Defect-Engineering-Enabled High-Efficiency All-Inorganic Perovskite Solar Cells.

The emergence of cesium lead iodide (CsPbI3) perovskite solar cells (PSCs) has generated enormous interest in the photovoltaic research community. However, in general they exhibit low power conversion efficiencies (PCEs) because of the existence of defects. A new all-inorganic perovskite material, CsPbI3:Br:InI3, is prepared by defect engineering of CsPbI3. This new perovskite retains the same bandgap as CsPbI3, while the intrinsic defect concentration is largely suppressed. Moreover, it can be prepared in an extremely high humidity atmosphere and thus a glovebox is not required. By completely eliminating the labile and expensive components in traditional PSCs, the all-inorganic PSCs based on CsPbI3:Br:InI3 and carbon electrode exhibit PCE and open-circuit voltage as high as 12.04% and 1.20 V, respectively. More importantly, they demonstrate excellent stability in air for more than two months, while those based on CsPbI3 can survive only a few days in air. The progress reported represents a major leap for all-inorganic PSCs and paves the way for their further exploration in order to achieve higher performance.