Zinc ion functional doping for all-inorganic planar CsPbIBr2 perovskite solar cells with efficiency over 10.5%

Abstract

The all-inorganic CsPbIBr₂ perovskite solar cell (PSC) has received tremendous attention due to its favorable photoelectric properties and superior stability against moisture and heat attack. Nevertheless, the reported power conversion efficiency (PCE) of CsPbIBr₂ PSC is still far from its counterparts, mainly because of the inferior film crystallization and morphology of the CsPbIBr₂ light-absorbing layer, along with much trap defects and severe charge recombination. Herein, all-inorganic perovskite CsPbIBr₂ is doped with ZnBr₂ to improve crystallinity and morphology, optimize energy level alignment and enhance photovoltaic performance of PSC. Consequently, with the optimized concentration of Zn²⁺ (1%, at.), CsPb_0.99Zn_0.01IBr₂-based PSC shows the highest PCE of 10.51%, which is 34% higher than that of CsPbIBr₂-based PSCs (7.84%). Furthermore, the unencapsulated CsPb_0.99Zn_0.01IBr₂-based device exhibits superior long-term stability in ambient atmosphere and against heat. This study provides a feasible strategy for preparing a high quality perovskite film and improving the photovoltaic performance and long-term stability of CsPbIBr₂ PSCs, aiming at promoting the potential applications of CsPbIBr₂-based PSCs.