Chain Alignment and Film Crystallinity Manipulation Towards High-Performance Large-Area Printed Stretchable Electronics
Scalable printing of stretchable conjugated polymer films is essential for low-cost, large-area wearable electronics, yet achieving optimal film morphology that simultaneously enhances energy dissipation and charge transport remains a critical challenge. This study demonstrates large-area stretchable conjugated polymer films with low crystallinity but strong chain alignment, fabricated by simultaneously regulating fluid field and solidification dynamics during bar-coating. The strong fluid field aligns polymer chains in the coating direction and promotes solution aggregation in the initial wet layer, while sequential rapid solidification restricts crystallization and facilitates aggregate alignment, forming highly-aligned nanofiber networks within the elastomer phase. These elastomer-constrained nanofiber networks maintain connectivity under strain, providing efficient charge transport channels. The resulting films exhibit high charge mobilities of 6.11 and 2.98 cm2 V−1 s−1 at 0% and 100% strains, respectively, among the highest reported for stretchable conjugated polymer films. The films also achieve a high X-ray sensitivity of 1757.2 μC Gyair−1 cm−2 and an ultralow detection limit of 72.5 nGyair s−1, with maintained imaging capability before and after stretching. This work establishes a robust morphology control strategy for high-performance, large-area stretchable conjugated polymer films, advancing their practical application in wearable electronics.