Engineering inorganic lead halide perovskite deposition toward solar cells with efficiency approaching 20%

Abstract Inorganic perovskite materials have gained tremendous attention due to their superior chemical and thermal stability than organic‐inorganic hybrid perovskites. In the past years, substantial research efforts have been devoted to developing uniform and pin‐hole free inorganic perovskite films with high electronic quality. As a result, power conversion efficiency of inorganic perovskite solar cells (PSCs) has boosted to over 19%, which presents a promising potential for technology commercialization. Herein, we give a comprehensive review of the recent progress on state‐of‐the‐art inorganic cesium lead halide based PSCs, particularly on the perovskite deposition approaches. We show a clear roadmap to fabricate high electronic quality inorganic perovskite films by tuning the precursor crystallization kinetics, performing post‐deposition treatments, and passivating surface/interface defects. Inorganic perovskite films prepared by these approaches exhibit not only high crystallinity, favorable morphology, and low trap densities but also improved phase stability. The advanced deposition approaches lay the foundation for further improving the performance and long‐term operational stability of inorganic perovskite photovoltaics.