Spectroscopic study of fluorescent naphthoylenebenzimidazole derivatives in Langmuir–Blodgett films: Self-aggregates formation

Some derivatives of naphthoylenebenzimidazole as well as their mixtures with arachidic acid have been incorporated in Langmuir and Langmuir–Blodgett films. Surface pressure versus mean molecular area isotherms for Langmuir films were recorded and the organization of molecules at the air–water interface has been estimated. Absorption spectra in situ for Langmuir films and both absorption and fluorescence spectra for LB films have been recorded. The results obtained from spectroscopic studies have led to conclusions about formation of self-aggregates by dye molecules at interfaces. In the ground electronic state some fraction of the I- and J-type aggregates have been created, whereas in the excited state the creation of genuine excimers has been observed.