Hf-Doping Effect on the Thermoelectric Transport Properties of n-Type Cu0.01Bi2Te2.7Se0.3

Applied Sciences

Jae-Hong Lim¹  Heesun Yang²  Hyun-Sik Kim²  Sang-il Kim³  JeongYun Hwang⁴  Sura Choi⁴  KyuHyoung Lee⁴  Soon-Mok Choi⁵ 

[1] Department of Materials Science and Engineering, Gachon University, Seongnam 13120, Korea;Department of Materials Science and Engineering, Hongik University, Seoul 04066, Korea;Department of Materials Science and Engineering, University of Seoul, Seoul 02504, Korea;Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Korea;Materials and Chemical Engineering, School of Energy, Korea University of Technology and Education, Cheonan 31253, Korea;

关键词: Bi₂Te₃;    thermoelectric;    Hf-doping;    effective mass;    lattice thermal conductivity;   

DOI  :  10.3390/app10144875

来源: DOAJ

【 摘 要 】

Polycrystalline bulks of Hf-doped Cu_0.01Bi₂Te_2.7Se_0.3 are prepared via a conventional melt-solidification process and subsequent spark plasma sintering technology, and their thermoelectric performances are evaluated. To elucidate the effect of Hf-doping on the thermoelectric properties of n-type Cu_0.01Bi₂Te_2.7Se_0.3, electronic and thermal transport parameters are estimated from the measured data. An enlarged density-of-states effective mass (from ~0.92 m₀ to ~1.24 m₀) is obtained due to the band modification, and the power factor is improved by Hf-doping benefitting from the increase in carrier concentration while retaining carrier mobility. Additionally, lattice thermal conductivity is reduced due to the intensified point defect phonon scattering that originated from the mass difference between Bi and Hf. Resultantly, a peak thermoelectric figure of merit zT of 0.83 is obtained at 320 K for Cu_0.01Bi_1.925Hf_0.075Te_2.7Se_0.3, which is a ~12% enhancement compared to that of the pristine Cu_0.01Bi₂Te_2.7Se_0.3.

【 授权许可】

Unknown