Prototypical MAPbI3: The role of its three components in high-performance solar cells

For over a decade, methylammonium lead triiodide (MAPbI 3 ) has served as the foundational model for perovskite solar cells, driving unprecedented advances in power conversion efficiency and providing critical insights into the optoelectronic properties of halide perovskites. However, the emergence of more stable and efficient mixed compositions has raised a pivotal question: is MAPbI 3 nearing obsolescence in scientific research and practical applications? This review critically examines the historical role and enduring scientific value of MAPbI 3 , and also discusses its fundamental limitations, including thermal and moisture instability. After contrasting its properties with those of advanced mixed-perovskite systems, we sum up that MAPbI 3 is still scientifically important as a prototypical material for fundamental studies. Including crystallization kinetics, structural distortion, defect chemistry, charge carrier dynamics, ion migration, phase stability, degradation mechanisms, and so on, even if it is not the best for commercial devices. Thus, while MAPbI 3 -based devices may indeed be exiting the commercial stage, its legacy continues to shape the development of next-generation perovskite photovoltaics.