Precisely Regulating Interchain Aggregation and Film Crystallinity of Quinoidal Terpolymers for High-Performance Eco-friendly Transistors

The widespread use of toxic halogenated solvents in processing high-performance conjugated polymers raises environmental concerns and hinders large-scale organic electronics production. While the terpolymer approach has improved the donor–acceptor polymer performance, it remains unexplored in quinoidal systems. This study pioneers a terpolymer strategy for quinoidal polymers to enable eco-friendly processing by fine-tuning interchain aggregation and film crystallinity, leading to improved charge mobility and stability in organic field-effect transistors (OFETs). A series of para-azaquinodimethane-based random terpolymers with varied ratios of terthiophene (3T) and quaterthiophene (4T) units are developed, demonstrating that higher 4T content enhances interchain aggregation but reduces solubility, dramatically affecting molecular packing and OFET performance. When processed from chlorobenzene, all terpolymers outperformed reference alternating copolymers, with PA-3T25-4T75 containing 75% 4T achieving the highest hole mobility of 2.26 cm2 V–1 s–1 due to its most ordered microstructure. Notably, PA-3T75-4T25 with 25% 4T achieves an impressive hole mobility of 2.09 cm2 V–1 s–1 with tetrahydrofuran as the solvent, marking a record high value for quinoidal polymers processed from eco-friendly solvents. This work underscores the potential of terpolymer design in enhancing both OFET performance and environmental sustainability of quinoidal polymers, contributing to the development of eco-friendly organic electronics.