Engineering inorganic perovskite solar cells: overcoming efficiency and stability barriers for next-generation photovoltaics

Inorganic perovskite solar cells (IPSCs) offer superior thermal stability and reduced toxicity compared with hybrid perovskites, yet their practical deployment is still restricted by phase instability, interfacial degradation, and limited power conversion efficiency (PCE) under operational conditions. This review systematically outlines and connects strategies for advancing cesium lead halide (CsPbX₃) systems, emphasizing three complementary directions to build a coherent narrative accessible to both experts and new readers. First, compositional tuning through halide alloying, cation substitution, and controlled doping has been shown to stabilize the black perovskite phase and suppress defect formation. Second, interfacial engineering, including surface passivation, additive-assisted nucleation, and protective layers, has emerged as a key approach to reduce non-radiative recombination and improve environmental resilience. Third, scalable fabrication routes such as solution processing, vapor deposition, and nanostructured templating are assessed for their impact on crystallinity, film uniformity, and large-area device integration. Looking ahead, future research must prioritize lead-free alternatives, low-temperature processing compatible with flexible substrates, and predictive modeling for interface optimization. By consolidating cross-disciplinary insights, this review provides a coherent roadmap to accelerate the translation of IPSCs from laboratory studies to practical, sustainable photovoltaic technologies.