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<p>The worldwide energy crisis necessitates the exploration of new materials for effective thermoelectric energy conversion. The thermoelectric figure of merit (<i>ZT</i>) determines thermoelectric material performance. In this paper, a systematic analysis of the electronic and thermal properties of ternary alkaline earth chalcogenides Ba<sub>2</sub>CdX<sub>3</sub> (X = S, Se) is conducted under density functional theory (DFT), as they have not been systematically explored for thermoelectric applications previously. Both the materials, Ba<sub>2</sub>CdS<sub>3</sub> (1.57&#xa0;eV) and Ba<sub>2</sub>CdSe<sub>3</sub> (2.12&#xa0;eV), are large-bandgap semiconductors. The valence band maximum (VBM) and conduction band minimum (CBM) lie at the gamma point. To study the transport properties, we employ theoretical models grounded on Boltzmann transport formalism to ascertain the electrical (<i>S</i>, <i>σ</i>, <i>S</i><sup>2</sup><i>σ</i>, <i>κ</i><sub>e</sub>) and phonon transport properties (<i>κ</i><sub>l</sub>). The electron–phonon scattering rate is calculated based on a simple model of deformation potential. The phonon dynamics study indicates that these materials have an intrinsic low lattice thermal conductivity at room temperature (i.e., <i>κ</i><sub>l</sub> &lt; 3&#xa0;Wm<sup>−1</sup>&#xa0;K<sup>−1</sup>), resulting from their intrinsic structural character, causing the predominance of Umklapp scattering, diminished group velocity, and low Debye temperature. These materials have poor lattice thermal conductivity without alloying and defect engineering. Such a low value <i>κ</i><sub>l</sub> will enhance thermal management compared to transition metal dichalcogenides or graphene-based devices. Our findings show that Ba<sub>2</sub>CdS<sub>3</sub> (Ba<sub>2</sub>CdSe<sub>3</sub>) is a <i>p</i>-type thermoelectric material. The obtained maximum value of the thermoelectric figure of merit (<i>ZT</i>) is 0.32 for Ba<sub>2</sub>CdS<sub>3</sub> and 0.59 for Ba<sub>2</sub>CdSe<sub>3</sub> at 800&#xa0;K. By tuning the carrier concentration and temperature, <i>p</i>-type Ba<sub>2</sub>CdSe<sub>3</sub> can be used as an efficient thermoelectric material.</p>

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Thermoelectric Potential of Ba-Metal Chalcogenides: A Theoretical Investigation Predicting Thermoelectric Performance in Ba2CdX3 (X = S, Se)

  • 期刊论文

  • 发表日期：

    2026年6月30日

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  • Nidhi

摘要

The worldwide energy crisis necessitates the exploration of new materials for effective thermoelectric energy conversion. The thermoelectric figure of merit (ZT) determines thermoelectric material performance. In this paper, a systematic analysis of the electronic and thermal properties of ternary alkaline earth chalcogenides Ba2CdX3 (X = S, Se) is conducted under density functional theory (DFT), as they have not been systematically explored for thermoelectric applications previously. Both the materials, Ba2CdS3 (1.57 eV) and Ba2CdSe3 (2.12 eV), are large-bandgap semiconductors. The valence band maximum (VBM) and conduction band minimum (CBM) lie at the gamma point. To study the transport properties, we employ theoretical models grounded on Boltzmann transport formalism to ascertain the electrical (S, σ, S2σ, κe) and phonon transport properties (κl). The electron–phonon scattering rate is calculated based on a simple model of deformation potential. The phonon dynamics study indicates that these materials have an intrinsic low lattice thermal conductivity at room temperature (i.e., κl < 3 Wm−1 K−1), resulting from their intrinsic structural character, causing the predominance of Umklapp scattering, diminished group velocity, and low Debye temperature. These materials have poor lattice thermal conductivity without alloying and defect engineering. Such a low value κl will enhance thermal management compared to transition metal dichalcogenides or graphene-based devices. Our findings show that Ba2CdS3 (Ba2CdSe3) is a p-type thermoelectric material. The obtained maximum value of the thermoelectric figure of merit (ZT) is 0.32 for Ba2CdS3 and 0.59 for Ba2CdSe3 at 800 K. By tuning the carrier concentration and temperature, p-type Ba2CdSe3 can be used as an efficient thermoelectric material.