Direct correlation between open-circuit voltage and quasi-fermi level splitting in perovskite solar cells: a computational step involving thickness, doping, lifetime, and temperature variations for green solutions

Abstract

In this study, a 1D perovskite-based solar cell was simulated using COMSOL, incorporating CH₃NH₃GeI₃ (organic in-organic hybrid) as an absorber layer, SnO₂ as the electron transport layer (ETL), and Cu₂Te as the hole transport layer (HTL). The simulations reveal that reducing the ETL's thickness enhances current density (J), although the maximum output power (P_max) diminishes with ETL's thickness. Conversely, increasing the absorber layer's thickness boosts open-circuit voltage (V_oc) and efficiency, exhibiting direct relation between V_oc and quasi-Fermi level splitting. Furthermore, variations in HTL thickness do not significantly affect V_oc or P_max. Notably, V_oc and P_max both increase with acceptor density, conversely, increase in donor density leads to declines in both V_oc and P_max. While extending the electron–hole (e–h) lifetime within the ETL results in marginal efficiency improvements, significant enhancements in the e–h lifetime within the absorber layer substantially improve performance. However, the efficiency remains unaffected by variations in the e–h lifetime of the HTL. Additionally, higher operating temperatures adversely impact device performance, reducing J, V_oc, P_max, fill factor, and overall efficiency. This study provides critical insights into optimizing material properties and device parameters for experimental applications, underscoring the potential of CH₃NH₃GeI₃-based perovskites as viable candidates for next-generation photovoltaic technologies.