Improved versatility of silver nanoparticle dimers for surface-enhanced raman spectroscopy

Iain A. Larmour, Karen Faulds, Duncan Graham

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Single-molecule detection by surface-enhanced (resonance) Raman spectroscopy (SE(R)RS) relies on the production of single "hot spots" formed when metallic nanoparticles couple together to give a region of intense electromagnetic enhancement Creation of aggregates by the addition of electrolytes to screen the Coulombic repulsion energy (V-max) often leads to the formation of large aggregates, resulting in many "hot spots" within the laser probe volume. Controlled electrolyte addition can lower the repulsion to a value 0 < V-max < 15 k(B)T leading to a solution which is enriched in small aggregates but does not show complete, uncontrolled aggregation. An important consideration is choosing an appropriate electrolyte to induce the aggregation, for example chloride anions displace the citrate layer on silver colloids preventing measurement of analytes with a binding affinity to silver more than citrate but less than chloride. Therefore, we have investigated the use of sulfate anions to prepare a colloid solution enriched in small clusters comparable in SE(R)RS activity to that formed with chloride anions. Such a solution will extend the range of analytes that can be investigated by single molecule detection SE(R)RS.

LanguageEnglish
Pages13249-13254
Number of pages6
JournalJournal of Physical Chemistry C
Volume114
Issue number31
DOIs
Publication statusPublished - 12 Aug 2010

Fingerprint

versatility
Silver
Dimers
Electrolytes
Anions
Raman spectroscopy
Chlorides
Negative ions
chlorides
silver
dimers
electrolytes
citrates
Nanoparticles
anions
Colloids
Citric Acid
nanoparticles
colloids
Agglomeration

Keywords

  • scattering sers
  • molecules
  • staistics
  • signals
  • arrays
  • raman spectroscopy
  • dyes

Cite this

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Improved versatility of silver nanoparticle dimers for surface-enhanced raman spectroscopy. / Larmour, Iain A.; Faulds, Karen; Graham, Duncan.

In: Journal of Physical Chemistry C, Vol. 114, No. 31, 12.08.2010, p. 13249-13254.

Research output: Contribution to journalArticle

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