Predicting the Inverse Coupling Between Temperature and Photovoltaic Output Power in Perovskite Heterojunction Solar Cells

There is an urgent need for effective renewable energy technology due to the growing global energy demand. Solar energy is a clean and plentiful answer among them, and perovskite solar cells are becoming more and more popular because of their remarkable photovoltaic (PV) capabilities and affordability. This work presents a novel double‐absorber solar cell configuration based on 1D TiO 2 /CsSnI 3 /BiFeO 3 (BFO)/Spiro‐OMeTAD, investigated through comprehensive simulation using COMSOL Multiphysics. The dual absorber layers are designed to improve light absorption and charge carrier separation, aiming to boost overall device performance. Simulation results reveal that the short‐circuit current density ( J sc ) reaches a maximum of 33.05 mA/cm 2 and peak power conversion efficiency (PCE) of 18.11% achieved at a hole transport layer (HTL) thickness of 205 nm. Furthermore, maximum output power ( P max ) reduces from 17.11 to 11.16 mW/cm 2 , as the temperature rises, disclosing the inverse coupling between power and temperature. The open‐circuit voltage ( V oc ) peaks at 0.93 V, and the fill factor (FF) attains 82.36% at an absorber layer thickness of 10 nm. These findings demonstrate the promising potential of the proposed lead (Pb 2+ )‐free structure, with future work focusing on experimental validation and stability enhancement for practical applications.