PC61BM-based organic solar cells for indoor applications with a power conversion efficiency exceeding 20

With the development of the Internet of Things (IoT), organic solar cells (OSCs) have shown great potential for efficiently converting indoor light into electricity as a self-suitable power source for IoT systems. Fullerene and its derivatives have been widely used as electron acceptors in indoor OSCs because of their spectral matches and avoidable photodimerization. In this study, the device performance of fullerene PC61BM-based OSCs blended with three different donor polymers was investigated under indoor lighting conditions. The devices demonstrated much higher power conversion efficiencies (PCEs) under dim light conditions than under 1 sun illumination condition. The best-performing PM6:PC61BM normal OSCs exhibited a maximum PCE of 7.94% under 1 sun illumination and 23.27% under a 3200 K light -emitting diode (LED) at 2000 lx. This study suggests the favorable applicability of fullerene-based OSCs for indoor applications and highlights the importance of good spectral matches and energy-level alignment for efficient indoor OSCs. •The fullerene derivative PC61BM as the electron acceptor has high electron mobility.•The PM6:PC61BM film shows better spectral matches and energy-level alignment.•The best-performing OSCs achieved a maximum PCE exceeded 23% under a LED at 2000 lx.