Self-assembled quasi one-dimensional nanostructures of pi-conjugated molecules may find use in future optoelectronic devices due to their intriguing properties, which include sharp exciton transitions, strong circular dichroism, high exciton mobilities, and photoconductivity. However, many applications require depositing these nanostructures from their liquid environment to a solid substrate, which is a challenge to achieve without destroying their delicate supramolecular structure.

In a recent publication (D.M. Eisele et al., Nature Nanotechnology 4 (2009) 658) Dörthe M. Eisele and Stefan Kirstein from the group of Jürgen P. Rabe at Humboldt University Berlin in collaboration with David A. Vanden Bout at the University of Texas at Austin and Jasper Knoester at the University of Groningen report on the use a drop-flow technique to immobilize double-walled tubular J aggregates of amphiphilic cyanine dyes without affecting their morphological or optical properties. High-resolution images of the topography and exciton fluorescence of individual J-aggregates are obtained simultaneously with polarization-resolved near-field scanning optical microscopy (NSOM). These images exhibit a remarkably uniform supramolecular structure, both along individual nanotubes and between nanotubes in an ensemble, demonstrating their potential for light harvesting and energy transport (s.a. Focus "Organic semiconductors" and Editorial "Organics settle down").

The work was carried out within the SFB 448 "Mesoscopically Organized Composites".