When Assembly Meets Processing: Tuning Multiscale Morphology Of Printed Conjugated Polymers For Controlled Charge Transport

Conjugated polymers are rapidly emerging as an attractive class of semiconductors for next-generation electronics thanks to their low-cost, high-throughput solution processability, mechanical flexibility, stretchability, self-healing properties, and ability to interface and communicate with biological systems. Accordingly, the last four decades has seen a surge of studies that have provided seminal contributions to the thorough understanding of conjugated polymers. One of the key factors that dictates the electronic performance of conjugated polymers is their assembly and crystallization behavior, which has remained intriguing and challenging to study. The complex solution processing environment and rapid kinetics strongly couple with the conjugated polymer assembly process, further complicating a full mechanistic picture. In this perspective, we summarize the charge transport mechanism, fundamentals of conjugated polymer assembly, and solution printing. We further discuss central strategies that have been developed to control and enhance their multiscale assembly during solution printing. Finally, we hope that our perspective will stimulate more studies on how processing can control morphology and charge transport of conjugated polymers and applications of these concepts to other advanced functional materials.