All (2002-Present)  SS21  WS21  SS22  WS22  SS23  WS23  SS24

 Karl Franzens University Graz

Graz University of Technology 

Liquid Crystalline Semiconductors
Yves Geerts
Universite Libre de Bruxelles
17:15 - 18:15 Tuesday 01 March 2011 TUG P2

Discotic (disc-like) molecules typically comprising a rigid aromatic core and flexible peripheral chains have been attracting growing interest because of the fundamental importance as model systems for the study of charge and energy transport and due to the perspectives of their application in organic electronic devices. The talk will cover various aspects of the recent research on discotic liquid crystals, in particular, molecular concepts, supramolecular structure, processing of ordered thin films and fabrication of electronic devices. The size and chemical structure of the conjugated core of discotic molecules govern, to a large extent, their electronic properties. Variation of the peripheral flexible chains and connecting groups between side chains and aromatic core is decisive for the tuning of self-assembly in solution and in bulk. Special attention is given to the interesting synthetic concepts based on low-symmetry disc-like molecules have received. Supramolecular organization of discotic molecules is closely related to the molecular design and can be efficiently controlled by the suitable processing methods. In particular, approaches to obtain suitable macroscopic orientations of columnar superstructures on surfaces, that is, planar uniaxial or homeotropic alignment, will be discussed together with appropriate processing techniques. Finally, an overview of charge transport in discotic materials and their application in semiconducting devices will be given. More information and publications are available at : http://www.ulb.ac.be/sciences/chimpoly.

Selected recent publications :
1. M. Cavallini et al. Adv. Mater. 2009, 21, 4688–4691
2. G. Schweicher et al. Chem. Mater. 2009, 21, 5867–5874
3. B. Tylleman et al. Chem. Mater., 2009, 21 (13), 2789–2797
4. M. P. de Jong et al. J. Phys. Chem. C 2008, 112, 15784-15790
5. A. Calo et al. J. Am. Chem. Soc. 2008, 130, 11953-11958
6. M. Palma et al. Soft Matter 2008, 4, 303-310
7. P.-O. Mouthuy et al. Nano Lett. 2007, 7, 2627-2632
8. S. Sergeyev et al. Chem. Soc. Rev. 2007, 1902-1929
9. S. Sergeyev et al. J. Mater. Chem. 2007, 1777-1784