The thermoelectric properties of Cu₂S are enhanced by doping tin with hydrothermal method

Doping can greatly reduce the lattice thermal conductivity of thermoelectric materials, which is considered as one of the effective ways to improve the thermoelectric properties of thermoelectric materials. First of all, we use the simple and environmentally friendly solution thermal method combined with the tube furnace sintering technology to explore the optimal temperature of sintering Cu₂S in the tube furnace. When the sintering temperature reaches 700 °C, we get the thermoelectric value of 0.21. Subsequently, Cu₂S thermoelectric materials doped with xmol%Sn (x = 0.5, 1, 3, 5) were prepared and the optimal concentration of Sn was explored. The Sn atom replaces the Cu atom with a smaller radius, greatly reducing the thermal conductivity of the matrix material. In the sample doped with 1%Sn, the total thermal conductivity reaches 0.31 WK⁻¹ m⁻¹, which is 22.5% lower than that of the pure phase sample. In addition, above 623 K, the conductivity of samples doped with 1%Sn is better than that of intrinsic samples, indicating that Sn doping can optimize the conductivity of Cu₂S to a certain extent. At 773 K, the ZT of Cu₂S + 1 mol%Sn can reach 0.51. 132% higher than undoped Cu₂S.This provides a new idea for the preparation and commercial application of Cu–S based thermoelectric materials.