Strategy for enhancing photostability of inverted organic photovoltaics via molecular engineering of non-fullerene acceptors

Abstract

With emergence of the non-fullerene acceptors (NFAs), organic photovoltaics (OPVs) have been developed rapidly achieving unprecedented power conversion efficiency (PCEs) of 20%. Despite this prodigious progress in OPVs, there are still challenges in securing photostability of OPVs remained, which needs to be resolved to push the OPV technology further into real-life application. Here we synthesized m-ITIC-OEH-based NFAs to investigate the possible origins of the degradation of OPVs with inverted architecture under continuous illumination. By modifying the end groups of NFAs, we retarded the morphological change during light illumination, resulting in the extended lifetime of OPVs more than 6 times. From our works, we believe that our findings suggest bright insight into molecular design of NFA for photostable OPVs.