Probing the physical properties of Novel Lead-free double perovskites A2NaAsCl6 (A=K and Rb): A First-principles approach

Abstract

The structural, opto-electronic, and thermoelectric aspects of A2NaAsCl6 (A=K and Rb) have been considered for applications in renewable energy. Compound’s stabilities are promised by positive cohesive energy, formation energy, and tolerance factor. The structural parameters show that the lattice constant increases from K to Rb because the atomic radius of K is larger than that of Rb. With an optimised lattice constant, the band gap values for K2NaAsCl6 and Rb2NaAsCl6 are 3.522 eV and 3.473 eV, correspondingly. These materials are therefore widely used in optoelectronic and solar cell applications. Thermoelectric and thermodynamic properties are analysed by various parameters. The PF values at 300K are 1.72 × 1011 W/K2ms and 1.67 × 1011 W/K2ms, respectively. ZT values of 0.11 and 0.12 demonstrate how important they are for thermoelectric applications at room temperature. The results show that A2NaAsCl6 (A=K and Rb) has a wide bandgap and a high ZT value, making it a suitable candidate for thermoelectric and optoelectronic applications.