Influence of CsPbBr3/TiO2 interfaces deposited with magnetron sputtering and spin-coating methods on the open voltage deficit and efficiency of all-inorganic CsPbBr3 planar solar cells

The mechanism of open voltage (Voc) deficit in all-inorganic CsPbBr3 planar solar cell has been systematically investigated by depositing the TiO2 electron transport layer with magnetron sputtering (MS) and spin-coating (SC) deposition, respectively. It was found that SC-TiO2 film reveals higher optical band gap (3.67 eV) than MS-TiO2 film (3.62 eV). However, CsPbBr3 planar solar cell based on MS-TiO2 exhibits less Voc deficit and higher photoelectric conversion efficiency (5.48%). The mechanism behind performance enhancement of MS-TiO2-based device is suitable Fermi level of MS-TiO2 and high electronic transport capacity with low charge recombination at CsPbBr3/MS-TiO2 interface. Moreover, the unencapsulated all-inorganic planar devices show a superior stability when stored in air at room temperature for two months. This work provides a novel approach to improve the performance of all-inorganic perovskite solar cell.