Doping effects on the thermoelectric properties of Cu₃SbSe₄

We present the first systematic doping study on the ternary semiconductor Cu₃SbSe₄. We have developed a novel synthesis procedure that produces high-quality polycrystalline samples with hole concentrations an order of magnitude lower than have previously been reported for the undoped compound. The hole concentration can be increased by adding small amounts of either Ge or Sn on the Sb site. The power factor increases with increasing doping, reaching a maximum value of 16 μW/cmK₂. The thermoelectric properties are optimized for the 2% Sn doped compound which has ZT = 0.72 at 630 K, rivaling that of state-of-the-art thermoelectric materials in this temperature range.