Promising thermoelectric properties in AgxMo9Se11 compounds (3.4 ≤ x ≤ 3.9)

International audiencePolycrystalline Mo9 cluster chalcogenides AgxMo9Se11 (3.4 ≤ x ≤ 3.9) have been prepared by powder metallurgy techniques, sintered by spark plasma sintering and characterized by x-ray diffraction. Their thermoelectric properties (electrical resistivity, thermopower, thermal conductivity) have been determined in the 300-800 K temperature range. The AgxMo9Se11 compounds show p-type conduction characteristics. The outstanding low lattice thermal conductivities give rise to a rather high value of the dimensionless thermoelectric figure of merit ZT of ∼ 0.65 at 800 K for x = 3.8-3.9, making this family of materials particularly promising for thermoelectric power generation applications