Integrated simulation and machine learning framework for high-performance lead-free RbGeI3 perovskite solar cells with WS2/CuI transport layers
摘要
The present work comprehensively investigates the design, optimization, and predictive modeling of a high-performance, lead-free RbGeI3-based perovskite solar cell employing WS₂ as the ETL and CuI as the HTL. Numerical simulations performed using SCAPS-1D were validated against theoretical efficiency limits and electrostatic consistency checks, confirming the model’s physical reliability. The device achieved an optimized η of 24.15%, with Voc = 1.1184 V, Jsc = 25.999 mA·cm−2, and FF = 83.09%, demonstrating excellent charge extraction and minimal recombination losses. Systematic parametric analyses revealed the critical influence of absorber doping, transport layer defect density, resistive losses (Rs/Rsh), absorber thickness (t-Abs), defect density (Nt), temperature, and solar irradiance on overall performance. Optimal operation was achieved for Nt = 1014 cm⁻3, where light absorption and carrier transport are well balanced. Furthermore, machine learning (ML) algorithms, including XGBoost, random forest, and gradient boosting, were employed to predict photovoltaic outputs with near-perfect accuracy (R2 ≈ 1.0). The XGBoost model successfully identified absorber defect density, series resistance, and illumination intensity as the most dominant performance-determining features. The results demonstrate that the synergistic combination of WS2/CuI transport layers and ML-guided optimization establishes a promising framework for stable, efficient, and eco-friendly RbGeI3-based PSCs, paving the way for next-generation lead-free photovoltaic technologies.