Optimization of Light‐Management Strategies in All‐Perovskite Four‐Terminal Tandem Solar Cells: Efficiency Enhancement and Optical Loss Analysis

ABSTRACT All‐perovskite four‐terminal tandem solar cells offer a promising platform for high‐efficiency photovoltaics due to their electrical independence and flexible subcell optimization. However, optical losses such as interfacial reflection and parasitic absorption limit device performance. In this study, a systematic light‐management optimization framework was established, and multiphysics simulations were employed to reveal how perovskite layer thickness, intermediate light‐coupling layer (ILCL) materials and thickness, and top cell structural inversion collaboratively regulate light distribution, electromagnetic field phase, and transmission and reflection characteristics. Optimizing the perovskite layer thickness balances light absorption between subcells, increasing the power conversion efficiency (PCE) from 25.0% to 26.1%. Further introduction of the ILCL with phase‐control design enhances optical coupling, raising the PCE to 28.10%. Numerical simulations indicate that top cell structural inversion effectively suppresses long‐wavelength reflection and enhances bottom cell absorption, resulting in a simulated PCE of 33.73%, approaching the theoretical limit predicted by a semiempirical model guided by experimental data. Quantitative analysis based on admittance and phase matching elucidates the optical mechanisms, providing generalizable guidance for the design of multijunction photovoltaic devices. These results demonstrate that a unified light‐management strategy not only systematically enhances device performance but also provides deep insights into the optical physics of all‐perovskite tandem solar cells.