Thermal/electron irradiation assisted coalescence of Sc3N@C80 fullerene in carbon nanotube and evidence of charge transfer between pristine/coalesced fullerenes and nanotubes

Abstract

Sc₃N@C₈₀ fullerenes are inserted inside carbon nanotubes (CNTs). The results show that the thermal stability of Sc₃N@C₈₀ fullerenes is around 1200 °C for the fullerenes resting on the wall of CNTs. Internal fullerenes show stability up to 1300 °C, which portrays them as one of most stable types of fullerenes. Electron irradiation of the peapods at 90 kV leads to the formation of capsules inside the CNTs at 5 × 10⁹ e nm⁻² electron dosage. This value is an order of magnitude higher than the threshold of electron-induced damage in C₆₀ molecules. Electron energy loss spectroscopy confirms the presence of Sc atoms in capsules. Encapsulation of fullerenes and capsule formation changes the oxidation state of Sc atoms from +2.5 towards +3. This is an evidence of charge transfer between the fullerene/capsule cage and CNT walls.