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. (c) 2014 Elsevier B.V. All rights reserved.