title: Optimization of Nanoparticle-Based SERS Substrates through Large-Scale Realistic Simulations.
abstract: Surface-enhanced Raman scattering (SERS) has become a widely used spectroscopic technique for chemical identification, providing unbeaten sensitivity down to the single-molecule level. The amplification of the optical near field produced by collective electron excitations -plasmons- in nanostructured metal surfaces gives rise to a dramatic increase by many orders of magnitude in the Raman scattering intensities from neighboring molecules. This effect strongly depends on the detailed geometry and composition of the plasmon-supporting metallic structures. However, the search for optimized SERS substrates has largely relied on empirical data, due in part to the complexity of the structures, whose simulation becomes prohibitively demanding. In this work, we use state-of-the-art electromagnetic computation techniques to produce predictive simulations for a wide range of nanoparticle-based SERS substrates, including realistic configurations consisting of random arrangements of hundreds of nanoparticles with various morphologies. This allows us to derive rules of thumb for the influence of particle anisotropy and substrate coverage on the obtained SERS enhancement and optimum spectral ranges of operation. Our results provide a solid background to understand and design optimized SERS substrates.
authors.affiliation: Departamento de Teoría de la Señal y Comunicaciones, University of Vigo , 36301 Vigo, Spain.
authors.forename: Diego M
authors.initials: DM
authors.lastname: Solís
authors.affiliation: Departamento de Tecnología de Computadores y Comunicaciones, University of Extremadura , 10003 Cáceres, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Taboada
authors.affiliation: Departamento de Teoría de la Señal y Comunicaciones, University of Vigo , 36301 Vigo, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Obelleiro
authors.affiliation: Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20014 Donostia-San Sebastian, Spain; Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain; CIBER de Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN, 20014 Donostia-San Sebastian, Spain.
authors.forename: Luis M
authors.initials: LM
authors.lastname: Liz-Marzán
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain; ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain.
authors.forename: F Javier
authors.initials: FJ
authors.lastname: García de Abajo
keywords: gold nanoparticles; optical sensing; particle arrays; plasmons; surface-enhanced Raman scattering (SERS)