Fully-inorganic strontium incorporated CsPbI2Br perovskite solar cells with promoted efficiency and stability

Abstract In the present investigation, we fabricated strontium (Sr2+) incorporated CsPbI2Br-based inorganic perovskite solar cells in ambient conditions. The morphology, crystallinity, absorption, elemental composition and photoluminescence analysis of the bare CsPbI2Br and CsPb1-xSrxI2Br perovskite thin films were studied systematically to investigate the role of Sr2+ incorporation. It is observed that the surface morphology of the CsPbI2Br perovskite thin film has been improved by partial substitution of Pb2+ by Sr2+ which facilitates photoactive black phase-stabilization and defect passivation. The champion device having CsPb0.98Sr0.02I2Br composition exhibited a power conversion efficiency (PCE) of 16.61 % which is much higher than the bare device (13.65 %). Furthermore, our CsPb0.98Sr0.02I2Br-based devices maintain > 85 % of its initial efficiency over 100 h in ambient conditions.