Transparent MATLAB-Based Optical–Electrical Modelling and Optimisation of a Monolithic Lead-Free Perovskite–Silicon Tandem Solar Cell

This study presents a transparent MATLAB-based optical–electrical modelling framework for the simulation and optimisation of monolithic lead-free perovskite–silicon tandem solar cells. Unlike conventional black-box simulation tools, the proposed framework provides full equation-level control over optical absorption, external quantum efficiency (EQE), carrier generation, current matching, and electrical transport, enabling reproducible and flexible device optimisation. The modelling approach was first validated against reported lead-free perovskite solar cell architectures, demonstrating good agreement with published benchmark results. Using the validated framework, a monolithic tandem architecture incorporating SnF2 defect passivation, a MoOx hole-extraction layer, an anti-reflection coating (ARC), and an ultrathin indium tin oxide (ITO) tunnel recombination layer is proposed. The proposed Model D achieved a simulated open-circuit voltage (Voc) of 1.92 V, short-circuit current density (Jsc) of 20.15 mA cm−2, fill factor (FF) of 91.2%, and power conversion efficiency (PCE) of 35.2% under AM1.5G illumination. The enhanced performance is attributed to improved optical management, efficient carrier extraction, suppressed non-radiative recombination, and optimised current matching between the perovskite and crystalline silicon sub-cells. The developed MATLAB framework provides a transparent, scalable, and reproducible platform for the design and optimisation of next-generation environmentally friendly tandem photovoltaic devices and provides a transparent and reproducible alternative for equation-level photovoltaic modelling and optimisation.