Department of Applied Chemistry and Center for Future Innovation (CFi), Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan.
J Phys Chem Lett. 2023 Apr 13;14(14):3461-3467. doi: 10.1021/acs.jpclett.3c00334. Epub 2023 Apr 3.
Organic semiconductors are well-known to exhibit high charge carrier mobility based on their spread of the π-orbital. In particular, the π-orbital overlap between neighboring molecules significantly affects their charge carrier mobility. This study elucidated the direct effect of subtle differences in the π-orbital overlap on charge carrier mobility, by precisely controlling only molecular arrangements without any chemical modifications. We synthesized disulfonic acid composed of a [1]benzothieno[3,2-][1]benzothiophene () moiety, and prepared organic salts with four butylamine isomers. Regardless of the type of butylamine combined, electronic states of the constituent derivative were identical, and all arrangements were edge-to-face herringbone-type. However, depending on the difference of steric hindrance, center-to-center distances and dihedral angles between neighboring moieties slightly varied. Despite a similar arrangement, the photoconductivity of four organic salts differed by a factor of approximately two. Additionally, theoretical charge carrier mobilities from their crystal structures exhibited a strong correlation with their photoconductivity.
有机半导体因其π轨道的扩展而表现出高电荷载流子迁移率是众所周知的。特别是，相邻分子之间的π轨道重叠对其电荷载流子迁移率有显著影响。本研究通过精确控制仅分子排列而不进行任何化学修饰，阐明了π轨道重叠的细微差异对电荷载流子迁移率的直接影响。我们合成了由[1]苯并噻吩[3,2-][1]苯并噻吩（）部分组成的二磺酸，并制备了四种正丁胺异构体的有机盐。无论结合的正丁胺类型如何，组成的 衍生物的电子态都是相同的，所有的 排列都是边缘到面对面的鲱鱼骨型。然而，由于空间位阻的差异，相邻 部分之间的中心到中心距离和二面角略有不同。尽管排列相似，但四种有机盐的光电导性相差约两倍。此外，从晶体结构计算出的理论电荷载流子迁移率与其光电导性表现出很强的相关性。
