Hematite spindles with optical functionalities: Growth of gold nanoshells and assembly of gold nanorods

Abstract

The layer-by-layer (LBL) assembly method, combined with the seeded growth technique, have been used to deposit gold shells on the surface of hematite ( α-Fe 2O 3) spindles. While the LBL method yields dense coatings of preformed Au nanoparticles, when AuCl − 4 ions are further reduced by a mild reducing agent, thicker, rough nanostructured shells can be grown. The deposition process was monitored by TEM and UV–visible spectroscopy, demonstrating a gradual change in the optical features of the colloids as the surface is more densely covered. The particles so-prepared can find useful applications in cancer therapy and as SERS substrates. Additionally, we show that Au nanorods can be assembled on hematite spindles, providing a flexible way to tune the optical properties of the resulting composite colloids.