In this paper, we investigate the emission characteristics of a molecule placed in the gap of a nanoparticle dimer configuration. The emission process is described in terms of a local field enhancement factor and the overall quantum yield of the system. The molecule is represented as a dipolar source, with fixed length and fed by a constant current. We first describe the coupled dimer-molecule system and compare these results to a single sphere-molecule system. Next, the effect of dimer size is investigated by changing the radius of the nanoparticles. We find that when the radius increases, a saturation effect occurs that trends towards the case of a radiating dipole between two flat interfaces, which we refer to as a parallel plate waveguide geometry. An analytical solution for the parallel plate waveguide geometry is presented and compared to the results for the spherical dimer configuration. We use this approximation as a reference solution, and also, it provides useful guidelines to understand the physical mechanism behind the energy transfer between the molecule and the dimer. We find that the emission intensity undergoes a quenching effect only when the inter-nanoparticle gap distance of the dimer is very small, meaning that strong coupling prevails over energy engaged in the heating process unless the molecule is extremely close to the metal surface.

Distance dependent quenching effect in nanoparticle dimers / POLEMI, Alessia; Kevin L., Shuford. - In: THE JOURNAL OF CHEMICAL PHYSICS. - ISSN 0021-9606. - ELETTRONICO. - 136(2012), pp. 184703-184707. [10.1063/1.4711759]

Distance dependent quenching effect in nanoparticle dimers

POLEMI, Alessia;
2012

Abstract

In this paper, we investigate the emission characteristics of a molecule placed in the gap of a nanoparticle dimer configuration. The emission process is described in terms of a local field enhancement factor and the overall quantum yield of the system. The molecule is represented as a dipolar source, with fixed length and fed by a constant current. We first describe the coupled dimer-molecule system and compare these results to a single sphere-molecule system. Next, the effect of dimer size is investigated by changing the radius of the nanoparticles. We find that when the radius increases, a saturation effect occurs that trends towards the case of a radiating dipole between two flat interfaces, which we refer to as a parallel plate waveguide geometry. An analytical solution for the parallel plate waveguide geometry is presented and compared to the results for the spherical dimer configuration. We use this approximation as a reference solution, and also, it provides useful guidelines to understand the physical mechanism behind the energy transfer between the molecule and the dimer. We find that the emission intensity undergoes a quenching effect only when the inter-nanoparticle gap distance of the dimer is very small, meaning that strong coupling prevails over energy engaged in the heating process unless the molecule is extremely close to the metal surface.
136
184703
184707
Distance dependent quenching effect in nanoparticle dimers / POLEMI, Alessia; Kevin L., Shuford. - In: THE JOURNAL OF CHEMICAL PHYSICS. - ISSN 0021-9606. - ELETTRONICO. - 136(2012), pp. 184703-184707. [10.1063/1.4711759]
POLEMI, Alessia; Kevin L., Shuford
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11380/1011733
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