Synthesis and characterization of gold cubic nanoshells using water-solubleGeO2 templates

Abstract

Size-tunable GeO2 nanocubes were initially prepared by a modified sono-assisted reverse micelle method and thenfunctionalized with an amino-terminated silanizing agent. Subsequently, gold decoratedGeO2 nanocomposites wereprepared at pH ≈ 7 and 80 °C. It was found that well-dispersed gold nanoparticles onGeO2 nanocubes could be obtained only if gold salt is abundant to favor simultaneous,homogeneous nucleation of gold particles. Additional gold ions were reduced onto theseattached ‘seed’ particles accompanied by synchronous dissolution of water-solubleGeO2 cores, resulting in gold hollow cubic shells. TheGeO2 nanocubesand Au/GeO2 nanocomposites as well as gold hollow cubic shells were characterized by transmissionelectron microscopy, scanning electron microscopy, x-ray diffraction and UV–visiblespectroscopy. In particular, gold hollow cubic shells feature a plasmon resonance peakat above 900 nm, which renders it quite promising in biochemical applications.