Vacancy Phonon Scattering and Thermoelectric Properties in In₂Te₃–SnTe Compounds

Abstract

Solid solution formation is a common and effective way to reduce the lattice thermal conductivity for thermoelectric materials because of additional phonon scattering by point defects and grain boundaries. In the present work we prepared In2Te3–SnTe compounds using a mild solidification technique and evaluated their thermoelectric properties in the temperature range from 318705 K. Measurements reveal that the transport properties are strongly dependent on the chemical composition  In2Te3 content, and lattice thermal conductivity significantly reduces above a minimum In2Te3 concentration, which can possibly be explained by an introduction of the vacancy on the indium sublattice and periodical vacancy planes. The highest thermoelectric figure of merit ZT of 0.19 can be achieved at 705 K, and a big improvement of In2Te3 based alloys would be expected if a proper optimization to the chemical compositions and structures were made.

Thermoelectric Properties of an Al-Doped In-Sn-Te-Based Alloy

“…The highest a value of (In 1.9 Al 0.1 Te 3 ) 0.08 (SnTe) 0.92 is 83 lV K À1 at 668 K, only slightly higher than that of the Al-free (In 2 Te 3 ) 0.08 (SnTe) 0.92 sample. 3 Jovovic et al 13 suggested that such an unchanged a value results from indium impurity levels that pin the Fermi level. Figure 4 shows the electrical conductivity (r) as a function of temperature for the two samples; the r value gradually decreases with increasing temperature.…”

“…2 Recent work in our group revealed that In-Sn-Te-based alloys have low electrical and thermal conductivity. 3 This low electrical conductivity might be caused by low carrier concentration and high carrier scattering. From the microstructural point of view, it seems easier to improve the electrical conductivity of this material rather than the Seebeck coefficient.…”

Enhanced Thermoelectric Properties of Sb2Te3 Thin Films by In Doping

“…Additionally, In has also been frequently considered as a doping element in Sb 2 Te 3 , which may lead to intrinsic vacancies with the high density at cation sites owing to the lattice mismatch between indium (In 3+ ) (In 3+ is supposed to substitute Sb 3+ ) and tellurium ions (Te 2− ) [25,26]. Therefore, TE performance should be enhanced via phonon-vacancy scattering, which plays a substantial role in reducing thermal conductivity [27][28][29]. In summary, In is a promising doping element for improving the TE properties of the Sb 2 Te 3 thin film.…”