Jérémie Margueritat, iLM, UMR5306 UCBL-CNRS, Villeurbanne, France

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Jérémie Margueritat, iLM, UMR5306 UCBL-CNRS, Villeurbanne, France

Acoustic vibrations of nano-objects for sensing applications.

Jeudi 27/10/16 à 14h salle pierre coton.

Abstract :

One of the technological challenges of these last years is the development highly efficient nano-sensing device, to determine for example the size, the mass, or even the presence or not of a given molecule. An interesting route to develop such sensors is to use the mechanical properties of mechanical nano-resonators, whose high frequencies of vibration (GHz to THz) are ideal to develop nano-clocks or nano-balances. The simplest nano-resonator, and maybe the easiest to produce, is the nanoparticle in which the vibration frequency is directly proportional to its reciprocal dimensions (inverse diameter for a sphere, inverse length for a wire, or inverse thickness for a nanoplatelet).
After a short presentation of the origin of the acoustic vibration of a nano-object, I will present two specific cases, to show that these simple nano-objects have promising potential to develop nano-sensing devices.
The first system studied is a dimer of gold nanoparticles whose ultra low frequency vibration modes (<5GHz 0.15 cm-1) arising from the hybridization of the individual vibration modes of each nanoparticle, is highly sensitive to the elastic properties of the surrounding medium.1
The second system consists of nano-platelets of semi-conductor whose thicknesses can be controlled from 2 to 14 monolayers. Detecting the resonant breathing frequency across the thickness of the nano-platelets reveals a significant sensitivity to mass loads attached to the free surfaces of the nano-platelets.2

1. Girard, A. et al. Mechanical coupling in gold nanoparticles super-molecules
revealed by plasmon-enhanced ultra low frequency Raman spectroscopy. Nano
Lett. 34, acs.nanolett.6b01314 (2016).
2. Girard, A. et al. Mass load effect on the resonant acoustic frequencies of colloidal
semiconductor nanoplatelets. to be published in Nanoscale