Advanced computational study of electronic, optical, thermoelectric, and thermodynamic properties of quaternary Zintl KX2Cd2Sb3 (X = Ca, Sr) phases for energy application

초록

The Quaternary Zintl materials have gained great attention in recent time because to their unique structure and promising thermoelectric performance. In this paper, the quaternary Zintl compound KX2Cd2Sb3 (X = Ca, Sr) is thoroughly studied using the full-potential linearized augmented plane-wave plus local orbitals (FP-LAPW+lo) method within density functional theory. The exchange-correlation effects are treated using the GGA-PBE functional, while the modified Becke-Johnson (TB-mBJ) potential is employed to obtain accurate electronic properties. Band structures reveal these compounds are direct bandgap semiconductors. The complex quaternary Zintl phases exhibit promising electronic and optical properties, highlighting their potential for optoelectronic applications. The thermoelectric performance measured using the BoltzTraP code, indicates a notable ZT value of 0.70 for KCa2Cd2Sb3 and 0.71 for KSr2Cd2Sb3 at 800 K, establishing it as very effective for thermoelectric application. Furthermore, their favorable thermoelectric properties, including high Seebeck coefficients and intrinsically low lattice thermal conductivity, make them attractive candidates for thermoelectric generators capable of efficient waste heat recovery and sustainable energy conversion.

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