Recent Progress on Applications of Nano Metal Oxides in Perovskite Solar Cells

In recent years, the power conversion efficiency of perovskite solar cells (PSCs) has increased dramatically from 3.8% to 20.1%, approaching to that of recent silicon-based solar cells. Inorganic metal oxides, including TiO 2 , ZnO, Al 2 O 3 , etc., have been widely used as charge transport layers and perovskite supporting scaffords in PSCs. Regarding the cell structures of PSCs, this review discusses the syntheses methods of inorganic compact layers and mesoporous layers made from these inorganic metal oxides, and the modifications (including surface modifications, doping and composites) of these inorganic functional layers, which aim at improving the charge transport properties of these layers and changing the interfacial characteristics with perovskites to enhance the PSCs' cell performances. Besides, the important issues of such functional layers made from inorganic metal oxides are also discussed.