Intermolecular Interactions in Organic Dye Monolayers Formed by Langmuir-Blodgett Technique

Langmuir and Langmuir-Blodgett films of some organic dyes (perylene-like dyes, derivatives of 4-aminonaphthalimide, derivatives of naphthoylenebenzimidazole, azo dyes) and their mixtures with thermotropic liquid crystal or arachidic acid have been investigated. Surface pressure as a function of the mean molecular area for the Langmuir films were measured and information about organization of molecules at the air-water interface has been obtained. Absorption spectra in situ for the Langmuir films and both absorption and fluorescence spectra for Langmuir-Blodgett films were recorded. The results obtained from spectroscopic studies have led to conclusions about formation of self-aggregates of dye molecules, both in ground and excited states, at the phases interfaces. (author)