In this work, polycrystalline n-type Mg2Si0.30Sn0.67Bi0.03 dispersed with x wt % β-SiC nanoparticles (x = 0, 0.5, 1.0, 1.5, and 3.0) thermoelectric materials were fabricated by a solid-state reaction in a low-cost container, consolidated by hot-pressing. We obtained figure of merit values zT above 1.4 at 773 K along with enhanced mechanical properties by adding β-SiC into an Mg2Si0.30Sn0.67Bi0.03 matrix. Incorporation of SiC nanoparticles has thusly simultaneously increased toughness and, depending on the SiC content, thermoelectric performance. The peak figure of merit was improved from zT = 1.33 for Mg2Si0.30Sn0.67Bi0.03 to 1.45 for Mg2Si0.30Sn0.67Bi0.03 with 3 wt % at 773 K.

BaCuSiTe3 was prepared from the elements in a solid-state reaction at 973 K, followed by slow cooling to room temperature. This telluride adopts a new, hitherto unknown structure type, crystallizing in the noncentrosymmetric space group Pc with a = 7.5824(1) Å, b = 8.8440(1) Å, c = 13.1289(2) Å, β = 122.022(1)°, and V = 746.45(2) Å3 (Z = 4). The structure consists of a complex network of two-dimensionally connected CuTe4 tetrahedra and ethane-like Si2Te6 units with a Si–Si bond. This semiconducting material has an optical band gap of 1.65 eV and a low thermal conductivity of 0.50 W m–1 K–1 at 300 K. Calculations of its optical properties revealed a moderate birefringence of 0.23 and a second-order harmonic generation response of d eff = 3.4 pm V–1 in the static limit.

Increasing the Te amount, y in BaCu6−xSe1−yTe6+y, causes higher electrical conductivity by increasing the Cu deficiencies for steric reasons.

This thallium telluride is bestowed with an ultralow thermal conductivity in comparison to state-of-the-art thermoelectrics.