Fabricating High‐Efficient Blade‐Coated Perovskite Solar Cells under Ambient Condition Using Lead Acetate Trihydrate

Heat‐assisted blade‐coating (HABC) technique can be applied for scalable production of perovskite solar cells (PSCs). With the current setups, HABC is not applicable in ambient atmosphere due to the adverse impact of humidity on perovskite films. Here, a modified HABC method is reported to achieve high quality perovskite films under harsh ambient conditions. By using lead acetate trihydrate (PbAc 2 · 3H 2 O) as the lead source, a rapid low‐temperature, short time annealing treatment is discovered. It is found that a small amount of hydrate water in PbAC 2 · 3H 2 O lead source lead to dense and oriented nuclei at the blade‐coating stage. The concomitant MAPbI 3 · x H 2 O on the surface and grain boundaries of perovskite films isolates the moisture in ambient during the annealing process, melts to form a quasi‐liquid nutrition pool for the cultivation of MAPbI 3 grain domains via Ostwald ripening. The as‐prepared perovskite films consist of large grain domains of up to 100 μm, which are highly orientated. Based on these films, the conversion efficiency of PSCs reaches 15.8 ± 0.6%, a jump of nearly 40% compared with that of PbAc 2 ‐sourced devices (11.4 ± 1.0%). The robust strategy presented here is a significant contribution towards scalable production of high efficiency PSCs under ambient condition.