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Structural and optical studies of Au doped titanium oxide films
Alves, E.; Franco, N.; Barradas, N. P.; Nunes, B.; Lopes, J.; Cavaleiro, A.; Torrell, M.; Cunha, L.; Vaz, F.Thin films of TiO2 were doped with Au by ion implantation and in situ during the deposition. The films were grown by reactive magnetron sputtering and deposited in silicon and glass substrates at a temperature around 150 °C. The undoped films were implanted with Au fluences in the range of 5 × 1015 Au/cm2–1 × 1017 Au/cm2 with a energy of 150 keV. At a fluence of 5 × 1016 Au/cm2 the formation of Au nanoclusters ...
Treatment of cotton with an alkaline Bacillus spp cellulase : activity towards ...
Caparrós Vásquez, Cristina Maria; López, C.; Torrell, M.; Lant, Neil; Smets, Johan; Paulo, Artur CavacoWe analysed the influence of several enzymatic treatment processes using an alkaline cellulase enzyme from Bacillus spp. on the sorption properties of cotton fabrics. Although cellulases are commonly applied in detergent formulations due to their anti-redeposition and depilling benefits, determining the mechanism of action of alkaline cellulases on cotton fibres requires a deeper understanding of the morphology...
Tuning of the surface plasmon resonance in TiO2/Au thin films grown by magnetro...
Torrell, M.; Kabir, R.; Cunha, L.; Vasilevskiy, Mikhail; Vaz, F.; Cavaleiro, A.; Alves, E.; Barradas, N. P.Nanocomposites consisting of a dielectric matrix, such as TiO2, with embedded noble metal nanoparticles (NPs) possess specific optical properties due to the surface plasmon resonance (SPR) effect, interesting for several applications. The aim of this work is to demonstrate that these properties are sensitive to the nanostructure of magnetron-sputtered TiO2/Au thin films, which can be tuned by annealing. We stud...
Structural and optical properties of Ag : TiO2 nanocomposite films prepared by ...
Adochite, R.; Torrell, M.; Cunha, L.; Alves, E.; Barradas, N. P.; Cavaleiro, A.; Rivière, J. P.; Eyidi, D.; Vaz, F.Three sets of nanocomposite films consisting of different atomic concentrations of Ag dispersed in a TiO2 dielectric matrix were deposited by DC reactive magnetron sputtering, and subjected to several thermal annealing experiments in vacuum, for temperatures ranging from 200 to 600 ºC. The main goal of the present study is to analyse the optical properties of the as-deposited and annealed films in order to clar...
Nanoscale color control of TiO2 films with embedded Au nanoparticles
Torrell, M.; Cunha, L.; Kabir, R.; Cavaleiro, A.; Vasilevskiy, Mikhail; Vaz, F.Article in press ; We demonstrate an efficient nanoscale control of the optical properties of TiO2 films by tuning the Surface Plasmon Resonance (SPR) in the embedded Au nanoparticles. The films were grown by reactive magnetron sputtering. SPR tuning was achieved by different annealings, which affected the shape and size of the Au nanoparticles, and also the phase of the dielectric matrix. These changes promot...
Functional and optical properties of Au :TiO2 nanocomposite films : the influen...
Torrell, M.; Cunha, L.; Cavaleiro, A.; Alves, E.; Barradas, N. P.; Vaz, F.A set of nanocomposite thin films consisting of Au nanoclusters dispersed in a TiO2 dielectric matrix was deposited by reactive magnetron sputtering, and subjected to thermal annealing in vacuum, at temperatures ranging from 200 to 800 ◦C. The obtained results show that the structure and the size of Au clusters, together with the matrix crystallinity, changed as a result of the annealing, and were shown to be a...
Development of new decorative coatings based on gold nanoparticles dispersed in...
Torrell, M.; Machado, P.; Cunha, L.; Figueiredo, N. M.; Oliveira, J. C.; Louro, C.; Vaz, F.The present work is devoted to the optical properties of Au:TiO2 thin films in order to clarify the role of the Au clusters inclusions in the TiO2 dielectric matrix. Three series of films containing about 30 at.% (29.2), 20 at. % (19.8) and 10 at.% (9.3) Au were deposited by dc reactive magnetron sputtering. On thermal annealing in the range from 300 to 800 °C in protective atmosphere, significant changes on th...
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