Defect Suppression Strategy Targeting Oxygen-Related States in Sb₂(S,Se)₃ Thin-Film Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Antimony chalcogenide Sb₂(S,Se)₃ is a promising material for eco-friendly thin-film solar cells due to its earth-abundant nature and favorable optoelectronic properties.
• Device performance in Sb₂(S,Se)₃ photovoltaics is highly dependent on the defect density and crystalline quality of the absorber layer.

Purpose of the Study:

• To investigate the influence of the post-annealing environment on the structural evolution and defect formation in Sb₂(S,Se)₃ films.
• To establish a method for producing high-quality Sb₂(S,Se)₃ absorber layers for enhanced photovoltaic device performance.

Main Methods:

• Comparative analysis of Sb₂(S,Se)₃ films annealed under different post-annealing environments (nitrogen vs. low vacuum).
• Characterization of film structure, crystallite orientation, defect density, and oxygen-related states.
• Fabrication and performance evaluation of thin-film photovoltaic devices using the treated absorber layers.

Main Results:

• Annealing in nitrogen effectively suppresses oxidation, leading to dense, well-oriented Sb₂(S,Se)₃ crystallites with reduced defects.
• Low-vacuum annealing promotes partial oxidation and void formation, negatively impacting charge transport.
• The best device with nitrogen-treated absorbers achieved a power conversion efficiency of 8.84% due to enhanced carrier collection and reduced interfacial recombination.

Conclusions:

• The post-annealing environment is crucial for controlling the crystallization mechanism and defect landscape in Sb₂(S,Se)₃ films.
• Nitrogen annealing provides a viable route for fabricating high-quality Sb₂(S,Se)₃ absorber layers for sustainable photovoltaic technologies.
• Optimized processing conditions are key to unlocking the full potential of antimony chalcogenides in next-generation solar cells.