Highly Stable All-Inorganic Pb-Free Perovskite Solar Cells

Abstract

Thermally stable planar Pb-free Cs3Bi2I9 perovskite solar cells were fabricated using glass, ITO, ZnO, Cs3Bi2I9, Cul, and Au as the transparent substrate, transparent conducting electrode, electron-transporting layer, light absorption layer, hole-transporting layer, and counter electrode, respectively. Planar Cs3Bi2I9 perovskite solar cells with a Cul hole-transporting layer produced a power conversion efficiency of 9.0 and 9.2% at an illumination of 1 sun (100 mW/cm(2)) for forward and reverse scans, respectively. They also maintained their initial efficiency following heat treatment at 200 degrees C in air due to the high thermal stability of Cul, whereas Cs3Bi2I9 perovskite solar cells with a poly-triarylamine hole-transporting layer exhibited a rapid degradation in power conversion efficiency.