The properties of perovskite solar cells with novel MAPbBr₃/CsPbBr₃ double absorber

Abstract Perovskite solar cells (PSCs) based on CsPbBr 3 have garnered considerable attention due to their high stability and all-inorganic components. Although thermal annealing is a conventional and effective method to improve the quality of CsPbBr 3 films, property improvement strategies are still scarce, especially for the vapor deposition process. In this work, a MAPbBr 3 layer is introduced at the TiO 2 and CsPbBr 3 interface to construct a double-absorber heterojunction structure. It is found that the cubic phase of CsPbBr 3 is formed directly on the MAPbBr 3 underlayer due to the epitaxial growth. Furthermore, the heterojunction formed at the MAPbBr 3 /CsPbBr 3 interface contributes to the superior extraction of the light-generated carriers. A power conversion efficiency (PCE) of 6.53% is obtained for the PSC with a double-absorber design. Despite the thickness of the epitaxial layer being shrunken after annealing at 150 °C for 30 min, a PCE of 5.90% is achieved, indicating the high thermal stability of the double-absorber device. Our work provides a new insight into quality engineering for the perovskite deposited by the vapor deposition process.