Surface Chemistry and Band Engineering in AgSbSe2: Toward High Thermoelectric Performance
Article
Liu, Yu, Li, Mingquan, Wan, Shanhong, Lim, Khak Ho, Zhang, Yu, Li, Mengyao, Li, Junshan, Ibanez, Maria, Hong, Min and Cabot, Andreu. 2023. "Surface Chemistry and Band Engineering in AgSbSe2: Toward High Thermoelectric Performance." ACS Nano. 17 (12), pp. 11923-11934. https://doi.org/10.1021/acsnano.3c03541
Article Title | Surface Chemistry and Band Engineering in AgSbSe2: Toward High Thermoelectric Performance |
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ERA Journal ID | 35029 |
Article Category | Article |
Authors | Liu, Yu, Li, Mingquan, Wan, Shanhong, Lim, Khak Ho, Zhang, Yu, Li, Mengyao, Li, Junshan, Ibanez, Maria, Hong, Min and Cabot, Andreu |
Journal Title | ACS Nano |
Journal Citation | 17 (12), pp. 11923-11934 |
Number of Pages | 12 |
Year | 2023 |
Publisher | American Chemical Society |
Place of Publication | United States |
ISSN | 1936-0851 |
1936-086X | |
Digital Object Identifier (DOI) | https://doi.org/10.1021/acsnano.3c03541 |
Web Address (URL) | https://pubs.acs.org/doi/10.1021/acsnano.3c03541 |
Abstract | AgSbSe2 is a promising thermoelectric (TE) p-type material for applications in the middle-temperature range. AgSbSe2 is characterized by relatively low thermal conductivities and high Seebeck coefficients, but its main limitation is moderate electrical conductivity. Herein, we detail an efficient and scalable hot-injection synthesis route to produce AgSbSe2 nanocrystals (NCs). To increase the carrier concentration and improve the electrical conductivity, these NCs are doped with Sn2+ on Sb3+ sites. Upon processing, the Sn2+ chemical state is conserved using a reducing NaBH4 solution to displace the organic ligand and anneal the material under a forming gas flow. The TE properties of the dense materials obtained from the consolidation of the NCs using a hot pressing are then characterized. The presence of Sn2+ ions replacing Sb3+ significantly increases the charge carrier concentration and, consequently, the electrical conductivity. Opportunely, the measured Seebeck coefficient varied within a small range upon Sn doping. The excellent performance obtained when Sn2+ ions are prevented from oxidation is rationalized by modeling the system. Calculated band structures disclosed that Sn doping induces convergence of the AgSbSe2 valence bands, accounting for an enhanced electronic effective mass. The dramatically enhanced carrier transport leads to a maximized power factor for AgSb0.98Sn0.02Se2 of 0.63 mW m–1 K–2 at 640 K. Thermally, phonon scattering is significantly enhanced in the NC-based materials, yielding an ultralow thermal conductivity of 0.3 W mK–1 at 666 K. Overall, a record-high figure of merit (zT) is obtained at 666 K for AgSb0.98Sn0.02Se2 at zT = 1.37, well above the values obtained for undoped AgSbSe2, at zT = 0.58 and state-of-art Pb- and Te-free materials, which makes AgSb0.98Sn0.02Se2 an excellent p-type candidate for medium-temperature TE applications. |
Keywords | AgSbSe2; nanocrystal; solution processing; surface chemistry; band engineering; thermoelectricity |
ANZSRC Field of Research 2020 | 401605. Functional materials |
Public Notes | Files associated with this item cannot be displayed due to copyright restrictions. |
Byline Affiliations | Hefei University of Technology, China |
Zhejiang University, China | |
Pennsylvania State University, United States | |
Zhengzhou University, China | |
Chengdu University, China | |
Institute of Science and Technology Austria, Austria | |
School of Engineering | |
Centre for Future Materials | |
Catalonia Institute for Energy Research (IREC), Spain |
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