▎ 摘　　要

We previously developed perovskite/graphene solar cells with improved long-term stability. In this study, we investigated the effect of the number of layers on the characteristics of a solar cell by changing the number of graphene layers and further determined the optimum number of graphene layers. We showed that the interfacial recombination due to the damaged layer of the outermost perovskite layer and the band bending of the perovskite layer due to the change of the work function of graphene had a significant influence on the characteristics of the solar cell, especially the short-circuit current. A conversion efficiency of up to 9.4% was obtained as a result of optimizing the formation conditions of the perovskite layer with seven graphene layers. (C) 2020 The Authors. Published by Elsevier Ltd.