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

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 exper

SUBMITTER: Cortijo-Campos S 

PROVIDER: S-EPMC7116317 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature