Recent advances of non-fullerene organic solar cells: From materials and morphology to devices and applications

The innovation of non-fullerene acceptors (NFAs) enables the rapid progress of organic solar cells (OSCs) in power conversion efficiencies to over 19%, endowing OSCs with great potential toward real-world application. In this critical review, we outline the recent advances of NFA-based OSCs - from ITIC- to Y6-family, to exemplify the structure-performance correlations, and cover from material chemistry to nanomorphology controlling. In addition, we point out the possible degradation mechanisms behind the NFA-based devices and strategies for mitigating the stability issues. With OSC efficiencies approaching 20% benchmark, increasing attention has been built-up toward the technology's applications. Therefore, we describe the opportunities and challenges in the promising applications, mainly on semitransparent and flexible OSCs for commercial photovoltaics. Finally, we provide a summary and perspective to point out the primary challenges the OSC technology is facing toward commercialization.