The low and high temperature thermoelectric properties of Sb doped Cu2SnSe3

• Pristine as well as Sb doped samples are in single phase.
• Electrical resistivity and Seebeck data follow Variable hopping model at low temperatures.
• Thermal conductivity decreases with Sb content.
• ZT = 0.0137 was achieved at 400 K for the sample Cu2Sn0.99Sb0.01Se3.

The effect of Sb doping on the thermoelectric properties of Cu2SnSe3 was investigated. The Cu2Sn1 − xSbxSe3 (0 ≤ x ≤ 0.04) compounds were prepared by solid state synthesis. The powder X-ray diffraction pattern of the samples showed a cubic structure (space group F4¯3m). The electrical resistivity decreased with increase in Sb content up to x = 0.02, then it increased with further increase in x. The electrical resistivity data follows variable hopping model at low temperatures. The Seebeck coefficient for all the samples is positive and analysis of data confirms that the variable hopping process is operative at low temperatures. The thermal conductivity is found to decrease with increase in Sb concentration, presumably due to point-defect scattering as a result of Sb substitution. The highest value of figure of merit at 400 K is equal to 0.0137 for the sample Cu2Sn0.99Sb0.01Se3 which is about eight times greater than that of the pristine sample.

Temperature dependence of figure of merit (ZT) of Cu2Sn1 − xSbxSe3 (0 ≤ x ≤ 0.04). Inset shows the variation of power factor (PF) with temperature for all the samples.Figure optionsDownload as PowerPoint slide