Following with a high sensitivity the adsorption of gases on nanoparticles by indirect nanoplasmonic sensing

International audienceThe indirect nanoplasmonic sensing (INPS) lets us to follow the adsorption of gases on nanoparticles by measuring the shift in wavelength of the localized surface plasmon resonance (LSPR) signal of gold disks on which nanoparticles are deposited. Indeed during the adsorption of gas molecules on nanoparticles the dielectric properties at the surface of the nanoparticles are changed and it generates a shift of the LSPR wavelength of the underlying gold disk detector [1].We describe in this work the different steps of the gold disks fabrication by electron beam lithography, the experimental set-up and present an accurate calibration of our LSPR gold sensor. Then we measure water adsorption isotherms by following the shift of the LSPR wavelength when water molecules adsorb/desorb on the gold disks surface, we were able to detect a few hundredths of an adsorbed water monolayer !We show in a second part some results obtained by INPS on the adsorption/desorption of water on different carbon soot nanoparticles [2].INPS associated to mass spectrometry can also be useful to follow quantitatively and with a high sensitivity the reactivity of gases (CO, NOx, …) with metallic nanoparticles. (e.g. for catalytic reactions).[1] E. M. Larsson, C. Langhammer, I. Zoric, B. Kasemo, Science 326, 1091-1094 (2009)[2] B. Demirdjian, F. Bedu, A. Ranguis, I. Ozerov, A. Karapetyan and C. R. Henry, The Journal of Physical Chemistry Letters 6, 4148-4152 (2015)