Side Chain Modulation Enables High-Performance Quinoid–Donor–Acceptor Terpolymer Transistors Processed with Nonhalogenated Solvents

The quinoid–donor–acceptor (Q–D–A) strategy holds immense promise for constructing high-performance conjugated polymers used in organic field-effect transistors (OFETs). Achieving optimal interchain aggregation through simple molecular-level engineering to balance solubility and molecular packing is pivotal for enhancing OFET performance, particularly with environmentally friendly processing. Herein, a side chain modification approach is pioneered within the Q-D-A system to delicately control aggregation and optimize microstructure, enabling high-performance OFETs processed with nonhalogenated solvents. A series of Q-D-A terpolymers with identical backbones but varying ratios of branched to linear alkyl chains were designed and synthesized, facilitating a systematic investigation into their aggregation behavior, solubility, crystallinity, and OFET performance. Experimental and theoretical analyses reveal that increasing the linear alkyl chain content minimally affects electrochemical properties but gradually improves backbone coplanarity and enhances aggregation strength while decreasing the solubility. The terpolymer PAQM-BT-15, with 15% linear alkyl chains, exhibits the highest crystallinity and lowest lattice disorder when processed from chlorobenzene, achieving a record-setting reliable hole mobility of 6.13 cm2 V–1 s–1 for quinoidal conjugated polymers. Notably, PAQM-BT-15-based OFETs processed with o-xylene, a nonhalogenated solvent, deliver remarkable operational stability and an outstanding hole mobility of 3.02 cm2 V–1 s–1, ranking among the highest for conjugated polymers processed with nonhalogenated solvents. These results represent a significant advance in the development of high-performance Q-D-A polymers via environmentally friendly processing, with broad implications for the design of conjugated polymers in sustainable organic electronic.