A Semi‐Crystalline Polymer Semiconductor with Thin Film Stretchability Exceeding 200%

Abstract Despite the emerging scientific interest in polymer‐based stretchable electronics, the trade‐off between the crystallinity and stretchability of intrinsically stretchable polymer semiconductors—charge‐carrier mobility increases as crystallinity increases while stretchability decreases—hinders the development of high‐performance stretchable electronics. Herein, a highly stretchable polymer semiconductor is reported that shows concurrently improved thin film crystallinity and stretchability upon thermal annealing. The polymer thin films annealed at temperatures higher than their crystallization temperatures exhibit substantially improved thin film stretchability (> 200%) and hole mobility (≥ 0.2 cm 2 V −1 s −1 ). The simultaneous enhancement of the crystallinity and stretchability is attributed to the thermally‐assisted structural phase transition that allows the formation of edge‐on crystallites and reinforces interchain noncovalent interactions. These results provide new insights into how the current crystallinity–stretchability limitation can be overcome. Furthermore, the results will facilitate the design of high‐mobility stretchable polymer semiconductors for high‐performance stretchable electronics.