Wet adsorption of a luminescent Eu^III complex on carbon nanotubes sidewalls

A Eu^III complex, tris-dibenzoylmethane mono-1,10-phenanthroline- europium(III) [Eu(DBM)₃(Phen)], can be easily adsorbed in situ via hydrophobic interactions to single-walled carbon nanotube (SWNT) surfaces from a methanol solution. The Eu^III containing material has been comprehensively characterized via thermogravimetric analysis (TGA), UV-vis-NIR absorption and luminescence spectroscopy, Raman spectroscopy, atomic force microscopy (AFM), high-resolution transmission electron microscopy (HR-TEM)), Z-contrast scanning transmission electron microscopy (STEM) imaging, and energy dispersive X-ray spectroscopy (EDS). The photophysical investigations revealed that the presence of a SWNT framework does not affect the lanthanide-centered luminescence stemming from the characteristic electronic transitions within the 4f shell of the Eu^III ions. Such straightforward synthetic route leads to the preparation of luminescent SWNTs without significantly affecting the electronic and structural properties of the carbon framework, opening new possibilities of designing new classes of CNTs for biomedical applications.