Unraveling the Reasons for Efficiency Loss in Perovskite Solar Cells

Abstract

The effect of the presence of unreacted PbI 2 on the perovskite solar cells efficiency is reported. N,N-Dimethylformamide vapor treatment is introduced to study the influence of complete conversion to a power conversion efficiency of the device. It is discovered that the optimized morphology of the PbI 2 under layer is essential to form a dense perovskite layer preventing recombination by direct contact between TiO 2 and a hole transporting layer, and to increase the charge collection efficiency. The present findings provide an insight into the morphology and growth mechanism of perovskite layer, the correlation between the device performance, and the film deposition process.