A comprehensive photovoltaic study on tungsten disulfide (WS2) buffer layer based CdTe solar cell

Area of Science:

• Materials Science
• Photovoltaics
• Thin-film Solar Cells

Background:

• Transition metal di-chalcogenides like Tungsten disulfide (WS₂) possess excellent optoelectronic properties.
• WS₂ is a non-toxic, earth-abundant material with potential for solar cell applications.
• Traditional Cadmium Sulfide (CdS) buffer layers in Cadmium Telluride (CdTe) solar cells raise environmental concerns.

Purpose of the Study:

• To investigate the potential of WS₂ as an eco-friendly buffer layer in CdTe thin-film solar cells.
• To numerically compare the performance of a SnO₂/WS₂/CdTe/Au solar cell with a baseline ITO/ZnO/CdS/CdTe/Au structure.
• To analyze the impact of various parameters on solar cell performance.

Main Methods:

• Numerical simulation using the SCAPS-1D solar simulator.
• Comparative analysis of proposed (SnO₂/WS₂/CdTe/Au) and baseline (ITO/ZnO/CdS/CdTe/Au) solar cell structures.
• Investigation of parameters including carrier generation rate, spectral response, I-V characteristics, defect densities, operating temperature, and C-V characteristics.

Main Results:

• The proposed SnO₂/WS₂/CdTe/Au solar cell achieved a conversion efficiency of 20.55%.
• Defect tolerance levels were determined: 10¹⁷ cm⁻³ for WS₂ bulk and 10¹² cm⁻³ for the WS₂/CdTe interface.
• The study identified poor structural robustness and thermal stability in the proposed cell design.

Conclusions:

• Tungsten disulfide (WS₂) shows promise as a viable, environmentally friendly, and cost-effective buffer material for CdTe thin-film solar cells.
• Further research is needed to address the thermal stability limitations of WS₂ in solar cell devices.
• The findings provide insights for fabricating improved CdTe thin-film solar cells.