Exploring WS2 as a Potential Buffer Layer for Improved CFTS-Solar Cell Performance

This study explores the photovoltaic performance of CFTS non-toxic p-type solar cell absorber using WS₂ TMDCs as an innovative buffer layer. The SCAPS-1D software is used to investigate the potentiality of WS2 as buffer material in CFTS solar cells. We analyze various electrical specifications such as short circuit current (Jsc), open circuit voltage (Voc), the fill factor (FF), and power conversion efficiency (PCE). The device has been studied by varying thickness, doping concentration, carrier mobility, and defect density of each layer. The results achieve at room temperature a PCE of 36.25%, with Voc at 1.165 V, Jsc at 34.814 mA/cm², and FF at 89.16% for a 1 μm CFTS absorber. The significant improvement in PCE is primarily attributed to the enhanced Jsc, resulting from the WS₂ layer's ability to absorb sub-bandgap photons. The study also highlights the detrimental impact of deep defect levels on PCE and Jsc, emphasizing the potential of WS2 as a high-performance buffer layer. Finally, the effects of operating temperature on cell performance within the range of 300 to 500 K are analyzed and addressed. Notably, the observed decline in the Voc is most likely attributed to the increase in the saturation current, suggesting an interplay between temperature and cell behavior. The findings indicate that CFTS paired with a WS₂ buffer layer is a promising alternative to conventional thin-film photovoltaic materials.