Performance analysis of tungsten disulfide (WS₂) as HTL for MoS₂ solar cell with ZnSe ETL and graphene as window layer

In this study, a novel MoS₂-based solar cell structure, Al/Gr/ZnSe/MoS₂/WS₂/Ni, is analysed and optimised. Various parameters were carefully adjusted employing SCAPS-1D software. Through numerical analysis and investigations, optimal values were identified for key parameters, including a 1.0 μm thick MoS₂ absorption layer with a doping density of 10¹⁶ cm⁻³, a 0.05 μm thick WS₂ HTL with a doping density of 10¹⁹ cm⁻³, and a 0.02 μm thick ZnSe ETL with a doping density of 10¹⁷ cm⁻³. Simulation results revealed that the proposed structure, incorporating the WS₂ HTL, achieved an impressive efficiency of 28.37%, surpassing the efficiency of the structure without the HTL (21.79%). This highlights the significant role of WS₂ in reducing recombination rates at the back surface of the solar cell, leading to improved overall efficiency. Furthermore, investigating the effect of density and electron capture cross-section of bulk defects within the \({\text{MoS}}_{2}\) ${\text{MoS}}_2$ layer underscores the critical importance of reducing the adverse impact of these defects to achieve high-efficiency \(Mo{S}_{2}\) $Mo{S}_2$ TFSCs. Our findings reveal the potential for MoS₂ TFSCs to achieve a remarkable PCE of 32.61%. The nearly zero lattice mismatch between MoS₂ and the WS₂ HTL suggests its suitability for fabricating high-quality TFSCs, minimizing both interface and bulk defects. This further advances the development of cost-effective and high-performance MoS₂-based TFSCs.