Comprehensive study of the two-step solution processes in ambient air for lead iodide perovskite solar cells

Abstract

Organic-inorganic lead halide perovskite solar cells have attracted a great deal of interest because of potential low cost and high efficiency. However, in most publications, solar cells were fabricated in a highly controlled environment (glove boxes). Only a few papers reported fabrication of solar cells in air with the maximum efficiency of ∼15%. We carried out comprehensive study of the two-step solution process parameters for fabrication of perovskite solar cells in ambient air including PbL· spin coating speed, mesoporous TiO2 spin coating speed, hole transport material (HTM) spin coating speed, and HTM exposure to air etc. We found that the higher spin speed of PbI2 is critical for high-quality PbI2 film formation. The HTM exposure to air is also important to fabricate solar cells with larger current density and better fill factors.