Recent Progress on Boosting the Perovskite Film Quality of All-Inorganic Perovskite Solar Cells

All-inorganic CsPbX3 perovskite material not only has the benefits of advanced light absorption coefficient, long carrier lifetime, and simple preparation process of organic–inorganic perovskite materials but it also maintains excellent stability under the erosion of damp heat. Stability is the premise of its industrialization, so all-inorganic perovskite is undoubtedly a very competitive direction for the development of perovskite materials. However, there are still many defects in the all-inorganic perovskite thin films, and it is difficult to obtain high power conversion efficiency (PCE). This review systematically summarizes additive engineering, solvent engineering, and interface engineering methods to promote the thin film property for a high PCE in recent years.