KI interface modification improves efficiency of perovskite solar cells

The planar-structured perovskite solar cell was prepared through addition of KI intercalation layer between the SnO2 electron transport layers(ETLs)/perovskite layer prepared at low temperature. The interfacial modification effect of KI intercalation layer for the SnO2 ETLs/perovskite layer, and the influences on the properties of perovskite film and the device performance of perovskite solar cells were investigated. The results show that the addition of KI interlayer facilitates the grain growth of perovskite film and thus improves the interfacial carrier transport efficiency at ETLs/perovskite absorber. Herein, the overall performances, especially the power conversion efficiency, for both rigid and flexible solar cells are significantly optimized after the involvement of KI interlayer, mainly due to the improved open-circuit voltage(Voc) and fill factor(FF), despite the short-circuit current density(Jsc) slightly decreases. The average power conversion efficiencies of rigid devices and flexible ones increase from 17.71% and 14.52 % to 18.46% and 17.46 %, respectively. © 2022 Central South University of Technology. All rights reserved.