He Zhengran, Zhang Ziyang, Bi Sheng, Chen Jihua, Li Dawen
Department of Electrical and Computer Engineering, The University of Alabama, Tuscaloosa, AL, 35487, USA.
Department of Electrical Engineering, Columbia University New York City, New York City, NY, 10027, USA.
Sci Rep. 2020 Mar 9;10(1):4344. doi: 10.1038/s41598-020-61282-x.
In this study, we report an effective approach to tune the crystallization, microstructure and charge transport of solution-processed organic semiconductors by blending with a conjugated polymer additive poly(3-hexylthiophene) (P3HT). When 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) was used as a model semiconductor material to mix with different amount of P3HT, their intermolecular interactions led to distinctive TIPS pentacene film morphologies, including randomly-oriented crystal ribbons, elongated needles with enhanced long-range order, and grass-like curved microwires with interlinkages. Each type of morphology was found to further correlate to considerably different charge transport and device performance. As compared to pristine TIPS pentacene devices, bottom-gate, top-contact OTFTs with 2% in weight P3HT additive showed a 2-fold and 5-fold improvement of average field-effect mobility and performance consistency (defined as the ratio of average mobility to the standard deviation), respectively. The improvement in transistor electrical performance can be attributed to the combined effect of enhanced crystal orientation and uniformity, as well as increased areal coverage. This work can be applied beyond the particular example demonstrated in this study and to tune the charge transport of other small-molecule organic semiconductors in general.
在本研究中，我们报道了一种通过与共轭聚合物添加剂聚（3-己基噻吩）（P3HT）共混来调节溶液处理有机半导体的结晶、微观结构和电荷传输的有效方法。当使用6,13-双（三异丙基甲硅烷基乙炔基）并五苯（TIPS并五苯）作为模型半导体材料与不同量的P3HT混合时，它们的分子间相互作用导致了独特的TIPS并五苯薄膜形态，包括随机取向的晶体带、具有增强长程有序性的细长针状以及具有互连的草状弯曲微丝。发现每种形态都与截然不同的电荷传输和器件性能进一步相关。与原始TIPS并五苯器件相比，添加2%重量的P3HT添加剂的底栅、顶接触有机薄膜晶体管（OTFT）的平均场效应迁移率和性能一致性（定义为平均迁移率与标准偏差之比）分别提高了2倍和5倍。晶体管电学性能的提高可归因于晶体取向和均匀性增强以及面积覆盖率增加的综合效应。这项工作不仅适用于本研究中展示的特定示例，一般而言还可用于调节其他小分子有机半导体的电荷传输。
