Fullerene-driven encapsulation of a luminescent Eu(iii) complex in carbon nanotubes

Abstract

A novel CNT-based hybrid luminescent material was obtained via encapsulation of a C₆₀-based Eu(III) complex into single-, double- and multi-walled carbon nanotubes (SWCNTs, DWCNTs and MWCNTs, respectively). Specifically, a luminescent negatively charged Eu(III) complex, electrostatically bonded to an imidazolium-functionalized fullerene cage, was transported inside CNTs by exploiting the affinity of fullerenes for the inner surface of these carbonaceous containers. The filling was performed under supercritical CO₂ (scCO₂) conditions to facilitate the entrapment of the ion-paired assembly. Accurate elemental, spectroscopic and morphological characterization not only demonstrated the efficiency of the filling strategy, but also the occurrence of nano-ordering of the encapsulated supramolecular luminophores when SWCNTs were employed.