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This article discusses the recent progress in the development of high-mobility polymer semiconductors with various functionalities. These semiconductors have advantages such as easy solution processing, large-area manufacturing, mechanical strength, and flexibility. The article focuses on the integration of high mobility with stretchability, strong luminescence, photolithography patterning, and efficient thermoelectric conversion. The challenges and future directions in this field are also discussed. The research is supported by various funding sources. [Extracted from the article]

Intrinsically stretchable light‐emitting polymer semiconductors are essential building blocks for bioelectronics and display textiles. Stretchability is challenging for rigid conjugated polymers unless sacrificing charge mobility by introducing amorphous domains. High‐performance light‐emitting properties designed with twisted angle are undesirable for conductive materials. Hence, the concurrent strategies hardly satisfy the balance of stretchability, light‐emitting and mobility. Herein, a morphology engineering is proposed by controlling micro‐crystalline and limiting aggregation, that four intrinsically stretchable emissive polymers with good charge mobility based on indacenodithiophene (IDT) are obtained. Polymers reveal good emission properties with high photoluminescence quantum yields (PLQY) of about 20%, while stretchable modulus and charge mobility are tunable by backbone and weight. Specifically emphasizing, IDT‐2T‐H retains high performance of charge mobility and PLQY even at 100% strain. Therefore, organic light emitting diodes are fabricated based on it and showing the luminance of 176.2 cd cm−2, which verifies the potential of technique to reconcile integration of stretchability, light‐emitting, and mobility. This is the first attempt to integrate balanced mechanical, optical, and electrical properties through micro‐crystalline aggregation‐limited morphology in one polymer, offering a feasible approach to advanced integrated circuit and multi‐functional electronics in the future. [ABSTRACT FROM AUTHOR]

The development of polymer semiconductors with strong luminescence and high mobility has always been challenging, and achieving both properties together is considered paradoxical according to molecular design principles. Studies on novel molecular species with unique optoelectrical characteristics are limited. Herein, a novel fully rigid coplanar thiophene‐pyridal[1,2,3]triazole‐thiophene (T‐PT‐T) class structure with considerable intramolecular noncovalent interactions is proposed. To balance luminescence and carrier transport properties, a series of non‐conventional regioregular conjugated polymers (PPTs) with suitable energy gaps (Egs ≈ 1.8 eV) are developed, which exhibit near‐infrared (NIR, 700–1000 nm) light emission and high mobility. One of the synthesized polymers, PPT‐2, exhibits an excellent photoluminescence quantum yield (PLQY) of 9% in the solid‐state and a high mobility reaching 0.35 cm2 V−1 s−1, indicating superior performance compared to other NIR light‐emitting polymer semiconductors. The authors believe that the class structure of fully rigid coplanar "T‐PT‐T" could be harnessed to develop high‐mobility NIR light‐emitting polymer semiconductors. [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]

Abstract: Ammonia/amine gas sensors have received increasing attention in recent years, due to their applications in monitoring of meat and seafood spoilage and air pollution as well as diagnosis of chronic diseases. Herein, a new conjugated polymer PTTEH is developed, which is composed of thieno[3,4‐b]thiophene units, with very low bandgap. The low bandgap and the existence of radical state endow the polymer thin film with good electrical conductivity. As a result, PTTEH is successfully utilized for construction of a field‐effect transistor (FET) sensor for ammonia and amines at low driving voltages, which are advantageous for practical applications. Moreover, this FET sensor shows good selectivity and high sensitivity (down to 10 ppb) toward ammonia and amines. Accordingly, the real‐time monitoring of meat spoilage is achieved with this FET sensor. These studies will open a new venue to fabricate sensitive, portable, and small size sensors for real‐time monitoring of chemical vapors. [ABSTRACT FROM AUTHOR]

ABSTRACT Reversible addition-fragmentation chain transfer (RAFT) emulsion polymerization is becoming an important technique to synthesize the latex of block copolymers. A previous study showed that in the synthesis of polystyrene- b-poly(butyl acrylate)- b-polystyrene triblock copolymer via RAFT emulsion polymerization using amphiphilic oligo(acrylic acid-styrene) macroRAFT as surfactant and mediator, the molecular weight distribution could be much broadened to PDI higher than 2. In this study, an in-depth investigation was performed to decrease PDI. It was found that long-chain branches could be formed in the synthesis of triblock block copolymer, leading to the appearance of a higher molecular weight shoulder in the GPC curve of the final product. The lower neutralization degree of acrylic acid (AA) units on the macroRAFT and shorter AA chains would help to suppress the formation the long-chain branches, leading to PDI around 1.5. It is evidenced that the successful suppression is due to the promotion of radical entry as a result of decreased interfacial transport impedance. It is also evidenced that the presence of styrene during the polymerization of butyl acrylate could promote the formation of long chain branches. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1464-1473 [ABSTRACT FROM AUTHOR]

ABSTRACT Two furan-flanked polymers poly{3,6-difuran-2-yl-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thienylenevinylene} (PDVFs), with a highly π-extended diketopyrrolopyrrole backbone, are developed for solution-processed high-performance polymer field-effect transistors (FETs). Atomic force microscopy and grazing incidence X-ray scattering analyses indicate that PDVF-8 and PDVF-10 films exhibit a similar nodular morphology with the ultrasmall lamellar distances of 16.84 and 18.98 Å, respectively. When compared with the reported polymers with the same alkyl substitutes, this is the smallest d-spacing value observed to date. This closed lamellar crystallinity facilitates charge carrier transport. Therefore, polymer thin-film transistors fabricated from as-spun PDVF-8 films exhibit a high hole mobility exceeding 1.0 cm2 V−1 s−1 with a current on/off ratio above 106. After annealing treatment at 100 °C in air, the highest hole mobility of PDVF-8-based FETs was significantly improved to 1.90 cm2 V−1 s−1, which is among the highest values of the reported FET devices fabricated from polymer thin films based on this mild annealing temperature. In contrast, long alkyl-substituted PDVF-10 exhibited a relatively low hole mobility of 1.65 cm2 V−1 s−1 mainly resulting from low molecular weight. This work demonstrated that PDVFs would be promising semiconductors for developing cost-effective and large-scale production of flexible organic electronics. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1970-1977 [ABSTRACT FROM AUTHOR]

Solution-processable polymers consisting of perylene diimide (PDI) acceptor moieties alternating with dithienothiophene (DTT), N-dodecyl-dithienopyrrole (DTP), or oligomers of these donor groups have been synthesized. We have, in addition to varying the donor, varied the N,N′ substituents of the PDIs. The thermal, optical, electrochemical, and charge-transport properties of the polymers have been investigated. The polymers show broad absorption extending from 300 to 1000 nm with optical band gaps as low as 1.2 eV; the band gap decreases with increasing the conjugation length of donor block, or by replacement of DTT by DTP. The electron affinities of the polymers, estimated from electrochemical data, range from −3.87 to −4.01 eV and are slightly affected by the specific choice of donor moiety, while the estimated ionization potentials (−5.31 to −5.92 eV) are more sensitive to the choice of donor. Bottom-gate top-contact organic field-effect transistors based on the polymers generally exhibit n-channel behavior with electron mobilities as high as 1.7 × 10-2 cm2/V/s and on/off ratios as high as 106; one PDI-DTP polymer is an ambipolar transport material with electron mobility of 4 × 10-4 cm2/V/s and hole mobility of 4 × 10-5 cm2/V/s in air. There is considerable variation in the charge transport properties of the polymers with the chemical structures. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 [ABSTRACT FROM AUTHOR]

For donor–acceptor conjugated polymers, it is an effective strategy to improve their electron mobilities by introducing electron‐withdrawing groups (EWGs, such as F, Cl, or CF3) into the polymer backbone. However, the introduction of different EWGs always requires a different synthetic approach, leading to additional arduous work. Here, an effective two‐step method is developed to obtain EWG substituted bay‐annulated indigo (BAI) units. This method is effective to introduce various EWGs (F, Cl, or CF3) into BAI at different substituted positions. Based on this method, EWG substituted BAI acceptors, including 2FBAI, 2ClBAI, and 2CF3BAI, are reported for the first time. Furthermore, four polymers of PBAI‐V, P2FBAI‐V, P2ClBAI‐V, and P4OBAI‐V are developed. All the polymers show ambipolar transport properties. Particularly, P2ClBAI‐V exhibits remarkable hole and electron mobilities of 4.04 and 1.46 cm2 V−1 s−1, respectively. These mobilities are among the highest values for BAI‐based polymers. Here, an effective two‐step method is developed to obtain an electron‐withdrawing group (EWG) substituted bay‐annulated indigo (BAI) units. Four polymers, PBAI‐V, P2FBAI‐V, P2ClBAI‐V, and P4OBAI‐V, are developed by this method. Particularly, P2ClBAI‐V exhibits remarkable hole and electron mobilities of 4.04 and 1.46 cm2 V−1 s−1, respectively. These mobilities are among the highest values for BAI‐based polymers. [ABSTRACT FROM AUTHOR]

A new diketopyrrolopyrrole-based π-conjugated copolymer(PDPP5T)with high molecular weight has been synthesized by Stille couplingpolymerization of 3,6-bis(5-bromothiophen-2-yl)-2,5-bis(2-octyldodecyl)pyrrolo-[3,4-c]pyrrole-1,4(2H,5H)-dionewith α,α′-bis(trimethylstannyl)-terthiophene. Itshole mobility without thermal annealing reaches 1.08 cm2V–1s–1, and a higher hole mobilityof 3.46 cm2V–1s–1is obtained annealed at 200 °C directly in an air atmosphere.This indicates that introducing a longer β-unsubstituted quinquethiophene(5T) unit into the main-chain of DPP-oligothiophene copolymer producesmuch pronounced p-type behavior and also reduces the steric hindranceof the bulk side-chain groups, which is favorable to enhance the molecularordering capability at low temperatures and improve the organic thin-filmtransistors (OTFT) performances. This work demonstrates that PDPP5Tis a promising material that can be applied to the cost-effectiveand large-scale production of OTFTs. [ABSTRACT FROM AUTHOR]