Perovskite semiconductors for solar-driven photoelectrocatalytic applications: Materials, mechanism, and perspectives

Perovskite semiconductors (ABX 3 ) are increasingly being investigated as photoelectrocatalytic (PEC) materials for solar-to-chemical conversion owing to their favorable optoelectronic properties and strong light-harvesting capability. Their tunable bandgaps, pronounced visible-light absorption, and efficient charge-carrier transport make these materials attractive for diverse PEC applications. This review examines key aspects of material and structural design, including zero-dimensional (0D) to three-dimensional (3D) perovskite architectures and physical and chemical fabrication techniques. In contrast to earlier reviews that focused mainly on individual PEC reactions or particular perovskite families, the present review critically compares oxide, oxynitride, Pb-based halide, and Pb-free perovskite-derived materials and correlates dimensionality, defect chemistry, charge-transfer mechanisms, catalytic performance, and stability. Heterojunction engineering, defect modulation, interface passivation, and device integration are further assessed to identify the principal factors governing PEC efficiency, selectivity, stability, and practical implementation. Finally, future directions involving lead-substituted compositions, scalable fabrication, operando characterization, and commercially relevant PEC systems are discussed.