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Optimizing seebeck coefficient and thermoelectric efficiency via innovative Nb doping techniques in W18O49
Author(s)
Le, Quy Nguyen Ngoc
Ohtaki, Michitaka
Phan, Thang Bach
Snyder, Gerald Jeffrey
Nguyen, Cuong Chi
Ho, Linh Nguyen Thi
Thi Tran, Nhu Hoa
Tran, Nhat Quang Minh
Date Issued
March 15, 2025
Type
Article
Abstract
In this study, we systematically investigate the thermoelectric properties of (NbxW1-x)18O49 compounds (0 ≤ x ≤ 0.20). Unlike conventional doping approaches that aim to introduce additional charge carriers to enhance electrical conductivity, our non-conventional method focuses on tuning the electronic structure of the W18O49 matrix by substituting W5 + with Nb5+ cations. This substitution reduces the maximum number of donating electrons from 108 to approximately 104, approaching the 98 electrons accepted by the anions. This electronic tuning results in a significant increase in the Seebeck coefficient to −133.717 μV/K and achieves a remarkable zT value of approximately 0.318 at 800℃. Additionally, Nb doping induces notable structural distortions, leading to modifications in morphology and a reduction in lattice thermal conductivity. Despite a decrease in electrical conductivity with higher Nb content, the overall thermoelectric performance is enhanced, highlighting the potential of (NbxW1-x)18O49 Pentacolumn structures for high-temperature thermoelectric applications.
Citation
Journal of Alloys and Compounds, 1020, 2025