Interconnecting semiconducting molecules with non-conjugated soft linkers: a way to improve film formation quality without sacrifice in charge mobility

Wen-Jing Xiao; Jiandong Wang; Hong-Jiao Li; Long Liang; Xuan Xiang; Xue-Qiang Chen; Jingjing Li; Zhengquan Lu; Wei-Shi Li

doi:10.1039/c8ra04405h

Interconnecting semiconducting molecules with non-conjugated soft linkers: a way to improve film formation quality without sacrifice in charge mobility

RSC Adv. 2018 Jun 28;8(42):23546-23554. doi: 10.1039/c8ra04405h. eCollection 2018 Jun 27.

Authors

Wen-Jing Xiao¹, Jiandong Wang¹, Hong-Jiao Li¹, Long Liang¹, Xuan Xiang¹, Xue-Qiang Chen¹, Jingjing Li², Zhengquan Lu², Wei-Shi Li^{1

2}

Affiliations

¹ Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China liws@mail.sioc.ac.cn.
² Engineering Research Center of Zhengzhou for High Performance Organic Functional Materials, Zhengzhou Institute of Technology 6 Yingcai Street, Huiji District Zhengzhou 450044 China.

Abstract

The formation of high quality homogeneous active component films is essential to the fabrication of many organic optoelectronic devices, especially those having a large area module. However, most small molecule (SM) semiconductors are unable to achieve such a goal via solution processing because their large and rigid π-conjugated structures generally drive them to aggregate or crystallize into inhomogeneous domains in the process. In this work, a SM semiconductor (SM-DPP6T) based on a diketopyrrolopyrrole (DPP) center with three thiophene units on both sides encounters the same problem. However, when its molecules are interconnected with soft alkyl linkers and change into a poly(rod-coil) polymer, PRC-DPP6T, the problem is solved. Compared with SM-DPP6T, PRC-DPP6T can form a high quality homogeneous film with much better uniformity and coverage on silicon wafers by spin-coating. Moreover, the so-prepared PRC-DPP6T field-effect transistors displayed a much narrower performance distribution and comparable mobility when compared with those based on SM-DPP6T (0.17 vs. 0.15 cm² V^-1 s^-1). These results demonstrate that the interconnection of SM semiconductor molecules with soft non-conjugated linkers is a promising way to improve film formation quality while keeping mobility intact.