Author(s): Yuan, W (Yuan, Wei); Deng, Q (Deng, Qian); Pan, D (Pan, Dong); An, X (An, Xiang); Zhao, CY (Zhao, Canyang); Su, WJ (Su, Wenjun); He, ZM (He, Zhengmin); Sun, Q (Sun, Qiang); Ang, R (Ang, Ran)

Source: JOURNAL OF MATERIALS CHEMISTRY A DOI: 10.1039/d3ta06594d  Early Access Date: NOV 2023  

Abstract: Optimizing n-type PbTe thermoelectric materials to match their better-performing p-type counterparts is critical for realizing their practical applications. To overcome this gap, dynamic doping, due to its temperature-dependent self-optimizing carrier concentration, has recently arisen as an effective method to improve the performance of n-type PbTe. However, their evitable dynamic compositional evolution must lead to structure evolution at elevated temperatures, which may have a negative effect on suppressing phonon transport, verified by the observed high lattice thermal conductivity (kappa(lat)) of Ag-doped n-type PbTe. Herein, we describe the significance of Mn alloying in enhancing the performance of Ag-doped n-type PbTe by creating a hierarchical structure to suppress thermal transport and improving the Seebeck coefficient by flattening the L point of the conduction band. Systematic characterization analysis reveals that the constructed hierarchical structure primarily consists of Ag2Te-decorated grain boundaries, dispersive MnTe nanoprecipitates, and atomic disorders induced by multi-doping in the matrix, which significantly suppressed kappa(lat) across the entire temperature range. In consequence, a high ZT similar to 1.4 of Ag0.03Pb0.95Mn0.05Te at 773 K and an average ZT similar to 0.8 of Ag0.03Pb0.99Mn0.01Te in the range of 323-823 K were obtained, which were ascribed to the weakening of the coupling between electron and phonon transport. This work demonstrates an upgraded approach to enhance the thermoelectric performance of dynamically-doped PbTe materials through unique structural design, which can be applied to other thermoelectric material systems with high performance.

Accession Number: WOS:001127197000001

Author Identifiers:

Author Web of Science ResearcherID ORCID Number

Ang, Ran         0000-0002-7229-9668

Pan, Dong         0000-0003-2067-6983

ISSN: 2050-7488

eISSN: 2050-7496