Influence of acceptor/donor densities and layer thicknesses on the efficiency of 2D ZnO/BFO/spiro-OMeTAD perovskite solar cells: a COMSOL simulation-based optimization

Abstract

The adverse effects of global warming and the continued reliance on hazardous energy sources, such as coal and petroleum, have intensified the global pursuit of clean and sustainable energy alternatives. Among these, solar energy emerges as the most viable option to meet the growing energy demands of an expanding population. Over the past decades, extensive research has focused on identifying optimal materials for solar cells to enhance their stability, cost-effectiveness, and efficiency. In this context, perovskite materials—particularly BiFeO₃—have gained significant attention as absorber materials due to their multifunctional properties, including room-temperature ferroelectricity and strong remanent polarization, which eliminate the need for a conventional p–n junction. This study employs COMSOL Multiphysics software to simulate a ZnO/BiFeO₃/spiro-OMeTAD solar cell structure, assuming ohmic front and back contacts. Key parameters, such as the acceptor and donor densities of states, as well as the thicknesses of BiFeO₃, ZnO, and spiro-OMeTAD layers, were systematically varied to evaluate their influence on the photovoltaic performance of the cell at room temperature. The results indicate that increasing the thickness of BiFeO₃ leads to a progressive enhancement in short-circuit current density, power output, and overall efficiency. In contrast, increasing the thicknesses of the ZnO and spiro-OMeTAD layers results in a decline in these performance metrics. Furthermore, variations in donor and acceptor densities significantly impact the solar cell's efficiency. This study offers valuable insights into optimizing material properties and device parameters for experimental applications, highlighting the potential of BiFeO₃-based perovskite materials as promising candidates for next-generation photovoltaic technologies.