First Principles Study of Structral, Electronic, and Optical Proeprties of Lead Free Double Perovskites Rb2LiTlX6 (X = Cl, Br, I) for Optoelectronics Applications

Abstract

The presently, the renewable energy becomes the important source in the world because of shortage of oil and fossil sources and their hazardous. The solar cell is the main frontiers of cheap and clean renewable energy. We have chosen to lead free double perovskites Rb₂LiTlX₆ (X = Cl, Br, I) for structural, electronic, and optical applications because of their stable structure and direct band gaps. For the calculations, the modified Becke and Johnson potential has been applied (mBJ). The lattice constants are increase from Cl to I while bulk modulus decreases. The phase stability ensures the cubic phase with space group 221_Fm3m. The band structures and density of states show the band gabs (2.62, 1.39, & 0.14) eV. The ideal band gap of Rb₂LiTlBr₆ ensure the absorption of light in the visible region which has significant importance for solar cells applications.