Improving the Photoelectric Conversion Efficiency of Cs2TiBr6-Based Perovskite Solar Cells Using a Theoretical Simulation Method

While lead-based perovskites stand out as a highly promising material for solar cells, there remains a notable concern related to the possibility of lead leakage. This study utilized the solar cell simulation software SCAPS-1D to explore strategies for enhancing the efficiency of lead-free perovskite solar cells (PSCs) and to elucidate the corresponding theoretical mechanisms. A model of the n–i–p FTO/TiO2/Cs2TiBr6/P3HT/Au structure was developed. Employing various modification strategies in experimental setups, the impact of crucial parameters on device performance was investigated by manipulating specific variables. This systematic approach allowed for the identification of the most optimal parameter configuration for enhanced device performance. The device performance was thoroughly examined by evaluating key parameters such as transport layer mobility, energy-level matching properties, interface defect concentration, interface capture cross-section area, and perovskite defect density/thickness. The investigation revealed that a substantial enhancement in device performance can be achieved by minimizing the defect density in the perovskite, augmenting the mobility of the transport layer, refining the energy-level alignment with the perovskite, and reducing the interface capture area. The device simulation ultimately resulted in a conversion efficiency of 16.86%. This study provides valuable guidelines for the research and development of novel lead-free double PSCs.