Strategic integration of electron transport layer for high-performance optimized lead-free double perovskite solar cells with temperature dependence

Perovskite solar cells (PSCs) are emerging as promising candidates for next-generation photovoltaic technologies, primarily due to their high efficiency and cost-effective manufacturing. A critical challenge in maximizing PSC performance lies in achieving consistent and efficient charge extraction and transport. This study investigates the energy alignment and electron transport in a ZnSe-based electron transport layer (ETL), focusing on their optical and electrical properties to enhance the efficiency of lead-free double perovskite solar cells. We utilize the 1D Solar Cell Capacitance Simulator (SCAPS-1D) to evaluate a lead-free double perovskite (Cs2BiAgI6) light absorber, noted for its environmental compatibility. By strategically manipulating key parameters such as doping density and defect concentration, along with optimizing layer thickness, we significantly enhance the power conversion efficiency (PCE) of Cs2BiAgI6-based double PSCs. Particularly, the incorporation of ZnSe as the ETL leads to an optimized PCE of 30.19%. We examine the impact of three different hole transport layers (HTLs) on device performance: MoO3, Cu2O, and spiro-OMeTAD. We also investigate how fluctuations in operating temperature affect the PCE of Cs2BiAgI6 in real time. Our findings highlight the critical role of the ETL in improving charge transport, offering valuable insights for the development and practical application of high-performance double PSCs.