resumo
Molybdenum oxide thin films were deposited on stiff and flexible substrates by reactive DC magnetron sputtering. Two sets of samples were prepared. The first with different O-2/Ar flow rate ratios and the second, fixing the oxygen content, with different time of deposition. As the O-2/Ar flow rate ratio varies from 0 up to 0.56, a threshold was found, ranging from crystalline to amorphous nature, and from a nontransparent appearance with metallic-like electrical conductivity to transparent and dielectric behaviour. From the second set, all transparent, the MoOx films present a compact/dense and featureless morphology with thickness from 190 up to 910 nm, depending on the time of deposition. Their structure was corroborated by XPS and Rutherford Backscattering Spectrometry (RBS) and density measurements were performed by RBS and X-ray reflectivity (XRR), revealing a value of 2.4 g/cm(3). The surface roughness is in the order of a few nanometers and the maxima optical transmission, in the visible range, is around 89%. Electrochemical cyclic voltammograms showed noticeable color reversibility and reproducibility on the flexible substrates opening new framework possibilities for new electrochomic devices.
categoria
Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter
autores
Marciel, A; Graca, M; Bastos, A; Pereira, L; Kumar, JS; Borges, J; Vaz, F; Peres, M; Magalhaes, S; Lorenz, K; Silva, R
nossos autores
Alice Maria da Costa Marciel Trabulo
Estudante de doutoramento
Ana Rita da Naia Bastos
Investigador
António Alexandre Cunha Bastos
Investigador Júnior
Rui Ramos Ferreira e Silva
Professor associadoGrupos
G1 - Materiais Porosos e Nanossistemas
G3 - Materiais Eletroquímicos, Interfaces e Revestimentos
agradecimentos
This work was partially supported by FEDER funds through the COMPETE 2020 Programme and National Funds through FCTPortuguese Foundation for Science and Technology under the project UID/CTM/50025/2019. It was also developed within the scope of the project CICECOAveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES and by FCT-Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of 29 August, changed by Law 57/2017, of 19 July. This research was also partially funded by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2019 and by the project NANO4BIO, POCI-01-0145-FEDER-032299 and FCT reference PTDC/FIS-MAC/32299/2017. The authors are grateful to the LAS laboratory at CEMUP, for the XPS measurements.