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.

The power conversion efficiency (PCE) of perovskite solar cells (PSCs) has seen effective performance upgrades, showing remarkable academic research and commercial application value. Compared with commercial silicon cells, the PCE gap is narrowing. However, the stability, cost, and large-scale production are still far behind. For scale-up preparing high-efficiency and stable PSCs, there is a variety of related research from each functional layer of perovskite solar cells. This review systematically summarizes the recent research on the functional layers, including the electron transport layer, perovskite layer, hole transport layer, and electrode. The common ETL materials, such as TiO2, SnO2, and ZnO, need doping and a bi-layer ETL to promote their property. Large-scale and low-cost production of perovskite layers with excellent performance and stability has always been the focus. The expensive and instability problems of Spiro-OMeTAD and electrode materials remain to be solved. The main problems and future development direction of them are also discussed.