An Optimization Path for Sb₂(S,Se)₃ Solar Cells to Achieve an Efficiency Exceeding 20

Area of Science:

• Materials Science
• Solid-State Physics
• Renewable Energy

Background:

• Antimony selenosulfide (Sb₂(S,Se)₃) is an eco-friendly semiconductor for thin-film photovoltaics.
• Current Sb₂(S,Se)₃ solar cells achieve 10.75% power conversion efficiency (PCE), hindered by open-circuit voltage (V_oc) and fill factor (FF) losses.
• Understanding the relationship between V_oc, FF, and internal resistance is crucial for efficiency improvements.

Purpose of the Study:

• To investigate the theoretical link between V_oc and FF in Sb₂(S,Se)₃ solar cells.
• To develop and implement a phased optimization strategy to overcome V_oc and FF losses.
• To achieve PCEs exceeding 20% for Sb₂(S,Se)₃-based thin-film photovoltaics.

Main Methods:

• Theoretical analysis of V_oc and FF dependencies on internal resistance and non-radiative recombination.
• Phased optimization including internal resistance reduction, band level modification, interface recombination minimization, and absorber layer thickening.
• Fabrication and characterization of Sb₂(S,Se)₃ thin-film solar cells.

Main Results:

• Optimizing internal resistance reduced FF loss from 10.79% to 2.80%, boosting PCE to 12.57%.
• Modifying band levels increased V_oc by 18.75%, achieving PCE over 15%.
• Minimizing interface recombination and increasing absorber thickness to 600 nm resulted in a record PCE of 26.77%.

Conclusions:

• Internal resistance significantly impacts FF in low V_oc/FF conditions, more than non-radiative recombination.
• A systematic optimization approach addressing internal resistance, band alignment, interface recombination, and absorber thickness is effective.
• This study provides a roadmap for developing high-efficiency Sb₂(S,Se)₃ solar cells, surpassing 20% PCE and reaching 26.77%.