Self-Assembly of Functional Organic Chromophores

Abstract

Aggregate structures of organic chromophores strongly affect their properties and so has become an active area of research. Self-assembly and supramolecular methods present important means to influence aggregation processes, and these have become active areas of research. We have studied the self-assembly of differently structured chromophore molecules with emphasis on porphyrins,1 pyrazinacenes,2 hexabenzocoronenes (HBC) and oligophenylenes (such as sexiphenyl), and the various methods of doing this including molecular design, surface assembly (under ambient or UHV conditions), and using interfacial media such as in the Langmuir and Langmuir-Blodgett techniques. For the latter, we have applied principles of amphiphilicity to generate on-interface structures,3 which can be lifted as multilayered films and exploited for the preparation of electronic devices.4 In this work, we will describe the self-assembly properties based on precipitation/gelation, assembly at solid surfaces, and interactions at an air-water interface. We will emphasize the molecular structure as a key feature including the effects of π-π stacking, conformational flexibility and amphiphilicity. Self-assembly and supramolecular techniques stand out as the most effective methods for obtaining nanomaterials having the molecule-level definition of structure important for any applications of the resulting materials.