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Developing new polymeric semiconductors with excellent device performance is essential for organic electronics. Herein, we synthesized two new thiazoloisoindigo (TzII)-based polymers, namely, P(TzII-dTh-dTh) and P(TzII-dTh-dTz), by copolymerizing thiophene-flanked TzII with bithiophene and bithiazole, respectively. Owing to the more electron-deficient nature of bithiazole than bithiophene, P(TzII-dTh-dTz) possesses deeper LUMO/HOMO levels of −3.45/−5.47 eV than P(TzII-dTh-dTh) (−3.34/−5.32 eV). The organic field-effect transistor (OFET) devices based on P(TzII-dTh-dTh) exhibited p-type behaviors with an average hole mobility value as high as 1.43 cm2·V−1·s−1, while P(TzII-dTh-dTz) showed typical ambipolar characteristics with average hole and electron mobilities of 0.38 and 0.56 cm2·V−1·s−1. In addition, we compared the performances of both polymers with other TzII-based polymers reported in our previous work, and showed that the charge carrier polarity can be manipulated by adjusting the number of the thiophene units between the acceptor unit. As the increase of the number of thiophene rings, charge carrier polarity shifts from electron-dominated ambipolar transport to hole-dominated ambipolar transport and then to unipolar hole transport in OFETs, which provides an effective molecular design strategy for further optimization of polymer OFET performance. [ABSTRACT FROM AUTHOR]

Donor-acceptor (D-A) conjugated polymers comprising electron-deficient aromatic dicarboximide units represent an important type of organic semiconductors, especially for electron transporting properties. Pyrene-1,5,6,10-tetracarboxyl diimide (PyDI), a new PAH dicarboximide molecule recently reported by us, provides a fine balance between the electron-stabilizing ability and π-stacking tendency, as compared to the naphthalenediimide (NDI) and perylenediimide (PDI) analogues. In this study, using thienylene-vinylene-thienylene (TVT) and biselenophene (BS) as the electron donating comonomer, along with PyDI as the acceptor moiety, we develop two new D-A type conjugated polymers, which exhibit impressive electron-transporting performance. Specifically, in the solution-processed OFET devices, electron mobility of 0.18 and 0.20 cm2·V−1·s−1 are achieved with these polymers, respectively. Such findings further prove the optimal potential of PyDI for application as an electron-acceptor building block in the development of polymeric n-type semiconductors among all various high-performance functional D-A polymers. [ABSTRACT FROM AUTHOR]

Despite the remarkable synthetic accomplishments in creating diverse polycyclic aromatic hydrocarbons with B−N bonds (BN‐PAHs), their optoelectronic applications have been less exploited. Herein, we report the achievement of high‐mobility organic semiconductors based on existing BN‐PAHs through a "periphery engineering" strategy. Tetraphenyl‐ and diphenyl‐substituted BN‐anthracenes (TPBNA and DPBNA, respectively) are designed and synthesized. DPBNA exhibits the highest hole mobility of 1.3 cm2 V−1 s−1 in organic field‐effect transistors, significantly outperforming TPBNA and all the reported BN‐PAHs. Remarkably, this is the first BN‐PAH with mobility over 1 cm2 V−1 s−1, which is a benchmark value for practical applications as compared with amorphous silicon. Furthermore, high‐performance phototransistors based on DPBNA are also demonstrated, implying the high potential of BN‐PAHs for optoelectronic applications when the "periphery engineering" strategy is implemented. [ABSTRACT FROM AUTHOR]

Molecular doping plays an important role in the modification of carrier density of organic semiconductors thus enhancing their optoelectronic performance. However, efficient n‐doping remains challenging, especially owing to the lack of strongly reducing and air‐stable n‐dopants. Herein, an N‐heterocyclic carbene (NHC) precursor, DMImC, is developed as a thermally activated n‐dopant with the excellent stability in air. Its thermolysis in situ regenerates free NHC and subsequently dopes typical organic semiconductors. In sequentially doped FBDPPV films, DMImC does not disturb the π–π packing of the polymer and achieves good miscibility with the polymer. As a result, a high electrical conductivity of up to 8.4 S cm−1 is obtained. Additionally, the thermally activated doping and the excellent air stability permit DMImC to be noninteractively co‐processed with polymers in air. Our results reveal that DMImC can be served as an efficient n‐dopant suitable for various organic semiconductors. [ABSTRACT FROM AUTHOR]

A new electron-deficient unit with a fused 5-membered heterocyclic ring was developed by replacing a cyclopenta-1,3-diene from electron-rich donor indacenodithiophene (IDT) with a cyclohepta-4,6-diene-1,3-diimde unit. The imide bridge endows dithienylbenzenebisimide (BBI) with a fixed planar configuration and low energy levels for both the highest occupied molecular orbital (HOMO; −6.24 eV) and the lowest unoccupied molecular orbit (LUMO; −2.57 eV). Organic field-effect transistors (OFETs) based on BBI polymers exhibit electron mobility up to 0.34 cm2 V−1 s−1, which indicates that the BBI is a promising n-type building block for optoelectronics. [ABSTRACT FROM AUTHOR]

A thiophene-fused polycyclic azaborine skeleton was employed into conjugated polymers for organic field-effect transistors for the first time. Two polythiophene-type polymers were developed, which exhibited low HOMO levels and strong intermolecular interactions, leading to a hole mobility of up to 0.38 cm2 V−1 s−1. [ABSTRACT FROM AUTHOR]

Recently, many efforts have been devoted to developing novel polycyclic aromatics due to their unique optical and electronic properties and broad applications, such as in organic field-effect transistors, organic photovoltaics, and organic light-emitting diodes. Among various π-conjugated molecules, many truxene derivatives have interesting characteristics such as C3-symmetry, strong blue emission, and a planar rigid structure. Moreover, compared with many other π-conjugated aromatics, the synthesis and modification of truxene are particularly facile and diverse. In this account, we summarize investigations into truxene derivatives from synthesis and physical properties to applications in organic electronics. [ABSTRACT FROM AUTHOR]

Inthe past couple of years, remarkable progress has been madein solution-processable organic semiconducting materials for optoelectronics.The development of novel π-conjugated backbones has always beenthe central issue in this field. In contrast, flexible side chainsare less developed and usually used only as solubilizing groups. Inthis Perspective, we highlight the effects of the flexible chainsin organic semiconductors, including the influences of length, odd–eveneffect, substitution position, terminal groups, branching position,and chirality of alkyl chains, as well as some significant featuresof oligo(ethylene glycol) and fluoroalkyl chains. Although the rolesof flexible chains in organic semiconducting materials are complexand differ when corresponding conjugated skeleton changes, in thisPerspective, we emphasize the synergy of conjugated backbones andflexible side chains, which might significantly facilitate the understandingof the roles of flexible chains in structure–property relationshipand promote the development of high-performance organic semiconductors. [ABSTRACT FROM AUTHOR]

Abstract: The performance of the single organic submicrometer ribbon based photodetector has been improved by one order of magnitude by combining a better crystalline structure with proper surface engineering, such as coating a dielectric layer PMMA or PS between the substrate and the organic semiconductor. The photoconductivity gain is as much as 1.3×104, the responsivity is about 4372AW−1 at the field of about 2×106 Vm−1, and the highest on/off ratio reaches 104. The extremely high gain is attributed to the high mobility and the long photo carrier’s lifetime induced by the dielectric layer. [Copyright &y& Elsevier]

A new family of sulfur-heteroarenes with a chrysene core was developed. Top-contact FET devices were fabricated with hole mobility up to 0.4 cm2V−1s−1. The results suggest that in addition to the much explored linear acenes, molecules with a nonlinearly fused core could also be used as active material in high-performance OFET. [ABSTRACT FROM AUTHOR]