Doping with SnBr2 in CsPbBr3 to enhance the efficiency of all-inorganic perovskite solar cells

Abstract

The good environmental stability of all-inorganic CsPbBr₃ perovskite solar cells is crucial for the commercialization of perovskite solar cells. In this paper, an efficiency improvement from 6.85% to 8.63% is achieved by doping SnBr₂ into the CsPbBr₃ light absorbing layer in FTO/c-TiO₂/m-TiO₂/CsPbBr₃/carbon perovskite solar cells. By doping with SnBr₂, the CsPbBr₃ perovskite light absorbing layer is more continuous and nonporous, and the charge transport of the CsPbBr₃ layer doped with SnBr₂ is accelerated. The SnBr₂ incorporation also modifies the band structure of the CsPbBr₃ perovskite material so that the valence band energy level shifts from −5.6 eV to −5.46 eV. As a result, the energy level between the carbon electrode and the light absorbing layer is more matched, facilitating the charge transport of holes from the light absorbing layer to the carbon electrode. This work highlights a doping method in CsPbBr₃ to enhance the solar cell performance.