Fabricating High-Efficiency Sb₂(S,Se)₃ Solar Cells by Novel Additive-Assisted Longitudinal Component Engineering

Area of Science:

• Materials Science
• Renewable Energy
• Thin Film Technology

Background:

• Antimony selenosulfide (Sb2(S,Se)3) solar cells show promise, with efficiencies exceeding 10.0%.
• The hydrothermal synthesis method for Sb2(S,Se)3 thin films presents challenges in achieving high quality due to uncontrollable reaction kinetics.
• This uncontrollability acts as a bottleneck for the development of efficient Sb2(S,Se)3 solar cells.

Purpose of the Study:

• To address the limitations of the hydrothermal process in Sb2(S,Se)3 thin film fabrication.
• To investigate the use of triethanolamine (TEA) as an additive to regulate the reaction kinetics.
• To optimize the properties of Sb2(S,Se)3 thin films for improved solar cell performance.

Main Methods:

• Utilizing triethanolamine (TEA) as a chelator to control the reaction kinetic process during Sb2(S,Se)3 thin film formation.
• Analyzing the impact of TEA on elemental distribution (Se/(S+Se)), bandgap, crystal orientation, and defect passivation.
• Investigating the formation of a back surface gradient in the Sb2(S,Se)3 thin film.

Main Results:

• TEA enables time-domain control of the reaction, optimizing Se/(S+Se) distribution and reducing bandgap offset.
• Enhanced (021) and (061) crystal orientations and passivation of harmful VSe1 defects were observed.
• A uniform back surface gradient reduced minority carrier recombination, increasing photocurrent and decreasing diode current.
• Significant improvements in short-circuit current density (Jsc) by 8.6% and fill factor (FF) by 5.5% were achieved.
• The open-circuit voltage deficit was reduced by 44 mV.

Conclusions:

• Triethanolamine effectively regulates the hydrothermal synthesis of Sb2(S,Se)3 thin films.
• The optimized films exhibit improved structural and electronic properties, leading to enhanced solar cell performance.
• This approach yields a record efficiency of 9.94% for Sb2(S,Se)3 solar cells synthesized using sodium selenosulfate, overcoming previous limitations.