Journal of Inorganic Materials ›› 2019, Vol. 34 ›› Issue (3): 294-300.DOI: 10.15541/jim20180303

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Optimizing Electrical and Thermal Transport Property in BiCuSeO Superlattice via Heterolayer-isovalent Dual-doping Approach

LI Zhou1, XIAO Chong2   

  1. 1. School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China;
    2. Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China;
  • Received:2018-07-04 Revised:2018-11-28 Published:2019-03-20 Online:2019-02-26
  • Supported by:
    Project funded by China Postdoctoral Science Foundation (2017M620261);National Postdoctoral Program for Innovative Talents (BX201700217);The Fundamental Research Funds for the Central Universities (WK2060190090);National Natural Science Foundation of China (21622107, 21805269)


Taking the dual-sublayer BiCuSeO superlattice thermoelectric material as an object, equivalent mono- and dual-doped samples were prepared by substitution of Bi and Cu atoms in the corresponding [Bi2O2]2+ sublayer and [Cu2Se2]2- sublayer with isovalent La and Ag atoms. Their thermoelectric properties and the defect modulation mechanism were studied. The results showed that La-Ag dual-doped sample could combine the advantages of mono-doped samples to achieve an relative high carrier mobility while moderately increasing the carrier concentration, thereby maximizing the electrical conductivity. At the same time, it can also induce a potential band convergenceeffect, achieving the low average band effective mass and high density of states effective mass at the same time, which finally endowed Bi0.98La0.02Cu0.98Ag0.02SeO with simultaneous high carrier mobility and Seebeck coefficient, as well as the optimized power factor (PF=σS2). On the other hand, due to the strong point defect scattering on the heat-carrying phonons, the lattice and total thermal conductivities of these isovalent doped samples were further reduced, which finally optimized the figure of merit (ZT). As a result, a high ZT value of 0.46 was achieved at 755K in the La-Ag dual-doped sample, which was superior to that of the pristine sample (0.27 at 755 K) as well as the mono-doped counterparts. Present work demonstrates that heterolayer-isovalent dual-doping with La/Ag equivalent atoms in BiCuSeO can synergistically modulate its thermoelectric transport parameters with significantly improved thermoelectric performance.


Key words: heterolayer dual-doping, BiCuSeO, thermoelectric property, electrical-thermal transport, synergistic modulation

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