Mixed Cation Thiocyanate-Based Pseudohalide Perovskite Solar Cells with High Efficiency and Stability.

Novel organic-inorganic hybrid perovskite compounds composed of mixed A-site cation (Formamidinium and Cesium) and pseudohalides (SCN and I) ions are successfully synthesized. These new classes of hybrid perovskites photovoltaics exhibited remarkable power conversion efficiency of more than 16% with excellent stability against moisture in ambient environment and under low-light storage condition. The existence of SCN ion inclusion is confirmed by secondary ion mass spectrometry and Fourier transform infrared spectroscopy. The SCN-doped pseudohalide is advantageous for the formation of large perovskite grains, as well as the performance and stability of the device.