Molecule-plasmon coupling, plasmonic

The presence of interfaces within a polymer LED can also introduce additional nonradiative decay channels. This is particularly important in proximity to a metal electrode. Excitons which are able to diffuse to the metal surface are liable to be quenched directly by interaction with the metal wave function. This mechanism is therefore active only within a few nanometers of the interface. At larger distances (up to about 100 nm), excited molecules can couple to the surface plasmon excitations in the metal, thus providing a further nonradiative decay channel. The combined effects of changes in the radiative and nonradiative rates in two-layer LED structures have been modelled by Becker et al.,83 who have been able to model the variation in EL efficiency with layer thickness due to changes in the efficiency of exciton decay. 

Among the three models mentioned in Sec. 5.1 for molecular plasmonics, that using the point dipole model for the molecule is the most apt to introduce molecule-electrod3mamics coupling concepts [110, 111]. In this model, the molecule is punctiform, and only its dipolar properties are considered. In particular, the molecule is considered to have the same properties as in the vacuum (i.e. same transition moments, same polarizability). 

In the classification of models for metal-molecule electrodynamic coupling that we have done in Sec. 5.1, the model that we have described so far (a classical punctiform dipole close to a metal nanoparticle described as a continuous medium) is the simplest. While it has proven to be extremely useful, not only as a mean to grasp the basic physics of molecular plasmonics phenomena, but also to provide semi-quantitative and, sometimes, even quantitative results, it still remains a model empirical in nature. In this section we shall briefly describe models that goes beyond such an approach. 

The affinity (interaction strength), multiple interactions, and the changes in concentration can be also monitored from those studies. To deliver data in real time, the natural phenomenon of surface plasmon resonance (SPR) is employed. Since the refractive index (r ) at the interface changes as molecules are immobilized on the sensor surface, instant measure of r provides real-time assessment. The Tlcxchip platform exploits grating-coupled SPR (GC-SPR) for this purpose. 

Decreasing the BWF component of the G-mode in nanotube water solution and in a film with organic molecules supports the assumption that coupling between plasmon modes and the G-mode is weaker in individual nanotubes and thin bundles than in thick bundles. 

Here, 1 examine the coupling of particle plasmons excited in nanoparticles with LSPs in surface relief nanostructures. As a biosensor, nanoparticles may serve as linker molecules that amplify the index change due to ligand bindings with... 

The combination of plasmonics calculations to model the enhancing particles, and rigorous molecular treatment allow for a comprehensive model. The quantum optic model of Kali and co-workers [JO, 44] gives a unified treatment of a model molecule with two electronic states, and an arbitrary number of vibrational levels. Although more complete methods are possible, by adding different vibrational bands, for example, this includes the most important elements, and allows coupling to calculated plasmonic results. 

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