Organic solar cells with efficiency of 17.6% and fill factor of 78.3% based on perylene-diimide derivative as cathode interface layer

• A new organic molecule named PDINOH was synthesized and applied in OSC. • A high PCE of 17.60% and FF of 78.32% were obtained based on the OSC of PM6:Y6. • The devices showed thickness-insensitive and outstanding stability. Interface engineering is one of the methods to enhance the performances of organic solar cells (OSCs), especially cathode interface layers (CILs) are widely concerned. In the cathode interface materials, the introduction of polar groups can reduce the work function and promote electron transport by increasing the capability of cathode. In this work, we synthesized a perylene-diimide derivative ( PDINOH ) by introducing hydroxyethyl, which is conducive to extracting electrons, obtaining higher electron mobility and good interface contact with the active layer. PDINOH is employed as CIL for PM6:Y6 OSCs devices, achieving optimal power conversion efficiency (PCE) of 17.08% when the film thickness of PDINOH is 10 nm. Moreover, Treating the active layer with methanol prior to spin-coating PDINOH CIL, the devices achieved PCE of 17.60% and 16.60% at PDINOH film thicknesses of 10 nm and 34 nm, respectively. The devices showed thickness-insensitivity and outstanding stability in the absence of encapsulation. PDINOH is a more comprehensive CIL that can be applied to different systems (such as PTB7-Th:PC 71 BM, PM6:Y6, PTB7-Th:ITIC) and improved the photovoltaic performances of OSCs devices.