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The efficiency of thermoelectric (TE) technology relies on the performance of TE materials. Substitution with heavy elements is an effective strategy in TE for enhancing phonon scattering without much affecting electrical transport properties. However, selecting suitable dopants to achieve a high thermoelectric figure-of-merit (ZT) poses a significant challenge. Thus, in this study, the efficacy of combined (Fe and Bi) co-substitution in CrSb2 is investigated as a promising strategy to enhance ZT by lowering thermal conductivity. A series of co-substituted Cr1-xFexBiySb2-y (x = 0, 0.25, 0.50, 0.75, 1 and y = 0.10, 0.15, 0.20,0.25) samples were synthesized via furnace reaction followed by spark plasma sintering technique. Phase analysis and temperature dependence TE transport properties were systematically studied on synthesized samples. Furthermore, to analyze the impact of disorder induced by Bi/Fe substitution, electronic structure calculation was performed using the projector augmented-wave method. Notably, Cr0.75Fe0.25Bi0.15Sb1.85 exhibited a low thermal conductivity of ~ 2.5 W m-1 K-1 at 300 K, which reduced to half compared to that of pristine CrSb2 (~ 5 W m-1 K-1). This reduction is attributed to the introduction of significant mass fluctuations and point defects along with the presence of Bi at grain boundaries by co-substitution. Consequently, a remarkable 90% enhancement in ZT (~0.021) at 350 K was achieved for Cr0.75Fe0.25Bi0.15Sb1.85 compared to that of pristine CrSb2 (ZT~0.012). This study can provide valuable insights into the rational design of effective dopants in other TE materials also.

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  This is the version of the article before peer review or editing, as submitted by an author to Nanotechnology.  IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it.  The Version of Record is available online at https://dx.doi.org/10.1088/1361-6528/ad6874

Keyword: thermoelectric

Date published: 2024-10-21

Publisher: IOP Publishing

Journal:

• Nanotechnology (ISSN: 13616528) vol. 35 issue. 43 435704

Funding:

• JST-Mirai Program JPMJMI19A1

Manuscript type: Author's version (Submitted manuscript)

MDR DOI: https://doi.org/10.48505/nims.4803

First published URL: https://doi.org/10.1088/1361-6528/ad6874

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Updated at: 2024-10-08 16:30:07 +0900

Published on MDR: 2024-10-08 16:30:09 +0900