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/d⁴ 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.