Fabrication and Thermoelectric Properties of Ag₉TlTe_X (X=5.0∼6.0)

抄録

Polycrystalline samples of Ag₉TlTe₅ with different nominal compositions: Ag₉TlTe_X (X=5.0, 5.05, 5.1, 5.2, 5.3, 5.5, 5.7, 6.0) were prepared and the phase relations were studied by X-ray diffraction (XRD) analysis. The electrical resistivity, Seebeck coefficient and thermal conductivity of Ag₉TlTe_X (X=5.0∼5.5) were measured from room temperature to around 630 K. The dimensionless figure of merit (ZT) of Ag₉TlTe_5.0 was quit low (∼0.08), while those of other samples were very high (∼1.0). It was confirmed that the thermoelectric properties of Ag₉TlTe₅ are significantly influenced by a minimal compositional deviation and the high ZT was obtained when the tellurium content was slightly larger than the stoichiometric composition.