Light capture efficiency of subwavelength cylindrical grating-enhanced MAPbI₃ perovskite devices based on EMT design

High-efficiency perovskite devices achieve nearly 100% internal quantum efficiency (IQE) by absorbing all incident light, making it challenging to further enhance performance through conventional optimization methods. Therefore, surface electrode patterning can be employed to increase incident light penetration into the device, thereby improving its optoelectronic performance. This study employs equivalent theoretical media and diffraction principles to design subwavelength cylindrical gratings on fluorine-doped tin oxide (FTO) surfaces, achieving full transmission at fixed wavelengths. Furthermore, a three-dimensional finite element method model analyzes the optical and electrical characteristics of perovskite solar cells, thereby validating the reliability of the theoretical structure. Simulation results indicate that C_400-700 achieves nearly one transmittance at the specified wavelengths. The optimal C₅₀₀ structure increases photogenerated carrier concentration by 12.2%, yields a short-circuit current of 24mA/cm² (compared to 21.3mA/cm² for the planar structure), and boosts the photovoltaic conversion efficiency (PCE) by 2.1%. This study provides a novel, to the best of our knowledge, approach for enhancing the photovoltaic conversion efficiency of MAPbI₃-based perovskite solar cells.