Aggregates formation by perylene-like dyes in Langmuir–Blodgett films

Langmuir–Blodgett (LB) films formed of some organic dyes, namely 3,4,9,10-tetra-(n-alkoxy-carbonyl)-perylenes, and their mixtures with arachidic acid have been studied. The electronic absorption and fluorescence spectra were recorded. The results obtained have led to conclusions about formation of self-aggregates of dye molecules at the air–solid substrate interface. The absorption spectra have indicated that in the ground state some fraction of J-aggregates can be formed, whereas the fluorescence spectra have been dominated by the emission from excimer states.