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Low‐dimensional thermoelectric materials systems are proven to possess improved thermoelectric performance, either by enhancing the power factorS2σthrough quantum confinement, or decreasing thermal conductivity with numerous interfaces. The 2D tellurium, also called tellurene, is a newly discovered 2D material which showed great potential for thermoelectric applications. In this article, high‐quality tellurene‐like nanosheets are synthesized by the hydrothermal method and assembled into nanostructured bulk materials by low‐temperature hot press, and their thermoelectric performance is investigated. Ultraviolet–ozone treatment is used to remove organic surface ligands. Doping is realized with surface doping with chalcogenidometalates. It is found that the Seebeck coefficient and the thermal conductivity of the nanosheet‐assembled bulk samples increased by ≈20% and decreased by 43% compared to bulk tellurium, respectively. Meanwhile, the carrier mobility is approaching, yet still lower than bulk tellurium. Overall, the best bulk sample possesses azTof 0.1 at room temperature which is comparable to bulk Te. By further improving the mobility, this solution processable material can provide useful thermoelectric performance for room‐temperature applications.
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The Thermoelectric Properties of Bismuth Telluride
Abstract Bismuth telluride is the working material for most Peltier cooling devices and thermoelectric generators. This is because Bi2Te3(or more precisely its alloys with Sb2Te3for p‐type and Bi2Se3for n‐type material) has the highest thermoelectric figure of merit,zT, of any material around room temperature. Since thermoelectric technology will be greatly enhanced by improving Bi2Te3or finding a superior material, this review aims to identify and quantify the key material properties that make Bi2Te3such a good thermoelectric. The largezTcan be traced to the high band degeneracy, low effective mass, high carrier mobility, and relatively low lattice thermal conductivity, which all contribute to its remarkably high thermoelectric quality factor. Using literature data augmented with newer results, these material parameters are quantified, giving clear insight into the tailoring of the electronic band structure of Bi2Te3by alloying, or reducing thermal conductivity by nanostructuring. For example, this analysis clearly shows that the minority carrier excitation across the small bandgap significantly limits the thermoelectric performance of Bi2Te3, even at room temperature, showing that larger bandgap alloys are needed for higher temperature operation. Such effective material parameters can also be used for benchmarking future improvements in Bi2Te3or new replacement materials.
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- PAR ID:
- 10461107
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Electronic Materials
- Volume:
- 5
- Issue:
- 6
- ISSN:
- 2199-160X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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