Increasing the thermoelectric power factor of Ge17Sb2Te20 by adjusting the Ge/Sb ratio

Abstract

We have investigated the thermoelectric properties of Ge17Sb2Te20. This compound is a known phase change material with electronic properties that depend strongly on temperature. The thermoelectric properties of this compound can be tuned by altering the stoichiometry of Ge and Sb without the use of additional foreign elements during synthesis. This tuning results in a 26% increase in the thermoelectric power factor at 723 K. Based on a single parabolic band model we show that the pristine material is optimally doped, and thus, a reduction in the lattice thermal conductivity of pure Ge17Sb2Te20 should result in an enhanced thermoelectric figure of merit.

Excellent Thermoelectric Performance Realized in p-Type Pseudolayered Sb2Te3(GeTe)12 via Rhenium Doping

“…By means of Hall measurement (depicted in Figure d), the results of carrier concentration and mobility were in accordance with the aforementioned ratiocination that augment in electrical conductivity and reduction in Seebeck coefficient were due to the improvement of carrier concentration. In addition, Seebeck coefficients from our data and refs and were capable of being roughly fit into a Pisarenko line calculated with single parabolic band model with the effective mass m * = 2.8 m 0 at room temperature, as drawn in Figure e, which is much larger than 1.4 m 0 , in GeTe-based materials. Therefore, when calculated power factor values with the same model (details can be seen in the Supporting Information) as a function of carrier concentration at 1.4 m 0 (Figure f), the data from references , , and fit the line well, while the data from our samples present a higher power factor at the high-level carrier concentration area, which indicates that the appropriate value of carrier concentration in Sb 2 Te 3 (GeTe) 12 is larger than that in GeTe-based materials.…”

Argyrodite‐Type Cu8GeSe6–xTex (0 ≤ x ≤ 2): Temperature‐Dependent Crystal Structure and Thermoelectric Properties

“…Germanium antimony tellurides (GeTe) n Sb 2 Te 3 (GST materials) are known as thermoelectric materials with high figures of merit . Partial substitution of Te against Se improves the thermoelectric properties, e.g.…”

Tuning the Vacancy Concentration in Lithium Germanium Antimony Tellurides—Influence on Phase Transitions, Lithium Mobility, and Thermoelectric Properties

“…Solid State NMR. Static 7 Li NMR spectra were recorded with a Bruker MSL 400 spectrometer connected to an Oxford cryomagnet with a nominal field of 9.4 T, corresponding to a 7 Li Larmor frequency of 155.4 MHz. The measurements were performed with a commercial high-temperature NMR probe (Bruker) with the powdered samples being sealed in glass ampules.…”

“…The waiting time was set to 6 times the spin−lattice relaxation time T 1 to obtain fully relaxed spectra. 7 Li magic angle spinning (MAS) NMR spectra were measured with a Bruker AVANCE III spectrometer connected to a cryomagnet with a nominal field of 14.1 T using a commercial Bruker MAS probe with a spinning frequency of 25 kHz. The spectra were referenced against an aqueous solution of LiCl.…”

“…Presently, a large variety of highly efficient thermoelectric materials like PbTe, Bi 2 Te 3 , half-Heusler phases, clathrates, Zintl phases, metal oxides, and so forth are available for power generation applications. − To the same extent, germanium antimony tellurides (GST materials) (GeTe) n Sb 2 Te 3 have emerged as a promising class of thermoelectric materials. − Their properties can be tuned by a broad variety of homovalent substitutions, e.g., Sn 2+ , Cd 2+ , or Mn 2+ for Ge 2+ , − Se 2– for Te 2– , or In 3+ for Sb 3+ . These materials are characterized by high concentrations of cation vacancies, which are completely disordered in NaCl-type high-temperature (HT) phases. − At lower temperatures, vacancies tend to order and form layers.…”