Investigations on organic fluorophore doped silica nanoparticles by apertureless scanning near-field optical microscopy

Colloidal nanoparticles represent an interesting class of materials as they exhibit unique optical, electronic and magnetic properties. Nanoscale optical imaging is essential for observing in detail the optical properties of these materials and for optimizing the associated synthesis procedures in order to make them fit a specific purpose. In the presented experiment we have employed Apertureless Scanning Near-Field Optical Microscopy (ASNOM) for imaging silica nanoparticles that incorporate through covalent bonds an organic fluorophore, 9-aminoacridine. Our results consolidate the current lines of evidence which show that ASNOM imaging has the potential to image both morphological and optical properties of colloidal nanoparticles in very high detail.