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TiO2/Cu2O/CuO Multi-Nanolayers as Sensors for H2 and Volatile Organic Compounds: An Experimental and Theoretical Investigation

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dc.contributor.author LUPAN, Oleg
dc.contributor.author SANTOS-CARBALLAL, David
dc.contributor.author ABABII, Nicolai
dc.contributor.author MAGARIU, Nicolae
dc.contributor.author HANSEN, Sandra
dc.contributor.author VAHL, Alexander
dc.contributor.author ZIMOCH, Lukas
dc.contributor.author HOPPE, Mathias
dc.contributor.author PAUPORTÉ, Thierry
dc.contributor.author GALSTYAN, Vardan
dc.contributor.author SONTEA, Victor
dc.contributor.author CHOW, Lee
dc.contributor.author FAUPEL, Franz
dc.contributor.author ADELUNG, Rainer
dc.contributor.author de LEEUW, Nora H.
dc.contributor.author COMINI, Elisabetta
dc.date.accessioned 2022-05-06T09:57:08Z
dc.date.available 2022-05-06T09:57:08Z
dc.date.issued 2021
dc.identifier.citation LUPAN, Oleg, SANTOS-CARBALLAL, David, ABABII, Nicolai et al. TiO2/Cu2O/CuO Multi-Nanolayers as Sensors for H2 and Volatile Organic Compounds: An Experimental and Theoretical Investigation. In: ACS Applied Materials & Interfaces, 2021, V. 13, Iss. 27, pp. 32363-32380. ISSN 1944-8244. en_US
dc.identifier.issn 1944-8244
dc.identifier.uri https://doi.org/10.1021/acsami.1c04379
dc.identifier.uri http://repository.utm.md/handle/5014/20235
dc.description Access full text - https://doi.org/10.1021/acsami.1c04379 en_US
dc.description.abstract TiO2/Cu2O/CuO multi-nanolayers highly sensitive toward volatile organic compounds (VOCs) and H2 have been grown in various thicknesses by a cost-effective and reproducible combined spray–sputtering–annealing approach. The ultrathin TiO2 films were deposited by spray pyrolysis on top of sputtered–annealed Cu2O/CuO nanolayers to enhance their gas sensing performance and improve their protection against corrosion at high operating temperatures. The prepared heterostructures were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and ultraviolet visible (UV–vis) and micro-Raman spectroscopy. The gas sensing properties were measured at several operating temperatures, where the nanolayered sensors with oxide thicknesses between 20 and 30 nm (Cu2O/CuO nanolayers) exhibited a high response and an excellent selectivity to ethanol vapor after thermal annealing the samples at 420 °C. The results obtained at an operating temperature of 350 °C demonstrate that the CuO/Cu2O nanolayers with thicknesses between 20 and 30 nm are sensitive mainly to ethanol vapor, with a response of ∼150. The response changes from ethanol vapors to hydrogen gas as the thickness of the CuO/Cu2O nanolayers changes from 50 to 20 nm. Density functional theory-based calculations were carried out for the geometries of the CuO(1̅11)/Cu2O(111) and TiO2(111)/CuO(1̅11)/Cu2O(111) heterostructures and their sensing mechanism toward alcohols of different chain lengths and molecular hydrogen. The reconstructed hexagonal Cu2O(111) surface and the reconstructed monoclinic CuO(1̅11) and TiO2(111) facets, all of which terminate in an O layer, lead to the lowest surface energies for each isolated material. We studied the formation of the binary and ternary heteroepitaxial interfaces for the surface planes with the best-matching lattices. Despite the impact of the Cu2O(111) substrate in lowering the atomic charges of the CuO(1̅11) adlayer in the binary sensor, we found that it is the different surface structures of the CuO(1̅11)/Cu2O(111) and TiO2(111)/CuO(1̅11)/Cu2O(111) devices that are fundamental in driving the change in the sensitivity response observed experimentally. The experimental data, supported by the computational results, are important in understanding the use of the multi-nanolayered films tested in this work as reliable, accurate, and selective sensor structures for the tracking of gases at low concentrations. en_US
dc.language.iso en en_US
dc.publisher American Chemical Society en_US
dc.rights Attribution-NonCommercial-NoDerivs 3.0 United States *
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/3.0/us/ *
dc.subject nanolayers en_US
dc.subject nanomaterials en_US
dc.subject multilayered films en_US
dc.subject films en_US
dc.subject sensors en_US
dc.title TiO2/Cu2O/CuO Multi-Nanolayers as Sensors for H2 and Volatile Organic Compounds: An Experimental and Theoretical Investigation en_US
dc.type Article en_US


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