High-Efficiency Indoor Organic Photovoltaics with a Band-Aligned Interlayer

The emergence of indoor electronic devices for internet of things (IoT) has motivated the scientific community to develop photovoltaic devices that can efficiently convert indoor light into electricity. In this paper, we report high-efficiency non-fullerene organic photovoltaic (OPV) cells with over 30% power conversion efficiency (PCE) under indoor conditions. Our results show that the choice of electron-transporting layer (ETL) is critically important to enable such performance. The use of an ETL (named PDI-NO) with a deep highest occupied molecular orbital (HOMO) level can effectively suppress leakage current and reduce trap-assisted recombination of the devices. Thus, using this ETL, we achieve record PCE of 31% by utilizing a low-band-gap acceptor in the bulk-heterojunction (BHJ) blend. Whereas, in another case, by employing a large-band-gap acceptor, a PCE of 26.7% with over 1V is achieved. Our study paves the way toward high-performance indoor OPV devices for powering IoT electronics.