Band engineering enhances thermoelectric performance of Ag-doped Sn0.98Se

Jianglong Zhu; Fujie Zhang; Xiaobo Tan; Ruiheng Li; Shan He; Ran Ang

doi:10.1088/1361-648X/acea13

Band engineering enhances thermoelectric performance of Ag-doped Sn_0.98Se

J Phys Condens Matter. 2023 Aug 1;35(43). doi: 10.1088/1361-648X/acea13.

Authors

Jianglong Zhu¹, Fujie Zhang¹, Xiaobo Tan¹, Ruiheng Li¹, Shan He¹, Ran Ang^{1

2}

Affiliations

¹ Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, People's Republic of China.
² Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610065, People's Republic of China.

PMID: 37487493
DOI: 10.1088/1361-648X/acea13

Abstract

Ag doping can effectively increase the carrier concentration ofp-type SnSe polycrystalline, thereby enhancing the thermoelectric (TE) performance. However, the key role of the transport valence band in Ag-doped SnSe remains unclear. Particularly, understanding the influence of evaluating the optimal balance between band convergence and carrier mobility on weighted mobility is a primary consideration in designing high-performance TE materials. Here, we strongly confirm through theoretical and experimental evidence that Ag-doped Sn_0.98Se can promote the evolution of valence bands and achieve band convergence and density of states distortion. The significantly increased carrier concentration and effective mass result in a dramatic increase in weighted mobility, which favors the achievement of superior power factors. Furthermore, the Debye model reveals the reasons for the evolution of lattice thermal conductivity. Eventually, a superior average power factor and averagezTvalue are obtained in the Ag-doped samples in both directions over the entire test temperature range. This strategy of improving TE performance through band engineering provides an effective way to advance TEs.

Keywords: band engineering; p-type SnSe polycrystalline; thermoelectric materials; weighted mobility.