OECTs based on both polymers (as-spun) exhibit transconductance (g m) of 0.06–0.08 mS. Following thermal treatments, the g m gradually decreases for both polymers due to enhanced edge-on ordering with tight interchain packing, hindering ion penetration. Despite the poor electrochemical doping by quasi-solid-state ion gel gated dielectrics, the enlarged area and decreased channel length in v- OECTs (compared to parallel OECTs) can enhance the g m. Further optimization of v- OECTs requires tailored material designs specifically suited for efficient vertical charge transport together with ion infiltration. [Display omitted] • 1. Two benzodifurandione-based oligo (p -phenylene vinylene) polymers are synthesized. • Quasi-solid-state ion gel-gated n-type vertical OECTs are fabricated. • Structure, electrochemical doping and vertical charge transport correlations are investigated. [ABSTRACT FROM AUTHOR]

Abstract Organic field‐effect transistors (OFETs) are of great significance in next‐generation optoelectronics and have made remarkable advances during the last decade. For the commercialization of OFETs, power consumption is one of the main issues needed to be addressed. To this end, OFETs with low‐voltage operation are constructed, and several strategies have been successively developed, which have attracted intensive attention for researchers to achieve this goal. In this review, we summarized the recent progress of various approaches for realizing low‐voltage OFETs, including adopting high‐k dielectrics, ultra‐thin dielectric, electrolyte dielectric, and interface engineering. Besides, the potential applications of low‐voltage OFETs in organic electronics are introduced. Finally, we give a brief outlook of this area for the future direction.

Abstract Organic single crystals with low defect density are key functional materials for next‐generation electronics. Classical crystallization commonly results in a high density of molecular steps, which are defects that can trap charge carriers and reduce the mobility of organic semiconductors. Herein, a novel nonclassical crystallization mechanism involving nucleation, fusion, and growth is designed. The introduction of the fusion stage changes the crystal growth mode from three‐dimensional island growth to two‐dimensional layer‐by‐layer growth and leads to large‐area two‐dimensional molecular crystals with almost no molecular steps. Therefore, the average mobility is observed to improve from 1.26 to 2.07 cm2 V−1 s−1. The nonclassical crystallization mechanism paves the way for atomically flat single crystals to probe the intrinsic optoelectronic properties of organic semiconductors.

In this paper, four organic materials based on dithieno[3,2‐b : 2',3'‐d]thiophene (DTT) core structure with end‐capping groups (phenyl and thienyl) and linker (acetylenic and olefinic) between DTT‐core and end‐capping groups were synthesized and characterized as solution‐processable organic semiconductors (OSCs) for organic field‐effect transistors (OFETs). Thermal, optical, and electrochemical properties of the corresponding materials were determined. Next, all DTT‐derivatives were coated by solution‐shearing method, and the thin‐film microstructures and morphologies were investigated. To investigate the electrical performance of four newly synthesized DTT‐derivatives, bottom‐gate/top‐contact OFETs were fabricated and characterized in ambient condition. It was found that substitution of acetylenic for olefinic linkers between DTT‐cores and end‐capping groups enhanced device performance. Especially, the resulting OFETs based on the compound containing phenylacetylene exhibited the highest hole mobility of 0.15 cm2/Vs and current on/off ratio of ∼106, consistent with film morphology and texture showing long range interconnected crystalline grains and strong diffraction peaks. [ABSTRACT FROM AUTHOR]

In the pursuit of achieving high-performance and high-throughput organic transistors, this study highlights two critical aspects: designing new soluble acenes and optimizing their solution processing. A fundamental understanding of the crystallization mechanism inherent to these customized soluble acenes, as they undergo a transformation during the evaporation of residual solvent, is deemed essential. Here, the pathway to crafting ideal solution processing conditions is elucidated, meticulously tailored to the molecular structure of soluble acenes when blended with polymers. Employing a comprehensive array of analytical and computational methodologies, this investigation delves directly into the intricate interplay between processing parameters and crystallization mechanisms, firmly rooted in the domains of thermodynamics and kinetics. Notably, a delicate equilibrium where the optimal weight of residual solvent harmoniously aligns is uncovered with the specific attributes of soluble acene molecules, exerting influence over vertical phase separation with the blended polymer and the crystallization process of soluble acenes at the surface. Consequently, transistors showcasing remarkable field-effect mobility exceeding 8 cm 2  V -1  s -1 are successfully developed. These findings provide invaluable guidance for navigating the path toward determining optimal solution processing conditions across a diverse array of soluble acene/polymer blend systems, all achieved through the strategic application of crystal and residual solvent engineering., (© 2024 Wiley‐VCH GmbH.)

The growing demand of disposable electronics raises serious concerns for the corresponding increase in the amount of electronic waste, with severe environmental impact. Organic and flexible electronics have been proposed long ago as a more sustainable and energy-efficient technological platform with respect to established ones. Yet, such technology is leading to a drastic increase of plastic waste if common approaches for flexible substrates are followed. In this scenario, biodegradable solutions can significantly limit the environmental impact, actively contributing to eliminate the waste streams (plastic or electronic) associated with disposal of devices. However, achieving suitably scalable processes to pattern mechanically robust organic electronics onto largely available biodegradable substrates is still an open challenge. In this work, all-organic and highly flexible field-effect transistors, inkjet printed onto the biodegradable and compostable commercial substrate Mater-Bi, are demonstrated. Because of the thermal instability of Mater-Bi, no annealing steps are applied, producing devices with limited carrier mobility, yet showing correct n-type behavior and robustness to bending and crumpling. The degradation behavior of the final system shows unaltered biodegradability level according to ISO 14851. These results represent a promising step toward sustainable flexible and large-area electronics, combining energy and materials efficient processes with largely available biodegradable substrates.

In this study, we investigated the gas-sensing mechanism in bottom-gate organic field-effect transistors (OFETs) using poly(triarylamine) (PTAA). A comparison of different device architectures revealed that the top-contact structure exhibited superior gas-sensing performance in terms of field-effect mobility and sensitivity. The thickness of the active layer played a critical role in enhancing these parameters in the top-contact structure. Moreover, the distance and pathway for charge carriers to reach the active channel were found to significantly influence the gas response. Additionally, the surface treatment of the SiO2 dielectric with hydrophobic self-assembled mono-layers led to further improvement in the performance of the OFETs and gas sensors by effectively passivating the silanol groups. Under optimal conditions, our PTAA-based gas sensors achieved an exceptionally high response (>200%/ppm) towards NO2. These findings highlight the importance of device and interface engineering for optimizing gas-sensing properties in amorphous polymer semiconductors, offering valuable insights for the design of advanced gas sensors.

Organic field‐effect transistor (OFET) memory based on pentacene has attracted a lot of attentions due to its promising prospect of application in flexible electronics, while the high programming/erasing (P/E) gate voltages due to the existence of hole barrier at pentacene/polymer interface leaves great challenges for its commercial applications. A high‐performance pentacene‐based OFET nonvolatile memory (ONVM) with polymer blends is reported here as the charge‐trapping layer containing poly(2‐vinyl naphthalene) (PVN) and poly{[N,N'‐bis(2‐octyldodecyl)naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5'‐(2,2'‐bithiophene)} (N2200). The presence of N2200, an n‐type semiconductor, in blends significantly improves the memory performance of pentacene‐based memory devices based on the static‐electric effect. The electrons in N2200 are aggregated near the pentacene/polymer interface due to the electric attraction from the positively charged defects in pentacene. Furthermore, those electrons reduce the height of hole barrier and produce local easy‐transportation paths for holes between pentacene and PVN, which enables the electret‐based ONVM device with low P/E voltages, fast P/E speeds, large mobility and stable multilevel data‐storage ability in ambient air. [ABSTRACT FROM AUTHOR]

Printed polymer field-effect transistors are promising devices for manufacturing highly sensitive gas and liquid sensors based on them. However, their practical application as sensors imposes special requirements on structured substrates for the deposition of active semiconductor and receptor layers. A simple approach to the production of a structured polymer substrate using exclusively additive methods for manufacturing from it a printed polymer field-effect transistor suitable for the use as a gas/liquid sensor is presented. [ABSTRACT FROM AUTHOR]

The composites of polymers and two-dimensional (2D) materials show promising applications in the area of gas sensing. In this work, we report an efficient ammonia gas (NH3) sensor based on poly(3-hexylthiophene)/ molybdenum disulfide (P3HT/MoS2) nanocomposite. The sensing device has been fabricated in bottom-gate top contact organic field-effect transistor (OFET) assembly using P3HT/MoS2 as active channel material. The changes in the electrical response of OFET has been measured and analyzed for various ammonia gas concentration at room temperature. The sensing device in the form of an OFET structure is preferred due to multi-parameter characteristics to explore gas sensing applications. The active sensing layer has been fabricated via a self-assembled, cost-effective floating film transfer (FTM) technique. An optimized uniform sensing film of thickness 25±3 nm is used to analyze the change in the electrical characteristic of the device in terms of I/O characteristics, mobility, threshold voltage, trapped charge density, etc., for various ammonia concentrations. The OFET with nanofiber morphology of mobility 0.147 cm2/V-s shows the threshold voltage of −3.78 V (in the air) and changes to −10.71 V after 100 ppm ammonia gas exposure. The device has shown a limit of detection (LOD) of 904 ppb and a sensing response of 63.45% at 100 ppm ammonia concentration. The extraction of multi-parameter sensing characteristics of the device has been conducted in a closed chamber with an ambient environment. The fabricated sensor is therefore having potential applications in high-performance ammonia sensing applications. [ABSTRACT FROM AUTHOR]

Abstract Developing high‐quality electret layer is important for the fabrication of high‐performance nonvolatile organic field effect transistor memory devices (OFET‐NVMs). In this work, three representative aromatic diimide frameworks are employed for comparative studies as n‐type doping materials for the electret layers in OFET‐NVMs, which are naphthalene diimide (NDI), perylene diimide (PDI), and pyrene diimide (PyDI). When blended with polystyrene (PS) to prepare the electret layers, all the memory devices containing aromatic diimide dopants exhibited significantly improved performances compared with the undoped counterparts, indicating that low‐lying LUMO energy levels of these dopants are beneficial for charge injection. All the devices with n‐type dopants exhibited long retention times (more than 104 s) and good switching reliability in more than 400 continuous write‐read‐erase‐read cycles. Among them, the PyDI‐based memory device exhibited superior performance compared with other aromatic diimides, which achieved a memory window of 34.0 V, a trapping charge density of 1.98 × 1012 cm−2 along with an on/off ratio higher than 104. This work indicates that PyDI framework could be a new platform for the future design of n‐type dopant for high‐performance nonvolatile organic field‐effect transistor memory devices.

Low voltage and high frequency organic field‐effect transistors (OFETs) show great potential in the field of wearable devices. To clarify the high frequency operation mechanism of OFETs, this work presents a frequency characterization model and verifies it through simulations in Atlas. The current gain cut‐off frequency model derivation for the OFETs was carried out in the subthreshold region, including conventional physical factors such as effective mobility, channel length, channel width, contact length, and gate dielectric capacitance. Besides these, the trapgap density at the channel was initially considered as an important factor affecting the cut‐off frequency of OFETs. Together with contact lengths, their influence on the current gain cut‐off frequency was verified with simulations in Atlas. [ABSTRACT FROM AUTHOR]

Diketopyrrolopyrrole (DPP), due to its good planarity, π-conjugate structure, thermal stability, and structural modifiability, has received much attention from the scientific community as an excellent semiconductor material for its applications in the field of optoelectronics, such as organic solar cells, organic photovoltaics, and organic field effect transistors. In this study, a new small molecule, pyrrolopyrrole aza-BODIPY (PPAB), based on the thiophene-substituted DPP structure was developed using the Schiff-base formation reaction of DPP and heteroaromatic amines. Absorption spectroscopy, electrochemistry, X-ray diffraction, molecular theoretical simulation calculation were performed, and organic field-effect transistor properties based on PPAB were investigated. It was found that PPAB exhibits a broad absorption range in the visible and near-infrared regions, which is attributed to its long-range conjugate structure. In addition, it is worth noting that PPAB has multiple F atoms resulting in the low LUMO level, which is conducive to the injection and transportation of charge carriers between the semiconductor layer and the electrode. Meanwhile, its hole carrier mobility is up to 1.3 × 10−3 cm2 V−1 s−1 due to its large conjugate structure, good intramolecular charge transfer effect, and high degree of coplanarity. In this study, a new chromophore with electron-deficient ability for designing high-performance semiconductors was successfully synthesized.

A novel alternating donor–acceptor polymer PQ1 is designed and synthesized by palladium-catalyzed Stille coupling between quinoxaline as an electron-deficient unit and indacenodithiophene (IDT) as electron-rich groups. Polymer PQ1 presents not only a strong intramolecular charge transfer effect, which is beneficial for the charge transport within single molecules but also a narrow electrochemical band gap and a high highest occupied molecular orbital (HOMO) energy level. In addition, the optical absorption study indicates that the PQ1 film exhibits good aggregation, which is an advantage for the charge transport between neighboring molecules. As a consequence, PQ1 presents p-type semiconductor properties with a high hole mobility of up to 0.12 cm2 V−1 s−1. This study reveals the great potential of quinoxaline-type chromophores in constructing novel organic semiconductors.

Electrospun nanofibers have become the most promising building blocks for future high-performance electronic devices because of the advantages of larger specific surface area, higher porosity, more flexibility, and stronger mechanical strength over conventional film-based materials. Moreover, along with the properties of ease of fabrication and cost-effectiveness, a broad range of applications based on nanomaterials by electrospinning have sprung up. In this review, we aim to summarize basic principles, influence factors, and advanced methods of electrospinning to produce hundreds of nanofibers with different structures and arrangements. In addition, electrospun nanofiber based electronics composed of both two-terminal and three-terminal devices and their practical applications are discussed in the fields of sensing, storage, and computing, which give rise to the further integration to realize a comprehensive and brain-like system. Last but not least, the emulation of biological synapses through artificial synaptic transistors and additionally optoelectronics in recent years are included as an important step toward the construction of large-scale, multifunctional systems. [ABSTRACT FROM AUTHOR]

In this work, a low temperature (+, K+, and H+ ions.

Diketopyrrolopyrrole (DPP)-based polymeric semiconductors have recently attracted widespread attention and, due to their high field-effect mobility values, been studied for the field of organic field-effect transistors (OFETs). DPP-based polymers are composed of the electron-deficient DPP and two flanking aromatic units, and have excellent electronic properties due to their main chain planarity and strong donor-acceptor intermolecular interactions. In the current review, we summarize the pathways used to synthesize DPP-based polymers, the effects of engineering the main chains and side chains of these polymers on the p-type/n-type/ambipolar semiconducting performances of OFETs made using these polymers, and applications of these OFETs as chemical sensors. [ABSTRACT FROM AUTHOR]

Large elongated single crystals (2.91 mm × 97 μm) of 1,6-dibromopyrene were successfully obtained from solution using the slow evaporation method. Their carrier mobility was obtained via current–voltage characteristics of bottom-gate bottom-contact-type field-effect transistors. In these devices, the longitudinal direction of each crystal was parallel or perpendicular to the conductive channel. The highest mobility was 6.0 × 10−4 cm2 V−1 s−1 and 2.2 × 10−3 cm2 V−1 s−1 in the linear and saturation region, respectively, when the electric current flowed across the crystal's longitudinal direction. The emission strength ratio and mobility ratio between the two longitudinal directions (parallel and perpendicular to the conductive channel, respectively) were 3.1 and 2.2. X-ray diffraction measurements suggested that both the emission strength and mobility are larger in the transverse intermolecular contact direction than in the stacking direction. The mobilities in the linear region were tentatively corrected by subtracting the contributions of charge injection barriers and were estimated to be 2.1–2.9 times larger than the uncorrected ones. The results of this study suggest that bromine substitution is one of the effective methods to modify the optical properties and improve the solution processability of organic semiconductor materials while maintaining the carrier mobility. [ABSTRACT FROM AUTHOR]