Computational exploration of Cs2LiMoX6 (X=Cl, I) halide double perovskites: Unveiling energy storage potentials

Density functional theory (DFT) simulations were conducted to investigate the physical characteristics of materials Cs2LiMoCl6 and Cs2LiMoI6. The magnetic and electronic features were examined using the Perdew, Burke, and Ernzerhof generalized-gradient approximation (PBE-GGA). Confirmation of the semiconductor behavior was attained through the spin-resolved density of states (DOS) and band structure (BS) plots. In this investigation, the computed band gap (Eg) values for Cs2LiMoI6 are identified as 0.96 eV in the spin-down channel and 1.76 eV in the spin-up channel. Likewise, for Cs2LiMoCl6, the Eg is determined to be 3.35 eV in the spin-down channel and 1.63 eV in the spin-up channel. From magnetic characteristics, the magnetic moments (μB) of 3.02436 μB and 3.00332 μB are calculated for Cs2LiMoCl6 and Cs2LiMoI6, respectively. The ferromagnetic (FM) nature is observed from the integral values of the magnetic moment. The Mo-4d-t2g orbitals play a pivotal role in determining the magnetic properties observed in perovskite materials. The study also explored optical properties, and the values of ε1(ω) at zero energy are approximately 4.84 and 3.20 for Cs2LiMoI6 and Cs2LiMoCl6, respectively. The maximum values of σ(ω) are observed to be 4631 (Ω cm)−1 and 3618 (Ω cm)−1 at 6.24 eV and 8 eV for Cs2LiMoI6 and Cs2LiMoCl6, respectively, signifying their suitability to the UV light region. Overall, these findings suggest the suitability of both materials for photovoltaics and other related applications.