title: Graphene-mediated surface enhanced Raman scattering in silica mesoporous nanocomposite films.
abstract: Silica mesoporous nanocomposite films containing graphene nanosheets and gold nanoparticles have been prepared via a one-pot synthesis using silicon tetrachloride, gold(III) chloride tetrahydrate, a 1-N-vinyl-2-pyrrolidone dispersion of exfoliated graphene and Pluronic F127 as a structuring agent. The composite films have shown graphene-mediated surface-enhanced Raman scattering (G-SERS). Graphene has been introduced as dispersed bilayer sheets while gold has been thermally reduced in situ to form nanoparticles of around 6 nm which preferentially nucleate on the surface of the graphene nanosheets. The presence of graphene and gold nanoparticles does not interfere with the self-assembly process and the formation of silica mesoporous films ordered as 2D hexagonal structures. The material has shown a remarkable analytical enhancement factor ranging from 80 up to 136 using rhodamine 6G as a Raman probe. The films have been characterised by grazing incidence X-ray diffraction, FTIR and UV-vis spectroscopy studies; transmission electron microscopy and spectroscopic ellipsometry have been used to study the morphology, thickness and porosities of the samples. Raman spectroscopy has been employed to characterise the graphene nanosheets embedded into the mesoporous films and the enhanced Raman scattering.
authors.affiliation: Laboratorio di Scienza dei Materiali e Nanotecnologie, CR-INSTM, DADU, Università di Sassari, Palazzo Pou Salid, Piazza Duomo 6, 07041 Alghero (SS), Italy. plinio@uniss.it.
authors.forename: Davide
authors.initials: D
authors.lastname: Carboni
authors.forename: Barbara
authors.initials: B
authors.lastname: Lasio
authors.forename: Valeria
authors.initials: V
authors.lastname: Alzari
authors.forename: Alberto
authors.initials: A
authors.lastname: Mariani
authors.forename: Danilo
authors.initials: D
authors.lastname: Loche
authors.forename: Maria F
authors.initials: MF
authors.lastname: Casula
authors.forename: Luca
authors.initials: L
authors.lastname: Malfatti
authors.forename: Plinio
authors.initials: P
authors.lastname: Innocenzi
mesh_terms: D006108:Graphite / Q000737:chemistry*; D010316:Particle Size; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D013499:Surface Properties
chemical_list: D012822:Silicon Dioxide; D006108:Graphite