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.