Numerical Study of Graded CZT (S, Se) Solar Cell with 2D Transition Metal Dichalcogenide Tungsten Disulfide (WS2) as a Buffer Layer

Recently, there has been a surge of research interest in exploring solar cells based on Cu2ZnSn(S, Se)4 (CZTSSe) for enhanced efficiencies. Traditionally, CdS has served as the buffer layer in these solar cells. However, there is growing scientific exploration aimed at replacing CdS with alternative materials. This work focuses on leveraging a graded CZTSSe absorber layer alongside tungsten disulfide (WS2) 2D transition metal dichalcogenides. WS2 semiconductor as buffer layer is less price, low toxicity with high‐stability, and its performance is compared to that of CdS/CZTSSe solar cells. This comparative study aims to assess the efficacy of the WS2/CZTSSe structure as a potential alternative to the conventional CdS/CZTSSe configuration, with the overarching objective of enhancing overall solar cell efficiency. Initially, to demonstrate the accuracy of our simulated results, a comparison is made between the reported experimental data of CdS/CZTSSe and the simulated data. This numerical investigation utilizes solar cell capacitance simulator ‐1D software. The primary focus of this research is to evaluate the effects of varying thicknesses and doping densities of the absorber and buffer layers, as well as WS2, CdS, and CZTSSe defect densities, on Voc, Jsc, fill factor (FF), and power conversion efficiency. The aim is to achieve optimal device performance through systematic optimization of these parameters. The findings reveal that the WS2/CZTSSe solar cell achieves the highest conversion efficiency of 14.38%, accompanied by a Voc of 0.6920 V, Jsc of 24.96 mA cm−2, and FF of 83.28%. This performance surpasses that of the CdS/CZTSSe configuration, which demonstrates an efficiency of 12.74%, Voc of 0.518 V, Jsc of 37.77 mA cm−2, and FF of 65.10%. These results hold significant promise for the practical implementation of WS2/CZTSSe solar cell structures, offering a pathway toward generating clean, pollution‐free, and cost‐effective energy solutions.