1 research outputs found
Thermoelectric Performance of Surface-Engineered Cu<sub>1.5–<i>x</i></sub>Te–Cu<sub>2</sub>Se Nanocomposites
Cu2–xS and Cu2–xSe have recently been reported as
promising thermoelectric
(TE) materials for medium-temperature applications. In contrast, Cu2–xTe, another member of the copper
chalcogenide family, typically exhibits low Seebeck coefficients that
limit its potential to achieve a superior thermoelectric figure of
merit, zT, particularly in the low-temperature range
where this material could be effective. To address this, we investigated
the TE performance of Cu1.5–xTe–Cu2Se nanocomposites by consolidating surface-engineered Cu1.5Te nanocrystals. This surface engineering strategy allows
for precise adjustment of Cu/Te ratios and results in a reversible
phase transition at around 600 K in Cu1.5–xTe–Cu2Se nanocomposites, as systematically
confirmed by in situ high-temperature X-ray diffraction combined with
differential scanning calorimetry analysis. The phase transition leads
to a conversion from metallic-like to semiconducting-like TE properties.
Additionally, a layer of Cu2Se generated around Cu1.5–xTe nanoparticles effectively inhibits
Cu1.5–xTe grain growth, minimizing
thermal conductivity and decreasing hole concentration. These properties
indicate that copper telluride based compounds have a promising thermoelectric
potential, translated into a high dimensionless zT of 1.3 at 560 K