Exploring the structural, electronic, optical, transport, and photovoltaic properties of Rb2LiGa(Br/I)6 using DFT and SCAPS-1D simulations

Lead-free double perovskite halides are attracting considerable interest in the optoelectronics sector due to their remarkable electronic, optical, and transport properties. These materials are not only stable and easy to synthesize but also present a wide range of potential applications. This study investigates the fascinating characteristics of Rb2LiGa(Br/I)(6), focusing on its structural, electronic, optical, transport, and photovoltaic attributes. Our findings indicate that Rb2LiGaBr6 and Rb2LiGaI6 have band gaps of 1.19 eV and 1.13 eV, respectively, highlighting their versatility for various applications. Both compounds exhibit exceptional optical properties, featuring high absorption coefficients and optical conductivity, along with low reflectivity throughout the UV-visible spectrum, positioning them as excellent candidates for solar cell technologies. Moreover, Rb2LiGa(Br/I)(6) demonstrates impressive thermoelectric performance, with high figure-of-merit (ZT) values between 200 K and 800 K, indicating their potential as effective thermoelectric materials. Consequently, this study offers valuable insights for the development of efficient double perovskite-based solar cells. Encouraged by the outstanding absorption and optical conductivity of Rb2LiGa(Br/I)(6), we simulated an Au/Cu2O/Rb2LiGa(Br/I)(6)/TiO2/FTO solar cell. Our results reveal that the modeled solar cell, Au/Cu2O/Rb2LiGaI6/TiO2/FTO, achieves an efficiency of 26.48%, surpassing previous reports. This research sets a new benchmark for high-performance double perovskite-based solar cells and lays the foundation for future advancements in this exciting area.