Synthesis of Au Nanorod@Amine-Modified Silica@Rare-Earth Fluoride Nanodisk Core-Shell-Shell Heteronanostructures

We report here the synthesis of water-dispersible Au nanorod (NR)@ amine-modified silica@rare-earth fluoride (REF3) nanodisk (ND) heteronanostructures (HNs). The HN fabricated as such represents a rational approach to the concurrent improvements in luminescence, water dispersibility, and other application-specific properties (such as those useful for photothermal therapy). A Au NR is deployed as an internal plasmonic antenna to couple the emission of rare-earth (RE) ions to the surface plasmon resonance (SPR) of the Au NR for enhanced photoluminescence. An intervening amine-modified silica shell is used to attach the ultrathin REF3, to spatially separate them from the internal Au NR antenna, and to impart good water dispersibility all at the same time. Use of internal Au NR plasmonic antenna rather than the more common approach of external antenna may also be applied to design of other REF3 HNs to improve the application performance.