Absorption and Scattering of Light by Hybrid Metal/J-Aggregate Nanoparticles: Plasmon-Exciton Coupling and Size Effects

作者：Lebedev Vladimir S^*; Medvedev Anton S

来源：Journal of Russian Laser Research, 2013, 34(4): 303-322.

DOI：10.1007/s10946-013-9356-5

• nanophotonics
• absorption and scattering of light
• plasmon-exciton interaction
• size-dependent effects
• hybrid nanoparticles
• metal/J-aggregate complexes
• cyanine dye

We report the results of our theoretical studies of the optical properties of hybrid nanoparticles consisting of the metal core covered with molecular J-aggregates. We evaluate the cross sections of absorption and scattering of light by such particles on the basis of the extended Mie theory for two concentric spheres with material dielectric functions that take into account the size effect associated with scattering of free electrons from the core/shell interface. We carry out our calculations in a wide range of light wavelengths and geometrical parameters of the composite system for silver and gold core and for a J-aggregate shell composed of different cyanine dyes. The results obtained demonstrate the quite different behavior of the extinction spectra of such particles caused by the different strengths of interaction between the Frenkel exciton and the dipolar or multipolar plasmons. We pay particular attention to the investigation of spectral peak positions associated with the eigenfrequencies of hybrid modes in the system and peak intensities as functions of reduced oscillator strength in the molecular J-band for various relationships between the core radius and shell thickness. This provides an efficient means for the explanation of the main features in the optical properties of metal/J-aggregate nanoparticles and can be used for an effective control of the plasmon-exciton coupling strength in such hybrid complexes.

• 出版日期2013-7