Phase-Transition-Enhanced Thermoelectric Transport in Rickardite Mineral Cu3- xTe2

Mujde Yahyaoglu, Melis Ozen, Yurii Prots, Oussama El Hamouli, Vahe Tshitoyan, Huiwen Ji, Ulrich Burkhardt, Bertrand Lenoir, G. Jeffrey Snyder, Anubhav Jain, Christophe Candolfi, Umut Aydemir*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


The binary copper chalcogenides Cu2-δX (X = S, Se, and Te) have recently gained significant interest due to their high thermoelectric performance at moderate temperatures. In an effort to unveil new Cu-based compounds with promising thermoelectric potential, Cu3-xTe2 rickardite mineral emerged as a candidate based on a purely text mining approach applied by a machine learning method. Polycrystalline samples of Cu3-xTe2 within the homogeneity range (x = 0.1, 0.2) were successfully synthesized from the raw elements by a solid-state method. High-temperature powder X-ray diffraction combined with differential scanning calorimetry and specific heat measurements showed several reversible phase transitions at around 458, 640, and 647 K. Signatures of these transitions were observed on the electronic and thermal transport properties, measured over a broad range of temperatures (5-733 K). The transition undergone by this compound at 647 K results in a crossover from metallic-like to semiconducting-like properties. The combination of high power factor and low thermal conductivity in the high-temperature phase results in improved thermoelectric performances with a peak dimensionless thermoelectric figure-of-merit zT of ∼0.14 at 733 K. The synthetic rickardite mineral is an exciting candidate to be used as a phase change material in broad application areas such as in waste heat harvesting and photovoltaic systems.

Original languageEnglish (US)
Pages (from-to)1832-1841
Number of pages10
JournalChemistry of Materials
Issue number5
StatePublished - Mar 9 2021

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry


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