High-Performance All-Inorganic Cesium Halide Perovskite Solar Cells

All-inorganic perovskites have gained significant attention in recent years due to their superior thermal and environmental stability compared to their organic-inorganic hybrid counterparts. These materials, typically represented by CsPbX₃, exhibit excellent optoelectronic properties such as high absorption coefficients, suitable bandgaps, and long carrier diffusion lengths, making them promising candidates for next-generation photovoltaic applications. This review provides a comprehensive overview of the structural characteristics, phase behavior, and optoelectronic properties of inorganic perovskites. Various fabrication techniques, including solution processing, vacuum deposition, and hybrid approaches, are discussed with respect to their influence on film quality and device performance. Key issues, including phase instability and defect formation, are discussed, together with recent advances in composition engineering, additive optimization, and interfacial modification. In addition, the environmental and health concerns associated with lead usage have driven the development of lead-free alternatives, such as bismuth-, tin-, or antimony-based perovskites. This review also summarizes progress in the fabrication of large-area and flexible IPSCs and explores their potential applications under extreme environmental conditions. Finally, the remaining challenges and future opportunities for advancing high-performance all-inorganic perovskite photovoltaics are highlighted.