Fullerene-functionalized carbon nanotubes as improved optical limiting devices

We report the synthesis, characterization and optical limiting behavior of a nanohybrid built by grafting C-60-fullerenes on carbon nanotubes (CNTs). The nonlinear optical limiting properties of the CNT-C-60 complex were investigated at wavelengths where C-60 does not absorb. We found that the nanohybrid had superior performances to those of CNTs and fullerenes, either taken individually or as a mixture. This enhanced optical limitation of the nanohybrid suggests not only cooperative but also synergistic effects between the two carbon forms. A mechanism involving higher excitonic states of the CNTs formed by Auger recombination of low energy excitons is proposed. (C) 2011 Elsevier Ltd. All rights reserved.