Enhanced thermoelectric properties in Ag-rich AgSbSe2

First-Principles Calculations of Thermoelectric Transport Properties of Quaternary and Ternary Bulk Chalcogenide Crystals

Chalcogenide crystals have a wide range of applications, especially as thermoelectric materials for energy conversion. Thermoelectric materials can be used to generate an electric current from a temperature gradient based on the Seebeck effect and based on the Peltier effect, and they can be used in cooling applications. Using first-principles calculations and semiclassical Boltzmann theory, we have computed the Seebeck coefficient, electrical conductivity, electronic thermal conductivity, power factor, and figure of merit of 30 chalcogenide crystals. A Quantum Espresso package is used to calculate the electronic properties and locate the Fermi level. The transport properties are then calculated using the BoltzTraP code. The 30 crystals are divided into two groups. The first group has four crystals with quaternary composition (A₂BCQ₄) (A = Tl; B = Cd, Hg; C = Si, Ge, Sn; Q = S, Se, Te). The second group contains 26 crystals with the ternary composition (A’B’Q₂) (A’ = Ag, Cu, Au, Na; B’ = B, Al, Ga, In; Q = S, Se, Te). Among these 30 chalcogenide crystals, the results for 11 crystals: Tl₂CdGeSe₄, Tl₂CdSnSe₄, Tl₂HgSiSe₄, Tl₂HgSnS₄, AuBSe₂, AuBTe₂, AuAlTe₂, AuGaTe₂, AuInTe₂, AgAlSe₂, and AgAlTe₂ are revealed for the first time. In addition, temperature-dependent transport properties of pure and doped AgSbSe₂ and AgSbTe₂ crystals with dopant compositions of AgSb_0.94Cd_0.06Te₂ and AgSbTe_1.85Se_0.15 were explored. These results provide an excellent database for bulk chalcogenides crucial for a wide range of potential applications in renewable energy fields.

Cation disorder and bond anharmonicity synergistically boosts the thermoelectric performance of p-type AgSbSe2

Atomic bonding with simple 1D spring and ball model for the phonon–phonon interaction, which arises from 5s2 lone pair electrons.