Mathematical Approach to Photonic Analysis of Ag-Doped HfO₂ for Antireflective and Intermediate Reflective Applications in Planar a-Si Solar Cells

This work presents a novel dual-function optical layer composed of silver-doped hafnium dioxide (Ag:HfO₂), engineered to serve simultaneously as an antireflective coating (ARC) and an intermediate reflective layer (IRL) in planar amorphous silicon (a-Si) solar cells. Scilab-based simulations employing the Transfer Matrix Method (TMM) are utilized to analyze the optical behavior of the Ag:HfO₂ layer, allowing for precise modeling of light propagation and interference within multilayer structures. The incorporation of silver into HfO₂ modifies its permittivity through free carrier effects governed by the Drude model, enabling epsilon-near-zero (ENZ) conditions and negative permittivity regimes. These optical characteristics enhance light trapping and absorption by providing efficient antireflection at the front surface and improved internal reflection at the rear interface.The suggested method significantly improves optical performance, including enhanced absorption and internal quantum efficiency (IQE), without the need of complicated nanostructures. This material-engineered, planar technique provides a scalable and fabrication-compatible approach to improving the efficiency of next-generation thin-film solar cells