Hollow gold nanostructures prepared by Galvanic replacement reaction: synthesis and optical properties

Abstract

The synthesis of hollow Au nanostructures is described, using the galvanic replacement reaction with Ag nanoparticles as the templates. The effect of reaction conditions, including PVP concentration and reaction time on the morphology of the Ag templates was investigated. Using Ag nanocubic-shape templates, 50 nm hollow Au nanostructures were prepared. The results indicated that the plasmon resonance of the hollow Au nanostructures was strongly affected by the amount of Au precursor and could be tuned between 460 and 860 nm by simply altering the volume of the Au precursor solution from 0.5 mL to 3 mL. The hollow Au nanostructures were heated with an 808 nm laser (1.8 W), which showed that the sample temperature reached 55 oC after just 5 min irradiation. The ease of synthesis the hollow Au nanostmctures with a plasmon peak in the near infrared of relatively small size and high capacity of conversion of photon energy into heat makes them a novel and promising material for photo-thermal and -imaging applications.