Biomimetic Multilayer Dielectric Nanostructures for Enhanced Light Absorption in Thin-Film Photovoltaic Cells: Design, Fabrication, and Optical Characterization

Abstract

Light management is a critical challenge in thin-film solar cells due to the inherent trade-off between optical absorption and carrier collection efficiency. Conventional anti-reflection coatings offer limited bandwidth and angular performance. Inspired by the brilliant structural coloration of Morpho butterfly wings, this study presents the design, fabrication, and characterization of biomimetic multilayer dielectric nanostructures for broadband light absorption enhancement in thin-film silicon solar cells. We designed and optimized periodic multilayer stacks of titanium dioxide (TiO₂) and silicon dioxide (SiO₂) using the finite-difference time-domain (FDTD) method. The optimized structures, with 11 and 15 layers, were fabricated on silicon substrates using a combination of electron-beam lithography and reactive-ion etching. Optical characterization revealed a significant reduction in reflectance to below 5% across a broad spectral range (400-900 nm) and a wide range of incident angles (0-60°). When integrated into thin-film silicon solar cells, the 15-layer biomimetic structure led to a remarkable 42.3% enhancement in the short-circuit current density (Jsc) and a 58.7% improvement in power conversion efficiency (PCE) from 5.93% to 9.41% compared to the flat reference cell. This work demonstrates a powerful, cross-disciplinary approach, translating a biological light-manipulation strategy into a highly effective solution for photovoltaic applications, and opens new avenues for designing advanced light-trapping schemes in next-generation solar energy systems.