Nanostructures Seminar Series at MIT

Co-sponsored by The Nanostructures Lab, The Tiny Tech Club and Techlink.


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	About the Series
	Sponsors:
	Nanostructures Lab
	Tiny Tech
	Techlink

Optoelectronic and Biophotonic Applications of Metal Nanoparticles

Professor Thomas A. Klar

Photonics and Optoelectronics Group, Sektion Physik and CeNS,

Ludwig-Maximilians-Universität München

Background Papers for Talk:

Biomolecular Recognition Based on Single Gold Nanoparticle Light Scattering
Nano Letters, Vol. 3, No. 7, 935-938 (2003)

A method for biomolecular recognition is reported using light scattering of a single gold nanoparticle functionalized with biotin. Addition of
streptavidin and subsequent specific binding events alter the dielectric environment of the nanoparticle, resulting in a spectral shift of the
particle plasmon resonance. As we use single nanoparticles showing a homogeneous scattering spectrum, spectral shifts as small as 2 meV
can be detected.

Fluorescence Quenching of Dye Molecules near Gold Nanoparticles:
Radiative and Nonradiative Effects

Phys. Rev. Lett., Vol. 89, No. 20, 203002 (2002)

The radiative and nonradiative decay rates of lissamine dye molecules, chemically attached to differently sized gold nanoparticles, are investigated by means of time-resolved fluorescence experiments. A pronounced fluorescence quenching is observed already for the smallest nanoparticles of 1 nm radius. The quenching is caused not only by an increased nonradiative rate but, equally important, by a drastic decrease in the dye’s radiative rate. Assuming resonant energy transfer to be responsible for the nonradiative decay channel, we compare our experimental findings with theoretical results derived from the Gersten-Nitzan model.

References for More Information:

TBD

Noble metal nanoparticles show a pronounced optical resonance in the visible range of the electromagnetic spectrum, the so called nanoparticle plasmon resonance. This resonance is caused by a collective oscillation of the conduction band electrons and manifests itself in the scattering as well as in the absorption spectrum.

Metal nanoparticles interact strongly with their immediate nanoenvironment: Nanoparticles absorb energy from surface bound fluorescent molecules but also change their radiative lifetime. Hence, fluorophore/gold-nanoparticle composite systems are promising resonant energy transfer pairs. Furthermore, a change in the refractive index of the surrounding shifts the scattering spectrum of the nanoparticles. These effects open up ways to novel and fascinating applications in biophotonics and optoelectronics

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