Improved characteristics of a perovskite solar cell by the annealing process and UV irradiation on the TiO2 layer

Abstract

In this study, we focused on the changes on the perovskite layer by annealing. A two-step annealing process, which changes the temperature and time in the annealing process of the perovskite film, is important to obtain a more efficient solar cell. The perovskite synthesis proceeds rapidly, but a significant amount of lead iodide residue remains. Additional annealing is needed to reduce the lead iodide residue that causes degradation in efficiency. A solar cell with an average efficiency of 14.3% and a maximum efficiency of 14.58% was fabricated when it was annealed at 150 °C for 10 min and further annealed at 120 °C for 40 min. In addition, when the TiO2 layer was irradiated with UV light at 185 and 254 nm for 20 min, a perovskite solar cell with an average efficiency of 14.8% and a maximum efficiency of 15.04% was obtained.