A DFT Calculations of Mechanical, Optoelectronic and Transport Properties of Cubic AMgI₃ (A = Li/Na) Halides for Photovoltaic and Energy Conversion Applications

Due to their rich and extraordinary properties, halide perovskites have gained attention over time for their applications in thermoelectric and solar cells. This paper investigates the properties of cubic halides AMgI₃ (A = Li/Na) compounds focusing on their optoelectronic and thermoelectric characteristics using the FP-LAPW method and semi-classical Boltzmann transport theory. The structural (− 43130.389030 Ry, − 43440.262047 Ry) and mechanical stability were confirmed by assessing the tolerance factor (0.81, 0.87) and formation energy (− 326.60, − 76.38), and by evaluating the elastic constants, respectively. The calculated value of Poisson ratio and Pugh ratio greater than their cutoff limit (2.29 and 2.18) reveal that our examined materials are ductile in nature. To examine the optoelectronic and transport properties the Trans-Bhala modified Becke Johnson potential (TB–mBJ) is employed. Using the TB–mBJ exchange – correlation potential function, the calculated indirect band gap values for LiMgI₃ and NaMgI₃ are 2.56 and 2.71 eV, respectively. These band gaps are suitable for solar energy harvesting due to their broad optical absorption ranging from infrared to visible light. To look at how individual atoms contributed, the partial and total densities of states were calculated. To investigate the possible application in renewable energy devices, we lastly compute the thermo-electric parameters, such as thermal (κ/τ) and electricity (σ/τ) conductivity, the Seebeck coefficient (S), energy factor (PF), and figure of merit (zT), which were analysed by BoltzTraP code within a range of temperatures (300 K–600 K) and chemical potentials.