Cesium-Containing Methylammonium Lead Iodide Light Absorber for Planar Perovskite Solar Cells

Institute of Materials, Chinese Academy of Engineering Physics, Jiangyou 621908, P. R. China To improve the stability of organic–inorganic hybrid perovskite, cesium-containing methylammonium lead iodide perovskite have been synthesized by one-step solution deposition. With the increasing of Cs⁺ doping concentration, direct optical band gap of perovskite was increases, while defects and roughness of perovskite thin films were gradually augmented. A certain amount of Cs⁺ incorporated in perovskite absorb layer could improve power conversion efficiency through the enhancing of open circuit voltage and fill factor. However, excessive Cs⁺ doping concentration results in the reduced of short-circuit current and fill factor, which reduced power conversion efficiency. The optimized ratio 10% Cs⁺ doping achieved the highest power conversion efficiency (16.84%).