Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5397623 | Journal of Luminescence | 2017 | 8 Pages |
Abstract
The interactions of dye molecules with gold nanoparticles are of great interest owing to the potential applications in the areas of bioimaging, sensing and photodynamic therapy applications. In many cases the distances between fluorophores and the metal particles can change during the experiment and the spectral features of the units are not taken into account. In this work, the fluorescence behaviour of two dyes with different spectral properties (Rhodamine B and 9-aminoacridine) are investigated in the presence of gold nanoparticles having diameters of 2 or 26Â nm and hence different plasmonic properties. In order to fix the distance between the dye and the gold nanoparticles, the dyes are entrapped in 20Â nm silica nanoparticles, and the metal colloids are adsorbed on the silica surface. The distance between the fluorescent units and the metal particles is tuned by growing additional silica layers on the pristine nanoparticles. Steady-state and time-resolved fluorescence measurements show that in the presence of gold nanoparticles, having 2Â nm diameter, a drastic quenching of the dye emission is observed, for all the prepared samples, despite the average dye-metal distances. When gold nanoparticles with 26Â nm diameters are used, their interactions with the dyes are strongly dependent on the averaged distances between the metal colloids and the dyes and on the overlap of their spectral properties. Indeed, an enhanced emission is observed for 9-aminoacridine while the fluorescence of longer wavelength emitting Rhodamine B is quenched. The steady state and time-resolved data are analysed to evaluate the plasmonic impact of the radiative and non-radiative rate constants of the dyes.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Luigi Tarpani, Loredana Latterini,