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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]

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]

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]

Solution‐processing approaches are widely used for controlling the aggregation structure of organic semiconductors because they are fast, efficient, and have strong practicability. Effective regulation of the aggregation structure of molecules to achieve highly ordered molecular stacking is key to realizing effective carrier transport and high‐performance devices. Numerous studies have achieved highly aligned organic semiconductors using different solution‐processing approaches. This article provides a detailed review of the prevalent solution‐processing technologies and emerging methods developed over the past few years for the alignment of organic semiconducting materials. These technologies and methods are classified according to the processing principle. This review focuses on the principles of different experimental techniques, improvements upon the conventional methods, and state‐of‐the‐art performance of resulting devices. In addition, a brief discussion of the characteristics and development prospects of various methods is presented. [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]

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]

Abstract: We have developed a solution process to the synthesis of self-supported Bi2S3 patterns with one-dimensional (1D) Bi2S3 nanostructures. It was found that the surfactant plays a key role in determining the shape of the products. The as-prepared products were characterized by means of powder X-ray diffraction (XRD) and field emission scanning electronic microscopy (FE-SEM). In comparison with the original traditional apparatus, the present route is safe, simple, reproducible, and environmentally benign, and yields nanocrystals with well-controlled size and shape. [Copyright &y& Elsevier]

Ambipolar field-effect transistors based on polymer semiconductors facilitate the convenient fabrication of low-power complementary organic circuits. However, the species of ambipolar polymer semiconductors are limited; the design and synthesis strategies are scarce. This work demonstrated that bisthiophene-fused diketopyrrolopyrrole (DPPFu) was a wonderful building unit for ambipolar polymer semiconductors. Ambipolar polymer semiconductors could be obtained by copolymerizing DPPFu with both electron-deficient comonomers and electron-rich comonomers. P(DPPFu-T), P(DPPFu-TT) and P(DPPFu-BT) were synthesized by copolymerizing DPPFu with thiophene, thienothiophene and benzothiadiazole, respectively. The structural variation of comonomers allowed for a systematic study on the relationship between comonomer structure, frontier orbital energy level, orbital delocalization index, molecular packing, film morphology and the corresponding charge transport properties. Thienothiophene endowed P(DPPFu-TT) with maximum orientation of edge-on packing. The considerable delocalization extent of the lowest unoccupied molecular orbitals (LUMOs) for P(DPPFu-T) and P(DPPFu-TT) resulted in pronounced electron transport property. P(DPPFu-TT) displayed the best charge transport property with hole mobility up to about 0.1 cm2V−1s−1 and electron mobility of 7.5 × 10−2 cm2V−1s−1. P(DPPFu-BT) showed ideally balanced charge carrier mobilities for both holes and electrons of 1.6 × 10−2 cm2V−1s−1 and 1.7 × 10−2 cm2V−1s−1, respectively. Ion/Ioff ratios of all the ambipolar polymers were above 103. The ambipolarity of polymer semiconductors was related to not only push-pull electronic characteristics of comonomers, but also the planarity of polymer backbones and delocalization extent of frontier orbitals. Overall, this study provides valuable insights into the design and synthesis of ambipolar polymer semiconductors, which is crucial for the advancement of low-power complementary organic circuits. All the polymer semiconductors exhibited prominent ambipolar charge transport property. P(DPPFu-TT) displayed the best charge transport property and P(DPPFu-BT) showed ideally balanced charge carrier mobilities for both holes and electrons. Relationships between comonomer structure, frontier orbital energy level, orbital delocalization index, molecular packing, film morphology and the corresponding charge transport properties were investigated systematically. [Display omitted] • A series of ambipolar polymer semiconductors based on DPPFu were designed and successfully synthesized. • DFT calculations were employed to predict the physical characteristics of the ambipolar polymer semiconductors • Relationships between molecular packing, film morphology and charge transport properties were investigated systematically. • The hole and electron mobility of P(DPPFu-TT) were found to reach approximately 0.1 and 7.5×10-2 cm2V–1s–1, respectively. [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]

Benzopyrazinoisoindigo, a pigment reported 40 years ago, should be a good candidate for n-type semiconductors if the reported structure is correct. Reinvestigation of this molecule revealed that it is actually (4 H,4′ H)-benzopyrazinoisoindigo, which could be considered as the reduced form of benzopyrazinoisoindigo, and hence, it is a good candidate for p-type semiconductors. The route toward the synthesis of this molecule was optimized, and a mechanism was accordingly proposed. A field-effect transistor based on this material showed a hole mobility up to 2.5 × 10-2 cm2 V-1 s-1. [ABSTRACT FROM AUTHOR]

An oligothiophene‐based molecule (BDT‐3T‐CA) using a molecular engineering approach is applied to solution‐processed layer‐by‐layer solar cells. The solar cells based on BDT‐3T‐CA/PC61BM (a fullerene derivative) exhibit power conversion efficiency (PCE) values as high as 4.16% and fill factor (FF) values up to 0.75. The FF of 0.75 is the highest value reported for solution processed small molecule solar cells. [ABSTRACT FROM AUTHOR]

Two structural isomers of six-fused-ring sulfur-containing molecules were synthesized as active materials for p-type organic field-effect transistors, and their optical and electrochemical properties were characterized. Field-effect transistors based on these compounds were fabricated to investigate the relationships between structures and semiconductor properties. [ABSTRACT FROM AUTHOR]

Single-walled carbon nanotubes (SWNTs) possess unique electronic properties that make them very promising materials for use in both nano-electronics and thin film devices. However, SWNTs are always produced as a mixture of metallic and semiconducting nanotubes, which is a major roadblock to their widespread application. This tutorial reviewprovides a brief summary of ways of separating single-walled carbon nanotubes into metallic and semiconducting fractions. Various methods including selective growth, selective removal, selective adsorption and band structure modulation—all of which aim to produce pure SWNTs with well-defined electronic properties—are systematically discussed. The main problems in this field, the outlook for separation techniques and some views of future developments are presented. [ABSTRACT FROM AUTHOR]

The authors reported organic phototransistors (PTs) with octadecyltrichlorosilane treated SiO2/Si substrate based on anthra[2,3-b]benzo[d]thiophene. The organic PTs show a high mobility of 0.4 cm2 V-1 s-1, a maximum photoresponsivity of about 1000 A/W, and photocurrent/dark-current ratio of around 800 under white light irradiation with 30 μW/cm2. The data are comparable with those of PTs based on amorphous silicon. Meanwhile, it is interesting to see that the devices show a high air-stable property and high photosensitivity via electric-field enhanced process. All these phenomena were attributed to the intrinsic optic-electronic property of the organic semiconductor and optic-electric field effect. [ABSTRACT FROM AUTHOR]

The aim of this study is to establish the structure-properties relationship of tetrathiafulvalene (TTF). After this study (1) TTF crystals with α and β phases were controllably obtained by the cast method with careful selection of the solvents, and (2) organic field-effect transistors (OFETs) of α and β phases both exhibited field-effect performance, and the performance of α phase was much better than that of β phase. The highest mobility of α phase reached 1.2 cm2 V-1 s-1, while β phase showed the maximum mobility only about 0.23 cm2 V-1 s-1, indicating the strong performance dependence of OFETs performance on the crystal phases. [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 reinvestigation of the title pigment reveals that it is actually alkylated (4H,4′H)-benzopyrazinoisoindigo (Ia-c), which could be considered as the reduced form of benzopyrazinoisoindigo, and hence, it is a good candidate for p-type semiconductors. [ABSTRACT FROM AUTHOR]