Clarification of electronic and thermal transport properties of Pb-, Ag-, and Cu-doped p-type Bi0.52Sb1.48Te3

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 (n(c)), carrier mobility (mu(Hall)), density of state (DOS) effective mass (M*(d)), and electronic (K-ele), lattice (x(lat)), and bipolar thermal (K-bp) 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 Bi(0.52)Sla1(.48)Te(3) (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 ma with the doping content at n(c) < 10(20) cm(-3). (C) 2018 Published by Elsevier B.V.