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

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-Fe2O3) 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.

Graphical abstractThe optical properties of colloidal hematite spindles can be easily tailored through the growth of Au continuous shells or the deposition of Au nanorods.Figure optionsDownload full-size imageDownload as PowerPoint slide