Realizing n-Type Field-Effect Performance via Introducing Trifluoromethyl Groups into the Donor–Acceptor Copolymer Backbone

作者：Congyuan Wei, Weifeng Zhang, Jianyao Huang, Hao Li, Yankai Zhou, Gui Yu · 发表于：Macromolecules · 年份：2019 · DOI：10.1021/acs.macromol.9b00022 · 被引用次数：28 · 研究领域：Organic Electronics and Photovoltaics、Conducting polymers and applications、Perovskite Materials and Applications

Developing a new strategy to obtain n-type organic semiconductors is crucial for the advance of organic electronics. We herein report the synthesis and investigation of a series of donor–acceptor-type diazaisoindigo-based copolymers, named PAIID-TFBVB-C1, PAIID-TFBVB-C3, and PAIID-BVB-C3 . After introduction of the trifluoromethyl groups with strong electron-withdrawing ability into the molecular backbone of PAIID-BVB-C3 -containing stilbene units, the obtained polymer PAIID-TFBVB-C3 shows obvious blue-shifted UV–vis absorption profiles because of the enlarged band gap revealed by the theoretical simulation. Meanwhile, both the energy levels of the lowest unoccupied molecular orbital (LUMO) of PAIID-TFBVB-C1 and PAIID-TFBVB-C3 with trifluoromethyl groups are lower than that of PAIID-BVB-C3 without trifluoromethyl groups, reducing the energy difference between the LUMO energy level and the work function of the source-drain electrode and further facilitating electron injection. Consequently, both the PAIID-TFBVB-C1 - and PAIID-TFBVB-C3 -based devices show typical n-type field-effect performance with electron mobilities of 0.11 and 0.04 cm 2 V –1 s –1, respectively, whereas devices based on PAIID-BVB-C3 exhibit p-type semiconducting performance with a hole mobility of 0.14 cm 2 V –1 s –1 . Our results demonstrate that it is a feasible strategy to acquire n-type semiconducting materials by introducing the electron-withdrawing trifluoromethyl groups into the polymer backbone.