Optimized Organometal Halide Perovskite Planar Hybrid Solar Cells via Control of Solvent Evaporation Rate

Organometallic halide perovskite-based solar cells have exhibited rapidly increasing efficiencies through the use of mesoporous composites. The addition of materials used in organic solar cells to perovskite-based solar cells (PSCs) enables the fabrication of low-cost, flexible, low-temperature, solution-processed PSCs. However, obtaining sufficient coverage of the organic layer, usually poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonate) (PEDOT:PSS), with CH3NH3PbI3–xClx films remains difficult in spite of the advances. In this study, we investigated the influence of controlling the solvent evaporation rate on the degree of PEDOT:PSS surface coverage by CH3NH3PbI3–xClx. We determined that an adequately fast spinning speed, drying at room temperature, and stepwise ramp annealing are critical for obtaining optimized planar hybrid perovskite solar cells with an ITO/PEDOT:PSS/CH3NH3PbI3–xClx/PCBM/Al structure and efficiencies of up to 11.8%.