Self-assembly of aminoclay template-assisted J-aggregate fibers

Abstract

The self-assembly of molecular building blocks is important in the construction of nanoscale architectures with unique properties. J-aggregate molecular building blocks are formed by the self-assembly of porphyrin antenna units that display good light-harvesting and self exciton trapping properties. Porphyrin-based J-aggregate suprastructures self-organized into rods, tapes, bundles, and tubes on the nanoscale level. J-aggregates must be stabilized under acidic conditions, and techniques for achieving the self-assembly of discrete J-aggregates under such conditions must be developed to increase the mechanical, thermal, and chemical stabilities of the aggregates. Herein, the supramolecular wrapping of J-aggregate fibers with water-solubilized aminoclay and oligomers is introduced. The addition of aminoclay to J-aggregate solutions induced formation of silica-sheathed J-aggregate hybrid suprastructures. In case of addition of low molecular weight oligomers strengthened the stability of the wrapped J-aggregate fiber bundles via the association between the cationic oligomer dispersions and the anionic SO- 4 groups of the J-aggregates, which preserved the optical properties of the J-aggregates at (or near) neutral pH. Interestingly, acidification of the porphyrin/oligomer mixtures produced J-aggregate hybrid suprastructures with a uniform diameter. The hybrid components described here are anticipated to be useful in optoelectronic devices and energy-related systems. © 2012 American Scientific Publishers. All rights reserved.