Thermoelectric properties of Tl and I dual-doped Bi2Te3-based alloys

Abstract

Tl[Formula: see text]Bi[Formula: see text]Te[Formula: see text]I[Formula: see text] (x = 0, 0.05, 0.1 and 0.2) flower-like nanopowders were prepared successfully by the hydrothermal method. Then, the synthesized nanoparticles were pressed into bulks by hot-pressing. The thermoelectric (TE) properties of the Tl[Formula: see text]Bi[Formula: see text]Te[Formula: see text]I[Formula: see text] bulk samples were investigated and discussed. The results showed that the influences of Tl doping on the electrical resistivity and Seebeck coefficients of the Bi2Te3 is over that of I doping. Thus, the power factors of the dual-doped bulks are all less than that of the Bi2Te3 bulk. The thermal conductivities of the Tl[Formula: see text]Bi[Formula: see text]Te[Formula: see text]I[Formula: see text] bulk samples also remain at lower values. As a result, the ZT value of the optimized doped bulk Tl[Formula: see text]Bi[Formula: see text]Te[Formula: see text]I[Formula: see text] attains a value of 1.1 at 398 K.