Multi-Objective Optimization of CIGS Solar Cells Using Coupled Electro-Optical Simulation and Defect Engineering
Year: 2026
Type: article
Abstract: This study presents a comprehensive optimization framework for Cu(In,Ga)Se2 (CIGS) solar cells by integrating coupled electro-optical simulation with defect engineering. Using Silvaco Atlas and SCAPS-1D, the work systematically investigates the combined effects of absorber thickness, acceptor doping, buffer-layer selection, bulk defect density, and back-surface-field (BSF) grading on device performance. The main novelty lies in the simultaneous optimization of bulk, interfacial, and transport-related parameters through a multi-objective approach, enabling the identification of strong synergistic effects that are not captured by single-parameter tuning. The optimized device, featuring a 2.1 μ absorber, Zn(O,S) buffer layer, 42 nm buffer thickness, and a graded BSF with 320 nm depth and maximum Ga fraction of 0.52, achieves a power conversion efficiency of 21.65%, representing a 1.45 percentage-point improvement over the baseline structure. The Zn(O,S) buffer exhibits the lowest interface recombination velocity of 850 cm/s, compared with 3800 cm/s for ZnS, while BSF grading reduces back-surface recombination velocity from about 1500 cm/s to 420 cm/s. Sensitivity analysis further shows that bulk defect density is the most influential parameter, with a normalized sensitivity of 0.82, followed by buffer conduction-band offset, BSF strength, and absorber doping. These results highlight the critical role of defect and interface control in unlocking higher CIGS device performance and provide a practical optimization route for next-generation thin-film solar cells.
Institution: Islamic Azad University Saveh
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7225009347