V. Percec, M. Glodde, T. K. Bera, Y. Miura, I. Shiyanovskaya, K. D. Singer, V. S. K. Balagurusamy, P. A. Heiney, I. Schnell, A. Rapp, H.-W. Spiess, S. D. Hudson, and H. Duan, Nature 419, 384-387 (2002).
Self-organized organic nanostructures with controlled optoelectronic properties that facilitate ultrahigh density nanopatterning represent one of the challenges of molecular electronics. Charge carrier mobility (µ) in organic materials is mediated by pi-stacking of conjugated groups, a principle resembling that of base pairs in DNA. Examples are disc- and rod-like molecules stacked in discotic hexagonal and calamitic liquid crystals (LCs), and acenes in single crystals. The ensuing development of these architectures requires the synthesis of novel complex molecules and the elaboration of new processing techniques for LCs, and single crystals. Here, we report a universal strategy to functional fluorinated tapered dendrons programmed to self-assemble into supramolecular nanocylinders containing pi-stacks of high electron (µe) or hole (µh) mobility donors (D), acceptors (A) or D-A complexes in the core. The co-assembly of D- or A-dendrons with amorphous polymers containing A or D side groups, respectively, incorporates the polymer backbone in the center of the cylinder via pi-stacks of D-A interactions and enhances µ of the parent polymer. These supramolecular cylinders self-process into homeotropically aligned hexagonal and rectangular columnar LCs that pattern ultrahigh density arrays (up to 4.5 x 1012 cylinders per square centimeter) between electrodes. Below glass transition temperature, a complex and organized optoelectronic matter of cylinders composed of helical dendrons jacketing stacks of aromatic groups with even higher µ, insensitive to ionic impurities, is produced. Such arrays are uniquely applicable to devices spanning from single supramolecule to nanoscopic and to macroscopic scales including transistors, photovoltaics, photoconductors, photorefractives, light emissives, and optoelectronics.
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