Grupo de Nanofotonica

Permanent URI for this collectionhttp://48.217.138.120/handle/20.500.12272/1241

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Subject: search.filters.subject.Plasmonics

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Now showing 1 - 5 of 5
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    Kinetic and plasmonic properties of gold nanorods adsorbed on glass substrates
    (2019-10-24) Gutiérrez, Marina V.; Scarpettini, Alberto Franco
    Monodisperse gold nanorods with different sizes were synthesized and adsorbed on chemically modified glass substrates. Influence of surfactant molar concentration on nanorod adsorption was studied and the optimum range was determined. During substrate coverages we monitored the growth of longitudinal localized surface plasmon resonances at short times due to density increase of isolated nanorods and, at longer times, their subsequent decrease and a concurrent growth of coupling resonances owing to nanoparticle surface mobility and aggregation. Temporal evolution of amplitudes of resonance peaks in extinction spectra and nanorod counting statistics in electron micrographs were used to model both coverage and aggregation processes, as exponentiallike functions of time. Their characteristic times and saturation values were analyzed and related to kinetic parameters, nanorod dimensions and extinction coefficients. This work can be used as a predictive tool to prepare plasmonic substrates with desired optical resonances.
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    Determination of nanoscale mechanical properties of polymers via plasmonic nanoantennas
    (2020-06-02) Boggiano, Hilario D.; Berté, Rodrigo; Cortés, Emiliano; Maier, Stefan A.; Bragas, Andrea V.; Scarpettini, Alberto Franco
    Nanotechnology and the consequent emergence of miniaturized devices are driving the need to improve our understanding of the mechanical properties of a myriad of materials. Here we focus on amorphous polymeric materials and introduce a new way to determine the nanoscale mechanical response of polymeric thin films in the GHz range, using ultrafast optical means. Coupling of the films to plasmonic nanoantennas excited at their vibrational eigenfrequencies allows the extraction of the values of the mechanical moduli as well as the estimation of the glass transition temperature via time-domain measurements, here demonstrated for PMMA films. This nanoscale method can be extended to the determination of mechanical and elastic properties of a wide range of spatially strongly confined materials.
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    Challenges on optical printing of colloidal nanoparticles.
    (2022-01-18) Violi, Ianina L.; Martínez, Luciana P.; Barella, Mariano; Zaza, Cecilia; Chvátal, Lukás; Zemánek, Pavel; Gutiérrez, Marina V.; Paredes, María Yanela; Scarpettini, Alberto Franco; Olmos-Trigo, Jorge; Pais, Valeria R.; Díaz Nóblega, Iván; Cortés, Emiliano; Sáenz, Juan José; Bragas, Andrea V.; Gargiulo, Julián; Stefani, Fernando D.
    While colloidal chemistry provides ways to obtain a great variety of nanoparticles with different shapes, sizes, material compositions, and surface functions, their controlled deposition and combination on arbitrary positions of substrates remain a considerable challenge. Over the last ten years, optical printing arose as a versatile method to achieve this purpose for different kinds of nanoparticles. In this article, we review the state of the art of optical printing of single nanoparticles and discuss its strengths, limitations, and future perspectives by focusing on four main challenges: printing accuracy, resolution, selectivity, and nanoparticle photostability.
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    Efficient method of arsenic removal from water based on photocatalytic oxidation by a plasmonic–magnetic nanosystem
    (2022-12-13) Paredes, María Yanela; Martínez, Luciana P.; Barja, Beatriz C.; Marchi, M. Claudia; Herran, Matías; Grinblat, Gustavo; Bragas, Andrea V.; Cortés, Emiliano; Scarpettini, Alberto F.
    Arsenic is one of the most toxic elements in natural waters since prolonged exposure to this metalloid can cause chronic damage to health. Its removal from ground-water remains one of the greatest environmental challenges to be addressed nowadays. Here, we present core-satellite hybrid nanostructures formed by plasmonic gold satellites supported onto magnetic iron oxides cores for sunlight-driven remediation of arsenic-containing water. Our experimental results show that the gold nanoparticles catalyze the oxidation of arsenic to much less toxic species and that - upon illumination - the generated heat and hot carriers further enhance the reaction rate. The iron oxides act as an arsenic adsorbent, enabling the complete removal of the catalysts and the adsorbed oxidized arsenic species through a magnet. We quantified the different catalytic contributions, showing that the plasmonic one is of the same order as the surface one. This work highlights the synergy between plasmonic catalysts and iron oxides for light-assisted water remediation.
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    Kinetic and plasmonic properties of gold nanorods adsorbed on glass substrates
    (2019-09-19) Gutierrez, Marina; Scarpettini, Alberto F
    Monodisperse gold nanorods with different sizes were synthesized and adsorbed on chemically modified glass substrates. Influence of surfactant molar concentration on nanorod adsorption was studied and the optimum range was determined. During substrate coverages we monitored the growth of longitudinal localized Surface plasmon resonances at short times due to density increase of isolated nanorods and, at longer times, their subsequent decrease and a concurrent growth of coupling resonances owing to nanoparticle surface mobility andaggregation. Temporal evolution of amplitudes of resonance peaks in extinction spectra and nanorod counting statistics in electron micrographs were used to model both coverage and aggregation processes, as exponential- like functions of time. Their characteristic times and saturation values were analyzed and related to kinetic parameters, nanorod dimensions and extinction coefficients. This work can be used as a predictive tool to prepare plasmonic substrates with desired optical resonances.