Raman amplification in the ultra-small limit of Ag nanoparticles on SiO2 and graphene: Size and inter-particle distance effects release_4d6alwhjrbdeddrctz5foj5rzu

by Sandra Cortijo-Campos, Rafael Ramírez-Jiménez, Esteban Climent-Pascual, Montserrat Aguilar-Pujol, Félix Jiménez-Villacorta, Lidia Martínez, Rafael Jiménez-Riobóo, Carlos Prieto, Alicia de Andrés

Published in Materials & design by Elsevier BV.

2020   Volume 192, p108702

Abstract

Size, shape and hot spots are crucial to optimize Raman amplification from metallic nanoparticle (NPs). The amplification from radius = 1.8 ± 0.4 nm ultra-small silver NPs was explored. Increasing NP density redshifts and widens their plasmon that, according to simulations for NPs arrays, is originated by the reduction of the interparticle distance, d, becoming remarkable for d ≤ R. Inter-particle interaction red-shifts (N130 nm) and widens (N90 nm) the standard plasmon of non-interacting spherical particles. Graphene partly delocalizes the carriers enhancing the NIR spectral weight. Raman amplification of graphene phonons is moderate and depends smoothly on d while that of Rhodamine 6G (R6G) varies almost exponentially due to their location at hotspots that depend strongly on d. The experimental correlation between amplification and plasmon position is well reproduced by simulations. The amplification originated by the ultra-small NPs is compared to that of larger particles, granular silver films with 7 < R < 15 nm grains, with similar extinction values. The amplification is found to be larger for the 1.8nm NPs due to the higher surface/volume ration that allows higher density of hot spots. It is demonstrated that Raman amplification can be efficiently increased by depositing low density layers of ultra-small NPs on top of granular films.
In text/plain format

Archived Files and Locations

application/pdf  1.9 MB
file_hfn64br24zf2velpbzlmwltd44
pdf.sciencedirectassets.com (publisher)
web.archive.org (webarchive)
Read Archived PDF
Preserved and Accessible
Type  article-journal
Stage   published
Date   2020-04-02
Language   en ?
Container Metadata
Open Access Publication
In DOAJ
In Keepers Registry
ISSN-L:  0264-1275
Work Entity
access all versions, variants, and formats of this works (eg, pre-prints)
Catalog Record
Revision: bc740b10-37b1-4de4-8e91-34fc4bb6aa35
API URL: JSON