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Enhancing thermoelectric properties of bismuth telluride and germanium telluride thin films for wearable energy harvesting

Enhancing thermoelectric properties of bismuth telluride and germanium telluride thin films for wearable energy harvesting
Enhancing thermoelectric properties of bismuth telluride and germanium telluride thin films for wearable energy harvesting
High performance semiconducting thin films enable the implementation of thermoelectric generators as energy harvesters for wearable applications. The optimization of material properties is critical in such applications, as restrictions introduced by the substrates on deposition temperature and active layer size, impose fundamental limitations on performance. Here we present the optimization of sputtered bismuth telluride, BiTe, and germanium telluride, GeTe, annealed at 300 ºC allowing comfortable development on polyimide substrates. The crystal structure and material composition of the films, before and after annealing, were measured by X-ray diffraction and X-ray photoelectron spectroscopy to reveal the changes in the material that enhanced the performance. The power factor of the BiTe films increased post-anneal up to 2.2 μW/cmK2, whilst the GeTe increased over 5 orders of magnitude to 7.6 μW/cmK2. A flexible thermoelectric generator was fabricated with pairs of alternating annealed BiTe and GeTe strips, reaching 7 nW per pair of output power at a temperature difference of 20 °C. Using this micro-fabrication process of thin films, compatible to roll-to-roll technologies, the physical dimensions of the generators can be tuned to deliver the required power, for providing storage energy for on-demand devices such as periodic sensing.
Bismuth telluride, Flexible thermoelectric generators, Germanium telluride, Post-annealing, Sputtering, Thin film, Wearable technology
0040-6090
1-12
Morgan, Katrina
2b9605fc-ac61-4ae7-b5f1-b6e3d257701d
Zeimpekis, Ioannis
a2c354ec-3891-497c-adac-89b3a5d96af0
Feng, Zhuo
cd51c72a-9ae9-452d-87ba-62520081e90a
Hewak, Daniel W.
87c80070-c101-4f7a-914f-4cc3131e3db0
Morgan, Katrina
2b9605fc-ac61-4ae7-b5f1-b6e3d257701d
Zeimpekis, Ioannis
a2c354ec-3891-497c-adac-89b3a5d96af0
Feng, Zhuo
cd51c72a-9ae9-452d-87ba-62520081e90a
Hewak, Daniel W.
87c80070-c101-4f7a-914f-4cc3131e3db0

Morgan, Katrina, Zeimpekis, Ioannis, Feng, Zhuo and Hewak, Daniel W. (2022) Enhancing thermoelectric properties of bismuth telluride and germanium telluride thin films for wearable energy harvesting. Thin Solid Films, 741, 1-12, [139015]. (doi:10.1016/j.tsf.2021.139015).

Record type: Article

Abstract

High performance semiconducting thin films enable the implementation of thermoelectric generators as energy harvesters for wearable applications. The optimization of material properties is critical in such applications, as restrictions introduced by the substrates on deposition temperature and active layer size, impose fundamental limitations on performance. Here we present the optimization of sputtered bismuth telluride, BiTe, and germanium telluride, GeTe, annealed at 300 ºC allowing comfortable development on polyimide substrates. The crystal structure and material composition of the films, before and after annealing, were measured by X-ray diffraction and X-ray photoelectron spectroscopy to reveal the changes in the material that enhanced the performance. The power factor of the BiTe films increased post-anneal up to 2.2 μW/cmK2, whilst the GeTe increased over 5 orders of magnitude to 7.6 μW/cmK2. A flexible thermoelectric generator was fabricated with pairs of alternating annealed BiTe and GeTe strips, reaching 7 nW per pair of output power at a temperature difference of 20 °C. Using this micro-fabrication process of thin films, compatible to roll-to-roll technologies, the physical dimensions of the generators can be tuned to deliver the required power, for providing storage energy for on-demand devices such as periodic sensing.

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More information

Accepted/In Press date: 18 November 2021
e-pub ahead of print date: 21 November 2021
Published date: 1 January 2022
Keywords: Bismuth telluride, Flexible thermoelectric generators, Germanium telluride, Post-annealing, Sputtering, Thin film, Wearable technology

Identifiers

Local EPrints ID: 452984
URI: http://eprints.soton.ac.uk/id/eprint/452984
ISSN: 0040-6090
PURE UUID: 25637d0c-4883-4a60-b011-1e423a33b6e7
ORCID for Katrina Morgan: ORCID iD orcid.org/0000-0002-8600-4322
ORCID for Daniel W. Hewak: ORCID iD orcid.org/0000-0002-2093-5773

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Date deposited: 07 Jan 2022 12:10
Last modified: 08 Jan 2022 03:12

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Contributors

Author: Katrina Morgan ORCID iD
Author: Zhuo Feng
Author: Daniel W. Hewak ORCID iD

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