Size-Dependent Shifts of Plasmon Resonance in Silver Nanoparticle Films Using Controlled Dissolution: Monitoring the Onset of Surface Screening Effects

Klaus Bo Mogensen, Katrin Kneipp

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

A study of the size dependent blue- and red-shift of the plasmon band of silver nanoparticle films in aqueous solution is reported. A detection scheme, where the particle size is continuously decreased by means of controlled dissolution, while measuring the plasmon band position by UV–vis absorption spectroscopy is used. Both blue- and red-shifts of the peak position are observed, depending on the presence of electron donors and/or acceptors in the solution, respectively. A great increase in plasmon shifts for smaller particle sizes (R < 5 nm vs R > 10 nm) is demonstrated, which we ascribe to a transition from an extrinsic regime for the larger particles, where shifts of the plasmon frequency are related to changes in the dielectric environment, while the dielectric function of the metal is constant, to an intrinsic regime for the smaller particles. For this intrinsic regime, operative for small particles, nonlocality of the dielectric constant has to be considered. The experimental data are fitted with a recently published theoretical model that takes dynamical surface screening and quantum size effects into account as well as by a Drude model with a corrected effective volume, resulting in a corrected electron density. The reported results have potential for developing nanosensors based on small nanoparticles below 5 nm in size by using their intrinsic response to adsorbed analytes. This detection scheme suggests a potential increase in the sensitivity of up to 3×, particularly when redox processes play a role, such as for the detection of reactive oxygen species.
Original languageEnglish
JournalThe Journal of Physical Chemistry Part C
Volume118
Issue number48
Pages (from-to)28075–28083
Number of pages9
ISSN1932-7447
DOIs
Publication statusPublished - 2014

Fingerprint Dive into the research topics of 'Size-Dependent Shifts of Plasmon Resonance in Silver Nanoparticle Films Using Controlled Dissolution: Monitoring the Onset of Surface Screening Effects'. Together they form a unique fingerprint.

Cite this