Abstract

Conjugated terpolymers emerge as promising candidates to develop wearable and stretchable electronics for the merits of mechanical stretchability and high charge mobility. Despite their potential, backbone structural diversity causes significant variability and limited predictability in their electrical stretchability, hindering their rational design. Here, we report a rational design on the backbone structure for high-performance stretchable terpolymers. We study a novel group of terpolymers, DPP-mSe-nTz, with varying ratios of two co-monomer units. The frontier molecular orbital exhibits higher delocalization length with the increased ratio of DPP-Se segments. Accordingly, terpolymers with extended frontier molecular orbital exhibit superior electrical performance under strain. The optimized terpolymer (DPP-75Se) exhibits high hole mobility of 0.29 cm^2/(Vs) and high retention of 28% under 100% strain. Combining observation on the morphology evolution and computational analysis of charge transport, we propose a comprehensive understanding of frontier molecular orbital delocalization in enhancing the electrical stretchability of terpolymers.