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  1. Abstract Next-generation wearable electronics require enhanced mechanical robustness and device complexity. Besides previously reported softness and stretchability, desired merits for practical use include elasticity, solvent resistance, facile patternability and high charge carrier mobility. Here, we show a molecular design concept that simultaneously achieves all these targeted properties in both polymeric semiconductors and dielectrics, without compromising electrical performance. This is enabled by covalently-embedded in-situ rubber matrix (iRUM) formation through good mixing of iRUM precursors with polymer electronic materials, and finely-controlled composite film morphology built on azide crosslinking chemistry which leverages different reactivities with C–H and C=C bonds. The high covalent crosslinking density results in both superior elasticity and solvent resistance. When applied in stretchable transistors, the iRUM-semiconductor film retained its mobility after stretching to 100% strain, and exhibited record-high mobility retention of 1 cm 2 V −1 s −1 after 1000 stretching-releasing cycles at 50% strain. The cycling life was stably extended to 5000 cycles, five times longer than all reported semiconductors. Furthermore, we fabricated elastic transistors via consecutively photo-patterning of the dielectric and semiconducting layers, demonstrating the potential of solution-processed multilayer device manufacturing. The iRUM represents a molecule-level design approach towards robust skin-inspired electronics. 
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  2. null (Ed.)
    Organic electronics technologies have attracted considerable interest over the last few decades and have become promising alternatives to conventional, inorganic platforms for specific applications. To fully exploit the touted potential of plastic electronics, however, other prerequisites than only electronic functions need to be fulfiled, including good mechanical stability, ease of processing and high device reliability. A possible method to overcome these issues is the employment of insulating:semiconducting polymer blends, which have been demonstrated to display favourable rheological and mechanical properties, generally provided by the insulating component, without negatively affecting the optoelectronic performance of the semiconductor. Here, we demonstrate that binary blends comprising the semicrystalline high-density polyethylene (HDPE) in combination with hole- and electron-transporting organic semiconductors allow fabrication of p-type and n-type thin-film transistors of notably improved device stability and, in some scenarios, improved device performance. We observe, for example, considerably lower subthreshold slopes and drastically reduced bias-stress effects in devices fabricated with a hole-transporting diketopyrrolopyrrole polymer derivative when blended with HDPE and significantly enhanced charge-carrier mobilities and shelf life in case of transistors made with blends between HDPE and the electron-transporting poly{[ N , N ′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)2,6-diyl]- alt -5,5′-(2,2′-bithiophene)}, i.e. P(NDI2OD-T2), also known as N2200, compared to the neat material, highlighting the broad, versatile benefits blending semiconducting species with a semicrystalline commodity polymer can have. 
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  3. Abstract

    Organic photovoltaic power conversion efficiencies exceeding 14% can largely be attributed to the development of nonfullerene acceptors (NFAs). Many of these molecules are structural derivatives of IDTBR and ITIC, two common NFAs. By modifying the chemical structure of the acceptor, the optical absorption, energy levels, and bulk heterojunction morphology can be tuned. However, the effect of structural modifications on NFA charge transport properties has not yet been fully explored. In this work, the relationship between chemical structure, molecular packing, and charge transport, as measured in organic thin‐film transistors (OTFTs), is investigated for two high performance NFAs, namely O‐IDTBR and ITIC, along with their structural derivatives EH‐IDTBR and ITIC‐Th. O‐IDTBR exhibits a higher n‐type saturation field effect mobility of 0.12 cm2V−1s−1compared with the other acceptors investigated. This can be attributed to the linear side chains of O‐IDTBR which direct an interdigitated columnar packing motif. The study provides insight into the transport properties and molecular packing of NFAs, thereby contributing to understanding the relationship between chemical structure, material properties, and device performance for these materials. The high electron mobility achieved by O‐IDTBR also suggests its applications can be extended to use as an n‐type semiconductor in OTFTs.

     
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