Design-driven efficiency enhancement of CdTe1−xSex solar cells via interface band alignment and optimization

This study develops a comprehensive optical–electrical model to identify the efficiency-limiting mechanisms in CdTe1−xSex solar cells. The aim is to provide a unified understanding of how various recombination pathways, tunneling-enhanced, Auger, Shockley–Read–Hall (SRH), interface, and non-radiative recombination, collectively impact device performance. While prior research typically focuses on isolated mechanisms, our integrated approach reveals their combined influence on efficiency losses. The model shows strong agreement with experimental data and serves as a fitness function for a multi-objective genetic algorithm (MOGA), enabling systematic optimization of device parameters. Our results identify Ga2O3 as a promising Cd-free ETL, achieving an optimized efficiency of 25.8%, with JSC = 24.93 mA/cm2, VOC = 1.27 V, and FF = 80.28%. These findings offer valuable insights into degradation mechanisms and provide a pathway for designing high-performance, environmentally friendly CdTe1-xSex solar cells.