Engineering of Heterogeneous Redox Environment Enables Balanced Phase Evolution and Nucleation for 14.4% Efficiency...

Area of Science:

• Materials Science
• Renewable Energy
• Semiconductor Physics

Background:

• Copper zinc tin sulfide selenide (CZTSSe) solar cells face challenges like multilayer structures and high defect density.
• These issues stem from rapid grain growth and high-temperature decomposition during fabrication.

Purpose of the Study:

• To enhance crystal quality and suppress defect formation in CZTSSe absorbers.
• To improve the power conversion efficiency of CZTSSe solar cells.

Main Methods:

• Manipulating the heterogeneous redox environment in the CZTS precursor by inserting Cu²⁺/Sn²⁺ layers into a Cu⁺/Sn⁴⁺ precursor.
• Balancing crystallization and phase evolution during absorber growth.

Main Results:

• Achieved a monolayer large-grain structure in the CZTSSe absorber.
• Reduced defect density by an order of magnitude.
• Attained a power conversion efficiency of 14.4%.

Conclusions:

• The proposed strategy effectively promotes crystal quality and suppresses defects in CZTSSe solar cells.
• Manipulating the precursor's redox environment is key to improving CZTSSe absorber performance.
• This advancement offers a promising pathway for more efficient and stable CZTSSe solar cells.