Role of phase separation in nanocomposite indium-tin-oxide films for transparent thermoelectric applications
| Autor: | Vedran Jovic, Kevin E. Smith, Peter P. Murmu, Takao Mori, Shen V. Chong, Zihang Liu, Dana Goodacre, Akhil Shettigar, John Kennedy |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Materials science
Indium-tin-oxide (ITO) Analytical chemistry chemistry.chemical_element 02 engineering and technology 010402 general chemistry 01 natural sciences Oxygen X-ray photoelectron spectroscopy Seebeck coefficient Thermoelectric effect lcsh:TA401-492 Nanocomposite Thermoelectric Metals and Alloys X-ray photoelectron spectroscopy (XPS) Partial pressure 021001 nanoscience & nanotechnology Thermoelectric materials 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Indium tin oxide chemistry Power factor lcsh:Materials of engineering and construction. Mechanics of materials 0210 nano-technology |
| Zdroj: | Journal of Materiomics, Vol 7, Iss 3, Pp 612-620 (2021) |
| ISSN: | 2352-8478 |
| Popis: | We report that oxygen vacancies have a profound impact on phase separation and thermoelectric properties of ITO films grown at room temperature. Oxygen vacancies in non-stoichiometric In1.8Sn0.2O2.5 films aided the formation of In-rich metallic clusters. It yields a high electrical conductivity σ = 1540 Scm−1 and Seebeck coefficient |α| = 27.2 μVK−1, which resulted in the highest power factor (α2σ = 113.8 μW m−1K−2) but low optical transmission (Top ∼ 25%). An increase in oxygen partial pressure resulted in stochiometric In1.8Sn0.2O3 films which improved the optical transparency by 300% (Top ∼75.4%), but power factor was reduced by ∼85% due to a decrease in α and σ. A decrease in α was due to the lack of energy filtering of charge carriers in the stoichiometric ITO film which did not have In-rich metallic clusters. XPS results showed that the valence band energy shifts with a change in oxygen partial pressure due to a decrease in carrier density, which implied a change in Fermi energy due to the reverse Moss-Burstein effect. Our results showed that phase separation can be obtained in nanocomposite ITO films by tuning their stoichiometry simply by varying the oxygen partial pressure during deposition of thermoelectric materials at low temperatures. |
| Databáze: | OpenAIRE |
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