Self-Assembly of Au Nanoparticles and Quantum Dots by Functional Sol-Gel Silica Layers

A layer-by-layer (LbL) self-assembled method has been developed to create the nano architectonics consisted of quantum dots (QDs) including hydrophobic CdSe/CdZnS and hydrophilic CdTe and Au nanoparticles (NPs) through a functional silica layer as a linker on a slide glass. The glass layer was created by the hydrolysis of 3-aminopropyltrimethoxysilane (APS), in which the amino group in APS plays an important role for the connection among QDs and Au NPs. UV-vis and PL spectroscopy, scanning electron microscopy, and transmission electron microscopy were employed to characterize. The result reveals that Au NPs or QDs could be dispersed in the glass slides at a high concentration, and little aggregation. The PL intensity and absorbance is linearly increased with the number of dipping cycles. Furthermore, when the glass layer between Au NPs and CdTe QDs is thin, the PL of the QDs quenched because of the Plasmon-enhanced fluorescence resonance energy transfer. In contrast, the bright PL of the QDs was observed when the glass layer became thick. The LbL self-assembled glass film shows excellent stability and transparency, which can make a promise for application in biochemical, optoelectronic, and clinical diagnosis areas.