Structural, optoelectronic and thermoelectric properties of the new perovskites LiMCl3 (M = Pb or Sn): a DFT study

In this manuscript, structural, electronic, optical and thermoelectric properties of chloride perovskites LiMCl3 (M = Pb or Sn) have been studied using Density Functional Theory (DFT) implemented in ABINIT code. The exchange-correlation functionals is treated with Generalized Gradient Approximation of Perdew Burke Ernzerhof (GGA-PBE). Structural properties revealed that the equilibrium lattice parameters for LiPbCl3 and LiSnCl3 are 5.686 and 5.597 & Aring; respectively. These values were used to investigate the thermodynamic stability of these materials by evaluating the energy of formation. The negative formation energy results suggest that the synthesis of LiPbCl3 and LiSnCl3 perovskites is feasible. Further, electronic properties revealed that LiMCl3 (M = Pb and Sn) perovskites are semiconductors with indirect band gaps of 1.87 and 0.98 eV for LiPbCl3 and LiSnCl3, respectively. From the optical properties, we found that the studied materials have a high absorption coefficient, greater than 10(4) cm(-1) in the visible region, indicating their suitability as photovoltaic absorber materials. The results of the elastic properties show that both perovskites are stable and possess ductile behavior. In addition, thermoelectric properties of LiMCl3 (M = Pb and Sn) have been calculated and analyzed using the combination of electronic structure and Boltzmann transport theory. The thermoelectric efficiency results suggest that LiPbCl3 and LiSnCl3 could be potential candidates for thermoelectric devices for high-temperature applications.