Unveiling X 2 LaAuI 6 Through First Principles Study: Photocatalytic, Optoelectronic, and Thermoelectric Properties

The advancement of materials science increasingly focuses on predicting novel and functional materials, often driven by rapid screening enabled through density functional theory calculations. The current work on structural, mechanical, optoelectronic, photocatalytic, and thermoelectric X 2 LaAuI 6 (X = K/Rb/Cs) were analyzed using DFT. Crystal structure stability was confirmed through the phonon dispersion, while optoelectronic and thermoelectric properties were investigated using TB‐mBJ and SOC exchange‐correlation potentials, revealing that these compounds X 2 LaAuI 6 (X = K/Rb/Cs) are indirect with an accurate value of 2.28, 2.23, and 2.23 eV, respectively. The ductile nature of these materials was confirmed by Poisson's ratio and Pugh's modulus. The prominent absorption peaks in the near‐visible region underscore the suitability of these compounds for solar cells and optoelectronic devices. SLME calculations indicated efficiencies of up to 7.5%, further support their potential for photovoltaic applications. Thermoelectric calculations were assessed using semi‐classical Boltzmann theory (SCBT) across the temperature range of 200–1000 K. The materials exhibited promising ZT metrics at 1000 K, with values of 0.88, 0.86, and 0.89 for X 2 LaAuI 6 (X = K/Rb/Cs), respectively. These findings highlight the potential of X 2 LaAuI 6 (X = K/Rb/Cs) compounds for applications in solar cells, thermoelectric devices, and photocatalysis.