Stability of Intrinsically Stretchable Polymer Photovoltaics: Fundamentals, Achievements, and Perspectives

Stretchable organic photovoltaics have recently garnered significant attention as promising power sources for wearable electronic systems. Especially, research on intrinsically stretchable organic photovoltaics (IS-OPVs) has been accelerated, as the unique advantage of IS-OPVs is their inherent deformability, which does not depend on fabrication processes or pre-treatment methods. Remarkably, the photoactive area increases during stretching, indicating a potential increase in power output and underscoring IS-OPV's strengths as a power source in self-powered electronic systems. Despite rapid advancements in power conversion efficiency and stretchability, IS-OPVs still encounter challenges in market adoption. The most critical performance factor for IS-OPVs is stability, which ensures stable operation under mechanical stress. This review analyses the structural factors that degrade the stability of IS-OPVs. Given their multilayer structure, mechanical failure can result from various complex causes, thus complicating the investigation and comprehensive understanding of the factors that promote performance degradation. This review introduces and discusses recently developed engineering strategies aimed at improving the mechanical stability of IS-OPVs. Furthermore, this review summarizes various experimental methods to assess the performance of IS-OPVs and discusses the insights gained from these experiments in relation to fabricating mechanically stable IS-OPVs with enhanced performance.