Enhancement and quenching of photoluminescence from Au nanoparticles and CdTe quantum dot composite system

Abstract

New composite systems consisting of Au nanoparticles (NPs) and CdTe quantum dots (QDs) are fabricated by spin coating chemically synthesizing CdTe QDs on silica substrates which have already been implanted by Ag ions through using a metal vapor vacuum arc (MEVVA) ion source implanter. By thermally annealing the Au ions implanted silica substrates, the growth and redistribution of Au NPs can be controlled, the influence of localized surface plasmon (LSP) of Au NPs on the photoluminescence (PL) of CdTe QDs is well studied. The optical properties, surface morphologies, microstructures, and light emission properties of the Au-ion implanted samples are investigated by using optical absorption spectroscopy, atomic force microscopy, transmission electron microscopy and PL spectra measurements. PL spectra show that the PL intensities from Au NPs and CdTe QDs composite systems can be enhanced or quenched compared with those of CdTe QDs directly spin coated on bare silica substrate. The underlying interaction processes between Au NPs and CdTe QDs are discussed in depth, and the new mechanisms for the PL enhancement and quenching in the Au-CdTe coupled systems are put forward. These results provide a good reference for the future designing of optoelectronic devices with improved luminescence efficiency by LSP of metal NPs.