Hybrid sequential processing of mixed Sn-Pb narrow-bandgap perovskite solar cells

Hybrid vapor-solution sequential deposition of perovskites is a well-established method that enables large-area processing of perovskite films and solar cells. In this study, for the first time, we applied the hybrid sequential deposition method to the fabrication of narrow-bandgap mixed Sn-Pb perovskite films. We obtained compact, large-grained perovskite films with power conversion efficiency values exceeding 10% under 1 sun illumination with hole-transport-material-free devices. The applied method eliminates the oxidative degradation risks of solvents during perovskite formation and provides an easy way to develop additive and passivation strategies to improve photovoltaic properties.