Design and Optimization of High‐Efficiency Se _{1‐ x} Te _x

ABSTRACT

Selenium‐tellurium (Se _{1‐ x} Te _x ) alloys offer promising potential for thin‐film photovoltaics owing to their tunable bandgap, low cost, and environmental sustainability. By tuning the Se:Te ratio, the bandgap of Se _{1‐ x} Te _x alloys can be adjusted to an optimal value (≈1.35 eV) which is crucial for approaching the maximum efficiency of a single‐junction solar cell. Which enhances solar absorption and increases power conversion efficiency (PCE). In this simulation‐based work, we provide a comprehensive study to design Se _{1‐ x} Te _x ‐based TFSCs using SCAPS‐1D simulations. The optimization process involves key factors such as absorber layer thickness, defect densities, electron and hole transportation layers (ETLs and HTLs), and back contact work functions. The results indicate that Se _0.75 Te _0.25 solar cells achieve a significant improvement in PCE with optimized device architecture. Specifically, cells incorporating MoO _x as an HTL demonstrate a PCE of 21.94%. Interestingly, the HTL‐free cells, optimized for back contact work function, accomplished a comparable PCE of 21.59%, highlighting the feasibility of eliminating the HTL layer without compromising efficiency. To validate our approach, a global optimization of the HTL‐free structure was performed using a single‐objective genetic algorithm. The findings suggest that optimizing back contact material, defect density, and absorber thickness can lead to high‐efficiency Se _0.75 Te _0.25 ‐based TFSCs for terrestrial applications.