Thermoelectric Transport Properties of Co0.5Fe0.5Se2, Co0.5Fe0.5Te2, and Their Solid-Solution Compositions

Sang Jeong Park, Seyun Kim, Okmin Park, Se Woong Lee, Sang il Kim

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Transition-metal chalcogenides with tunable electronic transport properties and unique crystal structures have attracted much attention as potential thermoelectric materials. In this study, the electrical, thermal, and thermoelectrical transport properties of Co0.5Fe0.5Se2, Co0.5Fe0.5Te2 and a series of solid-solution compositions (Co0.5Fe0.5(Se1−yTe y)2, y = 0.25, 0.5, and 0.75) were investigated. Co0.5Fe0.5Se2 and Co0.5Fe0.5Te2 polycrystalline alloys exhibited high power factors of 1.37 and 1.53 mW/mK2 at 600 K, respectively, and their solid-solution compositions exhibited lower power factors between 0.38 and 0.81 mW/mK2. The lattice thermal conductivities of Co0.5Fe0.5Se2 and Co0.5Fe0.5Te2 were 2.87 and 1.71 W/mK at 300 K, respectively, and their solid-solution compositions exhibited lower lattice thermal conductivities between 0.96 and 1.98 W/mK. Consequently, the thermoelectric figure of merit (zT) of the Co0.5Fe0.5Se2 and Co0.5Fe0.5Te2 polycrystalline alloys was 0.16 and 0.18 at 600 K, respectively, and the zT of their solid-solution composition exhibited lower values between 0.04 and 0.09. As the solid-solution composition exhibited a lower thermoelectric performance than the Co0.5Fe0.5Se2 and Co0.5Fe0.5Te2 polycrystalline alloys, the lower thermoelectric performance was analyzed and discussed. Graphical Abstract: [Figure not available: see fulltext.].

Original languageEnglish
JournalElectronic Materials Letters
DOIs
StateAccepted/In press - 2023

Keywords

  • CoSe
  • CoTe
  • FeSe
  • FeTe
  • Solid solution
  • Thermoelectric
  • Transition metal chalcogenide

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