Comprehensive assessment of all-inorganic CsPbI3–xBrx perovskite-based solar cells: Interface engineering, stability, and economic aspects

All-inorganic perovskite materials based on CsPbI3–xBrx (x = 0, 1, 2, and 3) have garnered considerable attention from the photovoltaic (PV) community on account of their superior resistance to moisture and temperature in comparison to organic–inorganic hybrid (OIH)-perovskite solar cells (PSCs). Since the initial report in 2015, extensive research and ongoing preparation process optimization have led to a substantial improvement in the power conversion efficiency (PCE) of CsPbI3–xBrx PSCs, from 2.9 % to over 21.5 %. Nevertheless, the device PCE of PSCs based on CsPbI3–xBrx remains inferior to that of OIH-PSCs. As a result, significant efforts are being made to increase the overall PCE of CsPbI3–xBrx PSCs through the synergistic optimization of the perovskite layer and device interfaces. In this review, a comprehensive discussion is made on the stability of the material against thermal and high moisture environments, followed by a thorough analysis of the methodologies for fabricating pinhole-free and uniform CsPbI3–xBrx films. The recent development of all-inorganic CsPbI3–xBrx PSCs based on interface engineering is overviewed, followed by a detailed discussion on the commercial viability of the CsPbI3–xBrx PSCs. Finally, some suggestions on overcoming development bottlenecks are presented to obtain an understanding of CsPbI3–xBrx PSCs and encourage future research opportunities.