Enhancing thermoelectric and mechanical properties of p-type Cu3SbSe4-based materials via embedding nanoscale Sb2Se3

Abstract

Cu3SbSe4, a promising p-type thermoelectric (TE) material consisting of earth-abundant, nontoxic, cost-efficient and eco-friendly constituent elements. However, its low TE performance is relatively poor because of the low carrier concentration and mobility. Herein, we synergistically optimize the electrical and thermal transport properties of Cu3SbSe4 via embedding nanoscale Sb2Se3. The Sb2Se3 nanophase markedly increases the carrier concentration and carrier effective mass simultaneously, resulting in a higher power factor of ∼1100 μW m−1 K−2. Surprisingly, Sb2Se3 nanophase induces high-density phase boundaries and dislocations, which significantly depress the lattice thermal conductivity. The multiple effects of incorporation of Sb2Se3 boost Cu3SbSe4 to an outstanding ZT value of ∼0.86 at 673 K for Cu3SbSe4 +1.5 mol% Sb2Se3 composite, which is ∼1.70 times as high as that of pristine Cu3SbSe4. It is highly remarkable that Cu3SbSe4 with nanoscale Sb2Se3 is mechanically robust, showing the Vickers hardness (Hv) and fracture toughness (KIC) of ∼2.54 GPa and ∼0.73 ± 0.02 MPa m½, which are ∼20% and ∼12% higher than those of pristine Cu3SbSe4, respectively. This work provides guidance for enhancing the comprehensive TE and mechanical properties of the copper-based chalcogenides by embedding nanophases.