Applications columnar discotics

Hence, columnar (discotic) liquid crystals with an aromatic central core are of significant interest for application in OLEDs as an HTL, if the columnar phase can be aligned with the columns orthogonal to the substrate surface, i.e. the flow of holes from the anode to the ETL and/or emission layer is... 

Therefore, miscibility in discotic columnar mesophase is recognized as a result of molecularly dispersed systems. However, we should pay some attention to a state of mixture for two discogens to form the identical columnar mesophase. As a more realistic system, is it a molecularly dispersed or a single-component column dispersed system This is an essentially important question when we consider the application of discotic liquid crystalline blends as a new tool for organic electronic materials (Fig. 8.4). 

Balazs, et al. (86) further show that for more concentrated ranges of disks, the various plastic solid (edge to face) and columnar (discotic) phases appear. As described above, the isotropic phase corresponds to an exfoliated composite. Fortunately, most of the interesting areas of application require only modest concentrations of montmorillonite clay. 

Chapter IX Applicable Properties of Columnar Discotic Liquid Crystals.781... 

We start by reminding ourselves that columnar discotic liquid crystals are comprised of disordered stacks (1-dimensional fluids) of disc-shaped molecules arranged on a two-dimensional lattice (Fig. 1) [1]. This structure imparts novel properties to these materials from which applications are likely to stem. One such property is the transport of charge along the individual molecular stacks [2-7]. The separation between the aromatic cores in, for example, the hexa-alkoxytriphenylenes (HATn), the archetypal columnar discotic mesogen, is of the order of 0.35 nm, so that considerable overlap of n orbitals of adjacent aromatic rings is... 

PAH chemistry is of practical as well as theoretical interest. PAHs can be regarded as well defined subunits of graphite, an important industrial material, which is so far not totally understood at the macroscopic level. In this context, it is our aim to delineate the molecular size at which the electronic properties of PAHs converge to those of graphite. Furthermore, alkyl substituted derivatives of hexabenzocoronene (HBC) form discotic mesophases and, therefore, provide opportunities for materials which allow one-dimensional transport processes along their columnar axis [83,84]. Their application for photovoltaics and Xerox processes is also of current interest. 

Understanding the organization of disc-shaped mesogens in columnar phases is of practical interest because of their useful optoelectronic applications [168-170]. It will be instructive to explore the role of fluctuations in influencing transport properties of thermotropic discotic liquid crystals—in particular, in the columnar phase. 

Directing Self-Organized Columnar Nanostructures of Discotic Liquid Crystals for Device Applications... 

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