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Titre du document / Document title

SERS enhancement by aggregated Au colloids: effect of particle size

Auteur(s) / Author(s)

BELL Steven E. J. (1) ; MCCOURT Maighread R. (1) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Innovative Molecular Materials Group, School of Chemistry and Chemical Engineering, Queen's University, Belfast, BT9 5AG, ROYAUME-UNI

Résumé / Abstract

Aggregated Au colloids have been widely used as SERS enhancing media for many years but to date there has been no systematic investigation of the effect of the particle size on the enhancements given by simple aggregated Au colloid solutions. Previous systematic studies on isolated particles in solution or multiple particles deposited onto surfaces reported widely different optimum particle sizes for the same excitation wavelength and also disagreed on the extent to which surface plasmon absorption spectra were a good predictor of enhancement factors. In this work the spectroscopic properties of a range of samples of monodisperse Au colloids with diameters ranging from 21 to 146 nm have been investigated in solution. The UV/visible absorption spectra of the colloids show complex changes as a function of aggregating salt (MgSO4) concentration which diminish when the colloid is fully aggregated. Under these conditions, the relative SERS enhancements provided by the variously sized colloids vary very significantly across the size range. The largest signals in the raw data are observed for 46 nm colloids but correction for the total surface area available to generate enhancement shows that particles with 74 nm diameter give the largest enhancement per unit surface area. The observed enhancements do not correlate with absorbance at the excitation wavelength but the large differences between differently sized colloids demonstrate that even in the randomly aggregated particle assemblies studied here, inhomogeneous broadening does not mask the underlying changes due to differences in particle diameter.

Revue / Journal Title

PCCP. Physical chemistry chemical physics    ISSN  1463-9076 

Source / Source

2009, vol. 11, no 34 (165 p.)  [Document : 8 p.] (bibl.: dissem.), pp. 7455-7462 [8 page(s) (article)]

Langue / Language

Anglais

Editeur / Publisher

Royal Society of Chemistry, Cambridge, ROYAUME-UNI  (1999) (Revue)

Mots-clés anglais / English Keywords

Absorbance

;

Surface area

;

Complexes

;

Ultraviolet visible spectrum

;

Diameter

;

Monodispersed particle

;

Enhancement factor

;

Absorption spectrum

;

Surface plasmon

;

Wavelength

;

Excitation

;

Colloid

;

Surface Enhanced Raman Spectrometry

;

Particle size

;

Colloid particle

;

Mots-clés français / French Keywords

Absorbance

;

Aire superficielle

;

Complexe

;

Spectre UV visible

;

Diamètre

;

Particule monodispersée

;

Facteur accroissement

;

Spectre absorption

;

Plasmon surface

;

Longueur onde

;

Excitation

;

Colloïde

;

Spectrométrie SERS

;

Dimension particule

;

Particule colloïdale

;

Mots-clés espagnols / Spanish Keywords

Absorbancia

;

Area superficial

;

Complejo

;

Espectro UV visible

;

Diámetro

;

Partícula monodispersada

;

Factor incremento

;

Espectro de absorción

;

Plasmón superficie

;

Longitud onda

;

Excitación

;

Coloide

;

Espectrometría SERS

;

Dimensión partícula

;

Partícula coloidal

;

Localisation / Location

INIST-CNRS, Cote INIST : 26801, 35400017106270.0150

Nº notice refdoc (ud4) : 22002403



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