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

摘要

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 FA_(0.8)Cs_(0.2)PbI_(2.68)Br_(0.32) 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.