Material and Device Parameter Optimization for High-Efficiency Silicon, CdTe, CIGS, and Perovskite Solar Cells: A Comparative SCAPS-1D Simulation Study

Abstract

The simulation results provide a clear comparison of how the bandgap and material properties of different absorber layers influence the performance of solar cells. The analysis shows that the bandgap of an absorber plays a major role in determining the balance between the generated current and the achievable voltage. Materials with bandgaps in the range of about 1.3–1.5 eV are particularly attractive because they can make effective use of the incident solar spectrum while maintaining a relatively high output voltage. When recombination losses are kept low, such materials have the potential to deliver efficiencies close to the theoretical Shockley–Queisser limit. On the other hand, a large voltage deficit generally indicates significant recombination losses, which reduces the practical efficiency of the device. The thickness-dependent simulation of the perovskite absorber shows that the device achieves its best performance at an absorber thickness of approximately 400–500 nm, with a maximum power conversion efficiency of around 21%. Increasing the thickness beyond this range does not necessarily lead to a corresponding increase in efficiency, as additional material can also increase carrier recombination. Similarly, using an excessively thin absorber may reduce light absorption and consequently limit the short-circuit current density. Therefore, selecting an appropriate absorber thickness is important for obtaining a suitable balance between optical absorption and electrical losses. The influence of defect density is also significant. The simulation indicates that reducing the bulk defect concentration to below 1 × 10¹⁵ cm⁻³ produces a noticeable improvement in both the open-circuit voltage (VOC) and fill factor (FF). A lower concentration of defects reduces the number of recombination centers within the absorber, allowing a greater proportion of the photogenerated charge carriers to contribute to useful current. This highlights the importance of controlling material quality during the fabrication of high-performance photovoltaic devices. The bandgap comparison further indicates that absorbers with bandgaps close to approximately 1.34 eV, including CdTe and suitably designed perovskite materials, can achieve relatively high simulated efficiencies. Their favorable bandgap and lower recombination losses provide a better balance between voltage generation and current production. In comparison, materials suffering from larger voltage losses show a greater departure from their theoretical efficiency potential. An important outcome of the study is that perovskite absorbers can achieve high efficiency using comparatively thin active layers. This feature can reduce material requirements and supports the development of lightweight and potentially low-cost photovoltaic devices. Overall, the results demonstrate that careful control of bandgap, absorber thickness, and defect density is essential for improving solar-cell performance. The findings also provide useful guidance for future device optimization and the development of efficient photovoltaic technologies for sustainable energy generation.