Charge Polarity Modulation and Efficient Electron Transport in Quinoid–Donor–Acceptor Polymers by Acceptor Engineering for High-Performance Transistors
Hao Chen, Runze Xie, Jie Tang, Xuanchen Liu, Xuanchen Liu, Jinlun Li, Cheng Liu, Yunfeng Qiang, Chen Yang, Lianjie Zhang, Junwu Chen, Xuncheng Liu, Xuncheng Liu
Abstract
Fine-tuning the charge polarity and enhancing electron transport in conjugated polymers are critical for developing high-performance organic field-effect transistors (OFETs). Quinoidal polymers, characterized by planar backbones and deep-lying lowest unoccupied molecular orbital (LUMO) energy levels, offer distinct advantages over their aromatic counterparts but face challenges in achieving reliable electron mobilities exceeding 1 cm 2 V –1 s –1 . Herein, we synthesized and characterized a set of novel quinoid–donor–acceptor (Q-D-A) polymers with various acceptor units. Increasing acceptor strength narrowed the band gap, lowered LUMO levels, and shifted charge polarity from unipolar p -type to ambipolar and ultimately to dominant n -type behavior. The electron-to-hole mobility ratio increased from 0 to 40 with electron transport behavior observed in a Q-D-A polymer for the first time. Consequently, the strongest acceptor-based polymer exhibited a planar backbone, small electron effective mass, high crystallinity, and low disorder, resulting in a reliable electron mobility of 1.20 cm 2 V –1 s –1 with decent operational stability. This mobility is a record-high value for quinoidal polymers with reliable electron transport. Our findings offer a viable strategy for tuning charge polarity and improving n -type transport in quinoidal polymers, providing insights into the structure–property relationships essential for advancing high-performance organic electronics.