Influence of copper telluride nanodomains on the transport properties of n-type bismuth telluride
The high processing cost, poor mechanical properties and moderate performance of BiTe-based alloys used in thermoelectric devices limit the cost-effectiveness of this energy conversion technology. Towards solving these current challenges, in the present work, we detail a low temperature solution-bas...
| Autores: | , , , , , , , , , , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2021 |
| País: | España |
| Institución: | Universitat Autònoma de Barcelona |
| Repositorio: | Dipòsit Digital de Documents de la UAB |
| Idioma: | inglés |
| OAI Identifier: | oai:ddd.uab.cat:271949 |
| Acceso en línea: | https://ddd.uab.cat/record/271949 https://dx.doi.org/urn:doi:10.1016/j.cej.2021.129374 |
| Access Level: | acceso abierto |
| Palabra clave: | Bi2Te3 Nanocomposites Energy filtering effect Cu2-xTe Thermoelectricity |
| Sumario: | The high processing cost, poor mechanical properties and moderate performance of BiTe-based alloys used in thermoelectric devices limit the cost-effectiveness of this energy conversion technology. Towards solving these current challenges, in the present work, we detail a low temperature solution-based approach to produce BiTe-CuTe nanocomposites with improved thermoelectric performance. Our approach consists in combining proper ratios of colloidal nanoparticles and to consolidate the resulting mixture into nanocomposites using a hot press. The transport properties of the nanocomposites are characterized and compared with those of pure BiTe nanomaterials obtained following the same procedure. In contrast with most previous works, the presence of CuTe nanodomains does not result in a significant reduction of the lattice thermal conductivity of the reference BiTe nanomaterial, which is already very low. However, the introduction of CuTe yields a nearly threefold increase of the power factor associated to a simultaneous increase of the Seebeck coefficient and electrical conductivity at temperatures above 400 K. Taking into account the band alignment of the two materials, we rationalize this increase by considering that CuTe nanostructures, with a relatively low electron affinity, are able to inject electrons into BiTe, enhancing in this way its electrical conductivity. The simultaneous increase of the Seebeck coefficient is related to the energy filtering of charge carriers at energy barriers within BiTe domains associated with the accumulation of electrons in regions nearby a CuTe/BiTe heterojunction. Overall, with the incorporation of a proper amount of CuTe nanoparticles, we demonstrate a 250% improvement of the thermoelectric figure of merit of Bi2Te3. |
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