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Ю. П. Муха, А. М. Еременко, Н. П. Смирнова, А. О. Дорошенко*, И. П. Теренецкая**, Т. H. Орлова**
«Влияние наночастиц золота в матрице SiO2 на спек-тральные свойства и фотохимию адсорбированных молекул родамина 6Ж и провитамина D.»
813–828 (2010)

PACS numbers: 78.55.Mb, 78.67.Rb, 78.67.Ve, 82.50.Hp, 82.70.Uv, 87.14.Pq, 87.64.K-

Influence of low concentrations of gold nanoparticles (AuNPs) in the Au–SiO2 composite (0.02 wt.% Au) on the absorption and luminescence spectra of the adsorbed dye Rhodamine 6G (R6G) as well as on the photochemical behaviour of biologically active molecule of provitamin D3 is investigated. In colloidal AuNPs solutions, spectral behaviour of R6G molecules is determined by its interaction with stabilizer localized within the shell of the particle. The R6G spectra in the ground and excited states are not very sensitive to the gold particle protected by the layer of stabilizer. When heterogeneous R6G/Au/SiO2 system is in vacuum, the R6G photoluminescence is effectively quenched by gold nanoparticles. When air is added, adsorbed water molecules form a layer between the nanoparticles and dye, and resonance energy transfer from R6G to AuNPs accompanied with fluorescence enhancing occurs. The R6G kinetics decay obeys the biexponential equation and strongly depends on the ratio of the components. Au–SiO2 suspension in the solution of 7-dehydrocholesterol (7-DHC—provitamin D3) in ethanol has no significant effect on its phototransformations compared to previously studied kinetics of the photoreaction of 7-DHC in the presence of SiO2. The addition of Au–SiO2 particles into a nematic liquid crystal (NLC) doped with 7-DHC also does not have a noticeable effect on the kinetics of the photoreaction. The presence of Au–SiO2 at high concentrations in a cholesteric liquid crystal (CLC) mixed with 7-DHC results in a shift of selective reflection band of CLC, apparently due to the disordering of its structure. When heterogeneous composites based on metal nanoparticles in the SiO2 matrix with adsorbed organic compounds and biomolecules are fabricated, it is necessary to consider the possibility of formation of several adsorption states of molecules on the surface of silica.

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