A photo-patternable and stretchable DPP-based polymer semiconductor with cinnamate containing side-chains

Polymer semiconductors with high charge mobility, robust photo-patternability and good stretchability are in high demand for flexible electronics. Herein, we report the design and synthesis of a new polymer semiconductor, PDPP4T-CIN, by introducing photoreactive cinnamate groups in the side chains. Upon UV light irradiation, PDPP4T-CIN undergoes rapid and efficient side-chain crosslinking, enabling its use as a negative photoresist for high-resolution photopatterning while preserving the backbone's electronic structure and intrinsic charge mobility. In addition, the cinnamate containing side chains modulate the thin film crystallinity, resulting in stretchability enhancement. Compared to the parent PDPP4T, PDPP4T-CIN exhibits significantly improved crack resistance and superior mobility retention under large strains and repeated stretching, demonstrating excellent mechanical robustness and device stability. This side-chain engineering strategy provides a versatile design paradigm for the development of photo-patternable, mechanically stretchable polymer semiconductors with reasonably high charge mobilities.