Engineering the energy gap near the valence band edge in Mn-incorporated Cu3Ga5Te9 for an enhanced thermoelectric performance

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Cui, Jiaolin, Sun, Zheng, Du, Zhengliang and Chao, Yimin ORCID: https://orcid.org/0000-0002-8488-2690 (2016) Engineering the energy gap near the valence band edge in Mn-incorporated Cu3Ga5Te9 for an enhanced thermoelectric performance. Journal of Materials Chemistry C, 4 (34). pp. 8014-8019. ISSN 2050-7526

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Abstract

Cu3Ga5Te9-based compounds Cu3-xGa5MnxTe9 (x=0-0.2) with Mn substitution for Cu have been synthesized. The engineered energy gap (∆EA) between impurity and valence band is reduced from 44.4 meV at x=0 to 25.7 meV at x=0.1, which is directly responsible for the reduction of potential barrier for thermal excitation of carriers and enhancement in carrier concentration. However, the Seebeck coefficient shows an increasing tendency with the increasing of determined Hall carrier concentration (n). This anomalous behavior suggests that the Pisarenko plots under assumed effective masses do not fit the current relationship between the Seebeck coefficient and carrier density. With the combination of enhanced electrical conductivities and reduced thermal conductivities at high temperatures, the maximum thermoelectric (TE) figure of merit (ZT) of 0.81 has been achieved at 804 K with x=0.1, which is about 1.65 and 2.9 times the value of current and reported intrinsic Cu3Ga5Te9. The remarkable improvement in TE performance proves that we have succeeded in engineering the energy gap near the valence band edge upon Mn incorporation in Cu3Ga5Te9.

Item Type: Article
Faculty \ School: Faculty of Science > School of Chemistry
UEA Research Groups: Faculty of Science > Research Groups > Chemistry of Materials and Catalysis
Faculty of Science > Research Groups > Energy Materials Laboratory
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Depositing User: Pure Connector
Date Deposited: 24 Sep 2016 00:15
Last Modified: 22 Oct 2022 01:24
URI: https://ueaeprints.uea.ac.uk/id/eprint/59950
DOI: 10.1039/C6TC02745H

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