Enhancing efficiency in TiO<sub>2</sub>/MAPbI<sub>3</sub>/GO perovskite solar cells: theoretical investigation of MAPbI<sub>3</sub> interlayer effects using SCAPS-1D simulation

Pursuing highly stable and efficient renewable energy solutions remains the driving force for developing perovskite solar cells (PSCs). Central to achieving these cells’ high and optimum performance is the accurate and intelligent design engineering of the device’s architecture. This theoretical study employs the simulation platform SCAPS-1D to systematically investigate the crucial role of the interlayer methylammonium lead iodide (MAPbI3) as an adsorber layer in encouraging the titanium dioxide (TiO2)/MAPbI3/graphene oxide (GO) heterostructure design. By strategic tuning of the MAPbI3 absorber layer, we successfully delivered a remarkable 20.8% power conversion efficiency (PCE) and fill factor (FF) of 80.5% at 300 K, significant improvements over the reference PCE of 11.6% and FF of 78.5%. Significant improvements were made by optimizing MAPbI3 thickness to 1.2 µm and narrowing its bandgap to 1.5 eV, allowing enhanced photon absorption and charge carrier separation and minimizing interface-mediated recombination losses. Importantly, changes to the TiO2 and GO layer thickness had a minimal impact on performance, emphasizing the absorber layer’s dominant role in controlling efficiency. Utilizing low-cost, low-toxicity materials such as abundant TiO2 and GO improves economic feasibility and scalability, and the optimized structure minimizes material consumption, all aligning with sustainable photovoltaic development. These results advance our understanding of PSC optimization and reflect the enormous potential of MAPbI3 materials for developing highly efficient, green alternatives to conventional solar technology, enabling future developments in stable, scalable, and environmentally friendly energy solutions.