Individualized low-dimensional carbon allotropes: Enabling ground state and excited state charge transfer by molecular heptamethine cyanine

Abstract

Individualized single walled carbon nanotubes (SWCNTs) and exfoliated nanographene (NG) have been probed in the context of supramolecular interactions with an anionic heptamethine cyanine NIR-dye. The outstanding light-harvesting capability of the heptamethine cyanine permits to easily monitor the formation of the supramolecular hybrids by UV-Vis-NIR. Raman spectroscopy studies evidenced upshifted 2D bands and downshifted G bands for the obtained hybrids, which indicate the electronic n-doping of the carbon nanostructures caused by the heptamethine cyanine assembly. Furthermore, the electron donating character of the heptamethine cyanine in combination with SWCNTs and NG was corroborated in terms of a shift of charge density in the dark and in a transfer of charges upon photoexcitation.