Enhanced Thermoelectric Performance through Tuning Bonding Energy in Cu2Se1-xSx Liquid-like Materials

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  • Kunpeng Zhao, Shanghai Institute of Ceramics Chinese Academy of Sciences, Chinese Academy of Sciences
  • ,
  • Anders Bank Blichfeld, Norwegian University of Science and Technology (NTNU), Trondheim,
  • Hongyi Chen, Shanghai Institute of Ceramics Chinese Academy of Sciences, Chinese Academy of Sciences
  • ,
  • Qingfeng Song, Shanghai Institute of Ceramics Chinese Academy of Sciences, Chinese Academy of Sciences
  • ,
  • Tiansong Zhang, Shanghai Institute of Ceramics Chinese Academy of Sciences
  • ,
  • Chenxi Zhu, Shanghai Institute of Ceramics Chinese Academy of Sciences, Chinese Academy of Sciences
  • ,
  • Dudi Ren, Shanghai Institute of Ceramics Chinese Academy of Sciences
  • ,
  • Riley Hanus, Northwestern University, Northwestern University, Evanston, USA
  • ,
  • Pengfei Qiu, Shanghai Institute of Ceramics Chinese Academy of Sciences
  • ,
  • Bo B. Iversen
  • Fangfang Xu, Shanghai Institute of Ceramics Chinese Academy of Sciences
  • ,
  • G. Jeffrey Snyder, Northwestern University, Northwestern University, Evanston, USA
  • ,
  • Xun Shi, Shanghai Institute of Ceramics Chinese Academy of Sciences
  • ,
  • Lidong Chen, Shanghai Institute of Ceramics Chinese Academy of Sciences, Shanghai Institute of Materials Genome

Thermoelectric materials require an optimal carrier concentration to maximize electrical transport and thus thermoelectric performance. Element doping and composition off-stoichiometry are the two general and effective approaches for optimizing carrier concentrations, which have been successfully applied in almost all semiconductors. In this study, we propose a new strategy called bonding energy variation to tune the carrier concentrations in Cu2Se-based liquid-like thermoelectric compounds. By utilizing the different bond features in Cu2Se and Cu2S, alloying S at the Se sites successfully increases the bonding energy to fix Cu atoms in the crystal lattice to suppress the formation of Cu vacancies, leading to greatly reduced carrier concentrations toward the optimal value. Via a combination of the lowered electrical and lattice thermal conductivities and the relatively good carrier mobility caused by the weak alloy scattering potential, ultrahigh zT values are achieved in slightly S-doped Cu2Se with a maximal value of 2.0 at 1000 K, 30% higher than that in nominally stoichiometric Cu2Se.

Original languageEnglish
JournalChemistry of Materials
Volume29
Issue15
Pages (from-to)6367-6377
Number of pages11
ISSN0897-4756
DOIs
Publication statusPublished - 2017

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