Improving the Morphological and Optical Properties of the CsPbBr3 Films by PbI2 Substitution for Efficient All-inorganic Perovskite Solar Cells

Abstract

Wide band gap CsPbBr₃ perovskite solar cells are becoming one of the ideal candidates for top cells in tandem solar cells. Nevertheless, the defects in CsPbBr₃ film prepared by solution deposition method restrict the optoelectronic performance of perovskite solar cells. To solve this problem, a strategy of doping a trace amount of PbI₂ into CsPbBr₃ film synthesized by solution deposition is adopted, effectively increasing the average grain size of CsPbBr₃ film, decreasing its optical band gap, number of surface grain boundary defects and carrier recombination probability. Simultaneously, the PbI₂-doped CsPbBr₃ perovskite solar cells have been successfully prepared. The best conversion efficiency of the CsPbBr₃ cells with doping PbI₂ is 6.46 %, which is higher than the efficiency of the undoped CsPbBr₃ devices (5.00 %). This study offers a method for manufacturing highly efficient all-inorganic perovskite solar cells.