The feasibility of using Bi2Te3-based alloys in low-grade heat thermoelectric power generation has been intensively investigated via a substitutional doping approach over the last decade. However, the comprehensive and quantitative understanding of the electronic and thermal transport parameters of doped Bi2Te3-based alloys including their carrier concentration (nc), carrier mobility (μHall), density of state (DOS) effective mass (md∗), and electronic (κele), lattice (κlat), and bipolar thermal (κbp) conductivities is still elusive. The understanding of these parameters is a prerequisite for designing the modules for real-time applications. In this study, we investigated the effect of Pb, Ag, and Cu doping on the thermoelectric transport parameters of p-type Bi0.52Sb1.48Te3 (BST) both theoretically and experimentally. The thermoelectric transport properties of BST and their temperature dependences could be systematically tuned in a low-temperature range by controlled doping of Pb, Ag, and Cu mainly because of the increased concentration of the majority hole carriers. In addition, a zT value of 1 could be obtained over the wide temperature range of 300–400 K by optimizing the doping elements and contents because of the synergetic effect of the suppression of bipolar conduction at higher temperatures and the gradual increase in md∗ with the doping content at nc < 1020 cm−3.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea ( NRF ) Grant ( 2017R1A2A1A17069528 ) funded by the Korea government ( MSIT ). KK is grateful for financial support from Yonsei University Research Fund (Post Doc. Researcher Supporting Program) of 2017 (project no.: 2017-12-0039 ).
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry