Core-shell nanoparticle of silver coated with light-emitting rubrene: Surface plasmon enhanced photoluminescence

Silver (Ag) nanoparticles (NPs) with a diameter of 50-100 nm were fabricated by using a reduction process of silver nitrate with sodium citrate. Using the Ag NPs, hybrid core (Ag)-shell (organic light-emitting rubrene) NPs were prepared through a hydrothermal process. The formation of hybrid core-shell NP of Ag-rubrene was confirmed through transmission electron microscope images. From ultraviolet and visible absorption spectra, the Ag and rubrene characteristic peaks were simultaneously observed for the core-shell NPs. Using a high-resolution laser confocal microscope (LCM), the photoluminescence (PL) intensity of the Ag-rubrene core-shell single NP was about 300 times higher than that of the rubrene single NP. This remarkable enhancement of PL efficiency in the core-shell single NP is due to the energy transfer effect in the surface plasmon resonance coupling between Ag and rubrene materials. (C) 2011 Elsevier B.V. All rights reserved.