First-Principles Study of Lead-Free Cs2NaGaBr6-xFx (x = 0.00, 0.22, 0.33) Perovskites for Next-Generation Functional Materials

In this work, a systematic density functional theory study on lead-free double perovskites Cs₂NaGaBr₆₋ₓFₓ (x = 0.00, 0.22, 0.33) is reported, which reveals the changes brought by F substitution on the structure, electronic, optical, mechanical and elastic properties of these compounds. This paper finds out the variations in electronic structure and band gap parameters along with the enhancement in optical response and absorption of these compounds, which suggests that halide engineering can play an important role in tuning the functionalities of these materials. The discussion on the elastic and mechanical properties of the materials helps in understanding the structural stability, mechanical strength for application of next generation materials.