Physical blending is a facile and effective way to improve the performance of solution processed organic thin-film transistors (OTFTs). Blending small molecule semiconductors with soluble polymers has been extensively studied in recent years. However, blending between binary small molecule semiconductors is rare due to the difficulty to obtain ideal thin films. Herein, we systematically investigate the blending effects on the morphologies of thin films and their field-effect performance by using two small molecule semiconductors, 2-phenyl[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT) and 2-(4-dodecylphenyl) [1]benzothieno[3,2-b]benzothiophene, (C12-Ph-BTBT), which have the same aromatic skeleton. Molecular ordering and better crystallinity are observed in most of spin-coated blend thin films, thanks to the enhanced molecular interaction after blending. As a result, OTFTs based on blend thin films exhibit improved performance in most cases, with the highest average hole mobility about 1.5 cm² V⁻¹ s⁻¹ demonstrated. Further device performance improvements are demonstrated by blending polystyrene with Ph-BTBT and C12-Ph-BTBT blends. The results here indicate that blending between small molecule semiconductors with compatible fused ring structures may be a promising strategy to enhance the performance of organic transistors.

物理混合是一种提高溶液处理有机薄膜晶体管（OTFT）性能的便捷有效方法。近年来，将小分子半导体与可溶性聚合物共混已得到了广泛的研究。然而，由于难以获得理想的薄膜，因此在二元小分子半导体之间的混合很少见。本文中，我们通过使用两种小分子半导体2-苯基[1]苯并噻吩并[3,2-b] [1]苯并噻吩（Ph-BTBT），系统地研究了混合对薄膜形貌的影响及其场效应性能。和具有相同芳族骨架的2-（4-十二烷基苯基）[1]苯并噻吩并[3，2-b]苯并噻吩（C12-Ph-BTBT）。在大多数旋涂共混薄膜中观察到分子有序性和更好的结晶度，混合后增强了分子相互作用。结果，基于混合薄膜的OTFT在大多数情况下表现出改进的性能，最高平均空穴迁移率约为1.5 cm²  V ^-1  s ^ ^-1证实。通过将聚苯乙烯与Ph-BTBT和C12-Ph-BTBT共混物共混，可以进一步提高器件性能。此处的结果表明，具有兼容的稠环结构的小分子半导体之间的混合可能是增强有机晶体管性能的有前途的策略。