Design and numerical investigation of cadmium telluride (CdTe) and iron silicide (FeSi2) based double absorber solar cells to enhance power conversion efficiency

Inorganic CdTe and FeSi2-based solar cells have recently drawn a lot of attention because they offer superior thermal stability and good optoelectronic properties compared to conventional solar cells. In this work, a unique alternative technique is presented by using FeSi2 as a secondary absorber layer and In2S3 as the window layer for improving photovoltaic performance parameters. Simulating on SCAPS-1D, the proposed double-absorber (Cu/FTO/In2S3/CdTe/FeSi2/Ni) structure is thoroughly examined and analyzed. The window layer thickness, absorber layer thickness, acceptor density (NA), donor density (ND), defect density (Nt), series resistance (RS), and shunt resistance (Rsh) were simulated in detail for optimization of the above configuration to improve the PV performance. According to this study, 0.5 µm is the optimized thickness for both the CdTe and FeSi2 absorber layers in order to maximize the efficiency (η). Here, the value of the optimum window layer thickness is 50 nm. For using CdTe as a single absorber, η is achieved by 13.26%. However, for using CdTe and FeSi2 as a dual absorber, η is enhanced and the obtaining value is 27.35%. The other parameters are also improved and the resultant value for the fill factor is 83.68%, the open-circuit voltage (Voc) is 0.6566 V, and the short circuit current density (Jsc) is 49.78 mA/cm2. Furthermore, the proposed model performs well at 300 K operating temperature. The addition of the FeSi2 layer to the cell structure has resulted in a significant quantum efficiency enhancement because of the rise in solar spectrum absorption at longer wavelengths (λ). The findings of this work offer a promising approach for producing high-performance and reasonably priced CdTe-based solar cells.