Optimization of nanocomposite Au/TiO 2  thin films towards LSPR optical-sensing

Rodrigues, Marco S.; Costa, Diogo; Domingues, R. P.; Apreutesei, M.; Pedrosa, Paulo; Martin, Nicolas; Correlo, Vítor M.; Reis, Rui L.; Alves, E.; Barradas, N.P.; Sampaio, Paula; Borges, Joel Nuno Pinto; Vaz, F.

doi:10.1016/j.apsusc.2017.09.162

Cited by 60 publications

(60 citation statements)

References 42 publications

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“…The formed columns are titled toward the incident flux direction and can be sculptured into different morphologies, such as helices, inclined and vertical pillars (with variable diameter), zig-zags, and square spirals [49][50][51][52][53]. All these efforts make the GLAD technique excellent for design and device optimization for the development of sensors and optical devices, among others [45,[54][55][56][57][58].…”

Section: Introductionmentioning

confidence: 99%

Antifungal activity of ZnO thin films prepared by glancing angle deposition

et al. 2019

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Highlights• Zinc Oxide thin films were deposited by reactive magnetron sputtering;• Inclined columns changed the thin films' surface porosity;• Sputtering incidence angle affects microstructure and antifungal properties;• Mesoporous thin films improved the antifungal properties against Candida albicans; ABSTRACTThin films of zinc oxide (ZnO) were produced by reactive DC magnetron sputtering with sputtering angles of α = 0º, 40º, 60º and 80º (glancing angle deposition configuration), aiming to be tested against the opportunist pathogenic fungus Candida albicans. The results showed the formation of stoichiometric ZnO thin films, with inclined columns for incidence angles equal to or more than 40º. All thin films presented high transparency in the visible range above the bandgap region (near 380 nm). The deposition conditions gave rise to a three-fold increase of the surface porosity with the increment of the incidence angle. Noteworthy, is the formation of different types of pores distributions, from micro-, through meso-, to macropores. Regarding the biological effect, the thin films produced with inclined columns presented a significant antifungal activity, with the inhibition of viable cell growth by 68 %. Moreover, the formation of mesoporous films enhanced the antifungal properties of ZnO thin films against Candida albicans. The overall behaviour indicates that these thin films are promising candidates to be applied in antimicrobial surfaces, as well as to be used in further studies to determine the molecular mechanisms involved in the antimicrobial action of ZnO.3

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Section: Introductionmentioning

confidence: 99%

Antifungal activity of ZnO thin films prepared by glancing angle deposition

et al. 2019

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“…RBS analysis showed that there was a higher gold content in the Al2O3 matrix, comparing to the TiO2 matrix, for the same amount of gold in the target (two pellets). This could be due to the difference in the applied current to the sputtering target, as previously shown, a higher current causes a lower effective Au sputtered area [50], and also the lower sputtering yield of Al2O3 compared to TiO2 [55]. Changing the noble metal into the TiO2 matrix from Au to Ag displayed different noble metal concentrations in the thin films.…”

Section: Composition and Microstructure Of The As-deposited Filmsmentioning

confidence: 83%

“…Plasma treatment was performed in all samples at 700 °C annealing to increase the number of nanoparticles partially exposed to the surface, as showed by Rodrigues et al [50].…”

Section: Raman Measurements In Plasmonic Thin Filmsmentioning

confidence: 99%

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Development of biocompatible plasmonic thin films composed of noble metal nanoparticles embedded in a dielectric matrix to enhance Raman signals

Costa

Oliveira

Rodrigues

et al. 2019

Applied Surface Science

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This work focused on the production of nanocomposite thin films, composed of noble nanoparticles embedded in a dielectric matrix, to be tested as biocompatible plasmonic platforms for detection of molecules using Surface Enhance Raman Spectroscopy (SERS). Three different thin films systems were deposited by reactive DC magnetron sputtering, namely Au-Al2O3, Au-TiO2 and Ag-TiO2. The depositions were followed by a thermal treatment at different temperatures to promote the growth of the nanoparticles. Localized Surface Plasmon Resonance (LSPR) bands appeared already at 300 ºC, related to the presence of Au nanoparticles, and at 500 ºC in the case of Ag nanoparticles. Furthermore, at 700º C, the Ag-TiO2 films showed a broadband optical response due to the formation of Ag clusters at the film's surface. The biological experiments showed that the presence of the thin films didn't affect the growth of C. albicans, which is very convenient if one needs to detect low concentrations of this microorganism using SERS platforms. As for the SERS 2 measurements, an enhancement of R6G Raman spectra intensity was clearly perceivable, but only for the TiO2 matrix. Furthermore, the application of a plasma treatment allowed to better expose the nanoparticles, providing a further enhancement of Raman signals.

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“…To avoid damaging the polymer substrates, the deposition parameters were adjusted relatively to what was reported in [41], applying a constant current density of 75 A/m 2 in the target for a duration of 9 min. Furthermore, the total area of pellets used was 32 mm 2 , taking into account previous results [56]. The target potential stabilized at about 364 (-V) within the first few seconds.…”

Section: Methodsmentioning

confidence: 99%

Preparation of Plasmonic Au-TiO2 Thin Films on a Transparent Polymer Substrate

et al. 2020

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In this work, plasmonic thin films composed of Au nanoparticles embedded in a TiO2 matrix were prepared in a transparent polymer substrate of poly(dimethylsiloxane) (PDMS). The thin films were deposited by reactive DC magnetron sputtering, and then subjected to heat treatment up to 150 °C in order to promote the growth of the Au nanoparticles throughout the TiO2 matrix. The transmittance spectrum of the thin films was monitored in situ during the heat treatment, and the minimum time required to have a defined localized surface plasmon resonance (LSPR) band was about 10 min. The average size of Au nanoparticles was estimated to be about 21 nm—the majority of them are sized in the range 10–40 nm, but also extend to larger sizes, with irregular shapes. The refractive index sensitivity of the films was estimated by using two test fluids (H2O and DMSO), and the average value reached in the assays was 37.3 ± 1.5 nm/RIU, resulting from an average shift of 5.4 ± 0.2 nm. The results show that it is possible to produce sensitive plasmonic Au-TiO2 thin films in transparent polymer substrates such as PDMS, the base material to develop microfluidic channels to be incorporated in LSPR sensing systems.

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Optimization of nanocomposite Au/TiO 2 thin films towards LSPR optical-sensing

Cited by 60 publications

References 42 publications

Antifungal activity of ZnO thin films prepared by glancing angle deposition

Antifungal activity of ZnO thin films prepared by glancing angle deposition

Development of biocompatible plasmonic thin films composed of noble metal nanoparticles embedded in a dielectric matrix to enhance Raman signals

Preparation of Plasmonic Au-TiO2 Thin Films on a Transparent Polymer Substrate

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