Optical properties of noble-metal nanoparticles coated with a dye J-aggregate monolayer
- P N Lebedev Physical Institute, Russian Academy of Sciences, Moscow (Russian Federation)
- Moscow Institute of Physics and Technology (State University), Dolgoprudnyi, Moscow Region, Russian Frderation (Russian Federation)
We report experimental and theoretical studies of the optical properties of composite nanoparticles consisting of a noble-metal (Ag or Au) core and a cyanine dye J-aggregate shell. Using transmission electron microscopy, the particles have been shown to be spherical in shape and 4 - 10 nm in size. The crystal structure of their core has been determined by 1-keV electron diffraction. The absorption spectra of such nanoparticles in aqueous suspension show two peaks, one dueto the plasmon resonance in the metallic core, and the other to electronic excitations in the J-aggregate shell. These results are interpreted in a model based on the expression for the absorption cross section of small particles, using polarisability calculations for two concentric spheres with allowance for the size effect on the dielectric function of the metallic core. The dielectric function of the J-aggregates is derived from experimental data using Kramers - Kronig relations. The shape and position of the peaks in the absorption spectra of the hybrid nanoparticles are strongly dependent ontheir geometry and the optical properties of the core and shell materials. This offers the possibility of controlling the optical properties of composite materials based on such nanoparticles. (nanostructures)
- OSTI ID:
- 21471399
- Journal Information:
- Quantum Electronics (Woodbury, N.Y.), Journal Name: Quantum Electronics (Woodbury, N.Y.) Journal Issue: 3 Vol. 40; ISSN 1063-7818
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
ABSORPTION SPECTRA
COHERENT SCATTERING
COMPOSITE MATERIALS
CONFIGURATION
CORRELATIONS
CROSS SECTIONS
CRYSTAL STRUCTURE
CYANINE DYES
DATA
DIELECTRIC MATERIALS
DIFFRACTION
DYES
ELECTRICAL PROPERTIES
ELECTRON DIFFRACTION
ELECTRON MICROSCOPY
ELEMENTS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXPERIMENTAL DATA
GOLD
INFORMATION
KEV RANGE
KRAMERS-KRONIG CORRELATION
MATERIALS
METALS
MICROSCOPY
NANOSTRUCTURES
NUMERICAL DATA
OPTICAL PROPERTIES
PARTICLES
PEAKS
PHYSICAL PROPERTIES
POLARIZABILITY
RESONANCE
SCATTERING
SILVER
SPECTRA
SPHERES
SPHERICAL CONFIGURATION
TRANSITION ELEMENTS
TRANSMISSION ELECTRON MICROSCOPY