Effect of substitutional Pb doping on bipolar and lattice thermal conductivity in p-type Bi0.48Sb1.52Te3

Hyun Sik Kim, Kyu Hyoung Lee, Joonyeon Yoo, Jehun Youn, Jong Wook Roh, Sang Il Kim, Sung Wng Kim

Research output: Contribution to journalArticlepeer-review

38 Scopus citations

Abstract

Cation substitutional doping is an effective approach to modifying the electronic and thermal transports in Bi2Te3-based thermoelectric alloys. Here we present a comprehensive analysis of the electrical and thermal conductivities of polycrystalline Pb-doped p-type bulk Bi0.48Sb1.52Te3. Pb doping significantly increased the electrical conductivity up to ~2700 S/cm at x = 0.02 in Bi0.48-xPbxSb1.52Te3 due to the increase in hole carrier concentration. Even though the total thermal conductivity increased as Pb was added, due to the increased hole carrier concentration, the thermal conductivity was reduced by 14-22% if the contribution of the increased hole carrier concentration was excluded. To further understand the origin of reduction in the thermal conductivity, we first estimated the contribution of bipolar conduction to thermal conductivity from a two-parabolic band model, which is an extension of the single parabolic band model. Thereafter, the contribution of additional point defect scattering caused by Pb substitution (Pb in the cation site) was analyzed using the Debye-Callaway model. We found that Pb doping significantly suppressed both the bipolar thermal conduction and lattice thermal conductivity simultaneously, while the bipolar contribution to the total thermal conductivity reduction increased at high temperatures. At Pb doping of x = 0.02, the bipolar thermal conductivity decreased by ~30% from 0.47 W/mK to 0.33 W/mK at 480 K, which accounts for 70% of the total reduction.

Original languageEnglish
Article number763
JournalMaterials
Volume10
Issue number7
DOIs
StatePublished - 6 Jul 2017

Keywords

  • Bipolar conduction
  • Bismuth telluride
  • Lattice thermal conductivity
  • Thermoelectrics

Fingerprint

Dive into the research topics of 'Effect of substitutional Pb doping on bipolar and lattice thermal conductivity in p-type Bi0.48Sb1.52Te3'. Together they form a unique fingerprint.

Cite this