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Polymer semiconductors are promising candidates for wearable and skin-like X-ray detectors due to their scalable manufacturing, adjustable molecular structures and intrinsic flexibility. Herein, we fabricated an intrinsically stretchable n-type polymer semiconductor through spatial nanoconfinement effect for ultrasensitive X-ray detectors. The design of high-orientation nanofiber structures and dense interpenetrating polymer networks enhanced the electron-transporting efficiency and stability of the polymer semiconductors. The resultant polymer semiconductors exhibited an ultrahigh sensitivity of 1.52 × 10 4 μC Gy air -1 cm -2 , an ultralow detection limit of 37.7 nGy air s -1 (comparable to the record-low value of perovskite single crystals), and polymer film X-ray imaging was achieved at a low dose rate of 3.65 μGy air s -1 (about 1/12 dose rate of the commercial medical chest X-ray diagnosis). Meanwhile, the hybrid semiconductor films could sustain 100% biaxial stretching strain with minimal degeneracy in photoelectrical performances. These results provide insights into future high-performance, low-cost e-skin photoelectronic detectors and imaging., (© 2022. The Author(s).)

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]

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]

Highly aligned aggregation state structures have great significance for effective charge‐carrier transport in organic semiconductors. Several methods have been developed to provide organic semiconducting molecules with highly oriented aggregation state structure; among these, using a water surface to form organic semiconductor films is a widely implemented strategy, wherein solutions are spread on the surface of water. However, common techniques of film formation on water surfaces generally result in a nonuniform orientation of the film owing to the isotropic spread process of droplets on the water surface. In this study, a spatially confined air/water interfacial assembly method is proposed to obtain uniformly aligned monolayer and multilayer poly(diketopyrrolopyrrole‐thieno[3,2‐b]thiophene) thin films with controlled thickness. The structural and morphological characterizations obtained using atomic force microscopy, high‐resolution transmission electron microscopy, and grazing incidence wide‐angle X‐ray scattering indicates the crystalline structure of the thin films and high alignment of the molecular chains. The maximum mobility of the thin films reaches up to 2.06 and 0.5 cm2 V−1 s−1 in the parallel and perpendicular direction, respectively, indicating apparent anisotropic electrical properties. Furthermore, an inverter based on these thin films exhibits a voltage gain of up to 70, demonstrating the potential of applying the proposed technique to logic circuits. [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]

Large area and highly aligned polymer semiconductor sub-microwires were fabricated using the coaxial focused electrohydrodynamic jet printing technology. As indicated by the results, the sub-microwire arrays have smooth morphology, well reproducibility and controllable with a width of ~110 nm. Analysis shows that the molecular chains inside the sub-microwires mainly exhibited edge-on arrangement and the π-stacking direction (010) of the majority of crystals is parallel to the long axis of the sub-microwires. Sub-microwires based organic field effect transistors showed high mobility with an average of 1.9 cm2 V−1 s−1, approximately 5 times higher than that of thin film based organic field effect transistors. In addition, the number of sub-microwires can be conveniently controlled by the printing technique, which can subsequently concisely control the performance of organic field effect transistors. This work demonstrates that sub-microwires fabricated by the coaxial focused electrohydrodynamic jet printing technology create an alternative path for the applications of high-performance organic flexible device. Here, the authors fabricate large area and highly aligned polymer semiconductor sub-microwires arrays via coaxial focused electrohydrodynamic jet printing technology, achieving high on/off ratio and average mobility that is 5x higher than that of thin film based organic field effect transistors. [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]

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]