Mixed cations and mixed halide perovskite solar cell with lead thiocyanate additive for high efficiency and long-term moisture stability

The commercialization of organic-inorganic hybrid perovskite solar cells (PSCs) has been impeded by their structural instability and susceptibility towards moisture. We demonstrate the fabrication of mixed cation lead mixed halide FA0.8Cs0.2PbI2.68Br0.32 perovskite solar cells with long-term stability by addition of the Pb(SCN)2 additive. The introduction of Pb(SCN)2 improves the crystallinity of perovskite to promote the generation of high-quality film. The perovskite films with Pb(SCN)2 exhibit large grain-size, less pinholes, reduced trap density and prolonged charge carrier lifetime. The PSCs with 2 mol % Pb(SCN)2 fabricated in ambient environment have showed notable power conversion efficiency (PCE) of 17.0% with less hysteresis and remarkably high moisture stability. The PCE of unsealed devices maintained 85.1% of the initial value under ambient environment (60 ± 5% RH) after 45 days.