Computational analysis of Cs2TlInY6 (Y = Cl, Br, I) halide double perovskites: insights from TB-mBJ and Hartree–Fock (HF) calculations for energy-related properties
摘要
First-principles calculations were performed using the WIEN2k package to find out the physical characteristics and structural stability of Cs-based halide double perovskites Cs2TlInY6 (where Y = Br, Cl, and I) within the context of density functional theory (DFT) and ab-initio molecular dynamics (AIMD). These compounds exhibit structural stability, as indicated by their negative values of formation and ground state energies. The electronic band structure reveals that Cs2TlInY6 (Y = Cl, Br and I) exhibits semiconducting behavior with indirect band gaps of 3.52 eV, 2.46 eV, and 1.31 eV, respectively. These band gaps were computed via a modified Becke-Johnson approximation methodology, while the corresponding values via Hartree–Fock (HF) are 4.70 eV, 3.21 eV, and 2.67 eV, which is known for its improved accuracy in band gap analysis. The compounds exhibit strong optical conductivity and maximum output in the visible spectrum of solar energy, alongside peak absorption for all materials, although reflectivity is reduced in this region, it renders them appropriate for optoelectronic and solar cell applications. All compounds exhibit mechanical and dynamic stability with a brittle characteristic; moreover, the covalent bonding nature is supported by Cauchy pressure, which yields negative values. Additionally, the thermoelectric properties of these compounds were analyzed to evaluate their potential for thermoelectric applications. The double perovskites exhibit favorable power factors, Seebeck coefficients, and electronic figures-of-merit, indicating their promise as p-type thermoelectric materials for further investigation.
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