Optical response and SERS properties of individual large scale supracrystals made of small silver nanocrystals
Résumé
There is a considerable interest in producing and understanding the optical and
spectroscopic properties of ordered nanoparticle assemblies. Herein, we describe
and interpret the optical absorbance and Raman properties of 5.9 nm ± 0.3 nm
diameter silver nanocrystals coated with dodecanethiol and organized in highly
ordered 3D superlattices of different heights. Each superlattice was studied
individually, which allowed to elaborate a model based on Maxwell-Garnett
theory to reproduce qualitatively the height and wavelength dependence of
the absorbance. Importantly, because of their small size compared to that of
traditional nanoparticles used in Surface Enhanced Raman Spectroscopy (SERS),
the large 3D distribution of hot spots generated by the silver superlattices
allowed to easily obtain SERS spectra of the surrounding ligands despite their
intrinsic low Raman cross section. Accordingly, traces of thiophenol could be
detected very easily.
Origine : Fichiers produits par l'(les) auteur(s)
Loading...