Title: High Thermoelectric Performance in 2D Sb₂Te₃ and Bi₂Te₃ Nanoplate Composites Enabled by Energy Carrier Filtering and Low Thermal Conductivity

Abstract

Thermoelectrics are an important class of materials with great potential in alternative energy applications. In this study, two-dimensional (2D) nanoplates of the layered chalcogenides, Sb₂Te₃ and Bi₂Te₃, are synthesized and composites of the two are investigated for their thermoelectric properties. The two materials, Sb₂Te₃ and Bi₂Te₃, were synthesized as hexagonal, 2D nanoplates via a colloidal polyol route. The as-synthesized Sb₂Te₃ and Bi₂Te₃ vary drastically from one another in their lateral and vertical dimensions as revealed by scanning electron microscopy and atomic force microscopy. The single crystalline nanoplate nature is deduced by high-resolution transmission electron microscopy and selected area electron diffraction. Nanoplates have well-defined hexagonal facets as seen in the scanning and transmission electron microscopy images. The nanoplates were consolidated as an anisotropic nanostructured pellet via spark plasma sintering. Preferred orientation observed in the powder X-ray diffraction pattern and scanning electron microscopy images of the fractured pellets confirm the anisotropic structure of the nanoplates. Thermoelectric properties in the parallel and perpendicular directions were measured, revealing strong anisotropy with a significant reduction to thermal conductivity in the perpendicular direction due to increased phonon scattering at nanoplate interfaces. All compositions, except that of the 25% Bi₂Te₃ nanoplate composite, behave as degenerate semiconductors withmore » increasing electrical resistivity as the temperature increases. The Seebeck coefficient is also increased dramatically in the nanocomposites, the highest reaching 210 μV/K for 15% Bi₂Te₃. The increase in Seebeck is attributed to energy carrier filtering at the nanoplate interfaces. Overall, these enhanced thermoelectric properties lead to a drastic increase in the thermoelectric performance in the perpendicular direction, with zT ~ 1.26, for the 15% Bi₂Te₃ nanoplate composite at 450 K.« less

Authors:

Kimberly, Tanner Q.  ^[1];

• Search DOE PAGES for author "Kimberly, Tanner Q."
• Search DOE PAGES for ORCID "0000-0003-0718-0414"

Ciesielski, Kamil M.  ^[2];

• Search DOE PAGES for author "Ciesielski, Kamil M."
• Search DOE PAGES for ORCID "0000-0002-9787-5967"

Qi, Xiao  ^[3];

• Search DOE PAGES for author "Qi, Xiao"
• Search DOE PAGES for ORCID "0000-0003-4884-6454"

Toberer, Eric S. ^[2]; Kauzlarich, Susan M.  ^[1]

• Search DOE PAGES for author "Kauzlarich, Susan M."
• Search DOE PAGES for ORCID "0000-0002-3627-237X"

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+ Show Author Affiliations

1. Univ. of California, Davis, CA (United States)
2. Colorado School of Mines, Golden, CO (United States)
3. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Molecular Foundry

Publication Date:

Mon Jun 05 00:00:00 EDT 2023

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE); National Science Foundation (NSF)

OSTI Identifier:

2234211

Grant/Contract Number:  

AC02-05CH11231; DMR-2001156; DMR-1555340

Resource Type:

Accepted Manuscript

Journal Name:

ACS Applied Electronic Materials

Additional Journal Information:

Journal Name: ACS Applied Electronic Materials; Journal ID: ISSN 2637-6113

Publisher:

ACS Publications

Country of Publication:

United States

Language:

English

Subject:

nanocomposites; colloidal synthesis; Bi₂Te₃; Sb₂Te₃; thermoelectrics; zT > 1; energy carrier filtering