Temperature and concentration dependence of J-aggregate of a cyanine dye in a Laponite film fabricated by Langmuir–Blodgett technique

In this communication, we report the temperature and concentration dependence of J-aggregate of a cyanine dye N, N′-dioctadecylthiacyanine perchlorate (NK) in the Laponite film fabricated by Langmuir–Blodgett technique. Surface pressure area per molecule isotherm revealed the formation of stable Langmuir monolayer at the air–water interface. Spectroscopic characterization confirmed the formation of J-aggregates in the NK LB film without Laponite. In the hybrid film, J-aggregate forms at lower Laponite concentration (1 ppm), higher deposited surface pressure and at lower subphase temperature. Both the J-aggregated films were found to be optical second harmonic generation (SHG) active and mechanically very stable, although intrinsically NK is SHG inactive.