Material–Property Considerations for Efficiency Limits in Perovskite Solar Cells

Perovskite solar cells (PSCs) have reached certified efficiencies above 27%, approaching practical performance limits for single‐junction devices. As further gains become increasingly difficult, attention is shifting from isolated process improvements toward understanding the material and device parameters that collectively determine photovoltaic performance. This review examines key quantities associated with recombination, charge transport, internal electric fields, and optical management, including surface recombination velocity, carrier diffusion coefficients, built‐in potential, optical absorption, absorber‐layer thickness, and excess carrier concentration. The mixed ionic–electronic character of metal‐halide perovskites is also considered, with emphasis on how ion migration and field screening influence the interpretation of electronic parameters and operational behavior. Reported experimental and modeled values are compared across different absorber compositions and device architectures, highlighting their dependence on interfaces, processing conditions, measurement protocols, and device state. Particular attention is given to recent strategies involving interface passivation, ultrathin absorbers, light management, compositional control, and ion‐migration suppression, together with the trade‐offs that may arise when these approaches are combined. By integrating experimentally accessible quantities and modeled material parameters within a device‐physics framework, this review establishes architecture‐dependent benchmarks and clarifies how coupled electronic, ionic, optical, and interfacial processes define practical efficiency limits in PSCs.