Self-assembly of organic semiconductor nanostructures via organic solid-solid wetting deposition. Organic Semiconductor Group Dr. Frank Trixler
Organic Semiconductor
          Group Dr. Trixler
Nanoscale Guided Self-assembly

 
Locally guided growth of two vertically orientated semicondcutor nano-chains. The orientation of the Quinacridone chains is related to the scanning direction. © F. Trixler.


We achieve locally guided growth of organic semiconductor nanostructures by utilising direction-dependent stabilities of supramolecular chains. For example, linear chains are self-assembled from Quinacridone molecules via Hydrogen bonds (H-bonds). Force-Field Calculations of supramolecular binding energies for different directions revealed that such chains are most resistant against tip-sample interactions if the stress, resulting from these interactions, is induced parallel to the H-bond direction.

As a consequence, our approach is based on the adjustment of the degree and direction of the induced stress. By setting the tip-sample distance to a degree which only allows the growth of wire nuclei aligned with their H-bond direction nearly parallel to the stress direction (nanomanipulation direction or fast scan direction respectively), orientation selective growth can be achieved as non-parallel aligned wire nuclei are less resistant against the stress and thus are being desorbed and replaced.

Our approach enables to steer the self-assembly of nanostructure without relying on external templates. This allows repeated changes of structural complexity of self-assembled monolayers down to the regime of ~10 nm.


Publications:

Various approaches to control solid/solid wetting self-assembly of organic semiconductors with STM.
F. Trixler, W.M. Heckl, In: Mendez-Vilas, A.; Diaz, J. (Eds.):
Modern Research and Educational Topics in Microscopy (2), 534-541. Formatex, Badajoz (2007).
ISBN: 978-84-611-9420-9.
 
Supramolecular self-assembly initiated by solid-solid wetting.
F. Trixler, T. Markert, M. Lackinger, F. Jamitzky, W.M. Heckl.
Chem. Eur. J. 13 (27), 7785-7790 (2007).
DOI: 10.1002/chem.200700529.



PUBLIC ENGAGEMENT