Constructing A Carrier Collection Framework at The Rear Interface in Cu₂ZnSn(S, Se)₄ Solar Cells by Selenizing an...

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Copper Zinc Tin Sulfide Selenide (CZTSSe) is a promising material for low-cost, efficient photovoltaic devices.
• Improving the performance of CZTSSe solar cells often involves optimizing the absorber layer and the back contact interface.
• Defects and poor carrier transport at the rear interface can limit the overall efficiency of CZTSSe solar cells.

Purpose of the Study:

• To investigate the effect of an ultrathin CuBi2O4 (CBO) nanolayer on the performance of CZTSSe photovoltaic cells.
• To understand how the CBO layer influences the CZTSSe absorber formation and the properties of the rear interface.
• To enhance the overall power conversion efficiency of CZTSSe solar cells through interface engineering.

Main Methods:

• Fabrication of CZTSSe photovoltaic devices with an ultrathin CBO nanolayer inserted between the Mo back contact and the CZTSSe absorber.
• High-temperature annealing to induce CBO layer decomposition and formation of beneficial secondary phases.
• Characterization of the CZTSSe absorber layer morphology, grain size, and composition.
• Analysis of the electrical properties and carrier transport mechanisms at the rear interface.

Main Results:

• The CBO nanolayer promoted the formation of a more compact CZTSSe absorber layer with larger grain sizes.
• Decomposition of the CBO layer during annealing resulted in the formation of Cu-doped bismuth selenide at the rear interface.
• The Cu-doped bismuth selenide layer improved carrier transport and enhanced electrical properties at the CZTSSe rear interface.
• Significant improvements were observed in key photovoltaic parameters, leading to higher overall solar cell efficiency.

Conclusions:

• The ultrathin CBO nanolayer serves as an effective interfacial layer for enhancing CZTSSe solar cell performance.
• The CBO layer facilitates improved absorber quality and beneficial modifications at the rear contact.
• This approach offers a viable strategy for boosting the efficiency of CZTSSe-based photovoltaic devices.