Energy Transfer between Confined Dye and Surface Attached Au Nanoparticles of Mesoporous Silica

Abstract

Nanoscale architectures have been designed by entrapping rhodamine 6G dye molecules into the channels of mesoporous silica and Au nanoparticles anchor onto the surface of the mesoporous matrix. The surface energy transfer between confined dye and Au nanoparticles has been studied by steady state and time-resolved spectroscopy. The appearance of second surface plasmon band at 680 nm with increasing the concentration of mesoporous silica indicates the formation of self-assembled structure of Au nanoparticles which is established by TEM and DLS studies. A mechanism for self-assembled Au nanoparticles is proposed. The PL quenching (76.3% to 27.4%) and energy transfer efficiency (51.8% to 17.4%) can be tuned with changing the arrangement of Au nanoparticles. Analysis reveals that the energy transfer from dye to Au nanoparticles is a surface energy transfer process and it follows 1/d 4 distance dependence. This anisotropy decay reveals that the dye molecules are aligned inside the channels of mesoporous silica. Such energy transfer between confined dye and Au nanoparticles could pave the way for designing new optical based materials for the application in chemical sensing or light harvesting system.

Nanoscale Strategies for Light Harvesting

“…The supramolecular organization of the dyes inside the porous materials leads to a large change in the initial anisotropy, which suggests the unidirectional energy transfer. Using the concept of encapsulation of dye inside the porous materials for light harvesting, a system was designed that encapsulates Rhodamine 6G dye molecules inside the mesoporous silica channels, and Au nanoparticles are attached on the surface of the mesoporous silica to investigate the energy transfer between dye and Au nanoparticle (Figure A) . It is evident that the rotational motion of the dye is restricted due to encapsulation of the dye inside the channels of the porous materials and that will eventually modify the photophysical properties of the dye molecules .…”

“…(A) Rhodamine 6G (R6G) dye encapsulated by mesoporous silica with Au nanoparticles attached to the mesoporous matrix used to study energy transfer, and the lower panel shows fluorescence anisotropy decay curves of R6G dye in the presence of Au NPs. Reprinted with permission from ref . Copyright 2010 American Chemical Society.…”

Numerical studies of the interaction of an atomic sample with the electromagnetic field in two dimensions

“…Their studies have lead to many applications such as coherent EM energy transport in space [16], surfaceenhanced Raman spectroscopy (SERS) [17] and tip-enhanced microscopy [18]. Recent attention has focused on optical control scenarios, ranging from coupled exciton-plasmon dynamics in semiconductor nanodots [19][20][21][22][23][24][25][26][27] and in molecular aggregates [28][29][30][31][32][33][34][35][36], where metal NPs affect excitation energy transfer between molecules, to optical trapping of single atoms or molecules [37][38][39][40]. Such applications are facilitated by the possibility to control the geometry of nanomaterials (NP size, their relative arrangement, etc.)…”

Modulated fluorescence properties in fluorophore-containing gold nanorods@mSiO2

“…We reason that surface photonic energy transfer occurs between DOX and the GNR or MSN matrix. 29 Therefore, the uorescence enhancement could be attributed to a rational combination of GNR@mSiO 2 with embedded DOX.…”