Centre d’Élaboration de Matériaux et d’Etudes Structurales (UPR 8011)


Accueil > Recherche > NeO : Nano-Optique et Nanomatériaux pour l’Optique > Nanoparticules dans les diélectriques

Presentation


Permanent researchers : C. Bonafos, M. Carrada, R. Carles, A. Mlayah, V. Paillard (NeO group), G. Benassayag (MEM group), B. Pecassou (nanofabrication service)
PhD students : A. Pugliara (2012-2016), A. Haj Salem (2012-2016)

Initially restricted to semiconducting (Si) nanocrystals embedded in silica for opto-electronic and nano-electronic applications, this thematic has been recently extended to the synthesis of metallic nanoparticles (AgNPs) embedded in dielectrics for plasmonics applications, third generation solar cells and bactericide coatings. These nanocomposites are elaborated by a physical route, Low Energy Ion Beam Synthesis (LE-IBS)[1]. By forming 2D arrays (planes) the nanoparticles can be inserted in very thin layers and localised at nanometric distances from the dielectric surface. The dielectric matrix (silica, silicon nitride) protects the particles from aging (oxidation) and maintains the surface planarity[2]. This technique allows a tri-dimensional control of these systems : in addition to a fine tuning of the nanoparticle plane position, an organisation in the plane of the nanoparticles can be obtained by implanting through stencil masks. Self-organisation in the plane can also be observed[3]. The fundamental optical or vibrational properties of these plasmonic nanostructures are studied by elastic (reflectivity) or inelastic (Raman-Brillouin) scattering spectroscopies and are correlated to theoretical models.

These metallic nanoparticles embedded in dielectrics are multifunctional objects that can be used at the same time as plasmonic antenna, electron or ion reservoir. The originality of our approach consists in coupling them and/or promoting transfers with objects deposited on top of the dielectric surface (other nanoparticles, molecules, 2D layers…) or with the matrix itself. Applicative projects of embedded nanoplasmonics architectures at the vicinity of a free and flat surface, concern electron-hole generation for photocatalysis or water purification, high contrast imaging and spectroscopy for the understanding of charge tunnelling between nano-objects, prevention of biofilm development, enhanced spectroscopies mechanisms, analysis and control of biocide activity of metallic NPs and/or ions for “safe by design” antibacterial coatings[4].

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(a) Cross-sectional and (b) plan-view Transmission Electron Microscopy Bright Field images of a silica layer implanted with Ag+ at 10 keV with a dose of 7.15x1015 ions/cm2 describing the typical architecture of the samples. (c) HREM image of an isolated nanoparticle.
© CEMES-CNRS

[1] Controlled synthesis of buried delta-layers of Ag nanocrystals for near-field plasmonic effects on free surfaces, P. Benzo, C. Bonafos, M. Bayle, R. Carles, L. Cattaneo, C. Farcau, G.Benassayag, B.Pecassou and D. Muller, Journal of Applied Physics, 113, 193505 (2013).

[2] Stability of Ag nanocrystals synthesized by ultra-low energy ion implantation in SiO2 matrices, P Benzo et al., Journal of Applied Physics, 109, 103524 (2011)

[3] Ag doped silicon nitride nanocomposites for embedded plasmonics, M. Bayle, et al. Applied Physics Letters, 107 (10), 101907 (2015)

[4] Assessing bio-available silver released from silver nanoparticles embedded in silica layers using the green algae Chlamydomonas reinhardtii as bio-sensors, A. Pugliara et al., Science of the total environment, 565, 863-871 (2016).

Keywords :

- Nanocomposites, functional nanomaterials

- Synthesis of nanoparticles by physical routes

- Plasmonics

- Near-field coupling, electron and ion transfer at the nanoscale

- Biocide coatings, photovoltaics