Improved Photovoltaic Performance of CsPbI2Br Perovskite Films via Bivalent Metal Chloride Doping

Cesium-based all-inorganic perovskite absorbers have attracted increasing attention due to their superior thermal stability, compared to their organic–inorganic counterparts. Up to now, it is a challenge to fabricate high-efficiency all-inorganic perovskite solar cells (PSCs) with low defect densities. Herein, we used bivalent metal chloride salts (SrCl 2 and NiCl 2 ) to optimize CsPbI 2 Br films. The experimental results indicate that this method could deliver high-quality films with improved electronic property. As a result, the champion device based on the 0.01 M SrCl 2 –doped CsPbI 2 Br film achieved a power conversion efficiency (PCE) of 16.07% with a high open voltage ( V OC ) of 1,322 mV, which is about 18% higher than that of the pristine device.