Polymer films of J-aggregated cyanine dyes and metal clusters for non-linear optical applications

Abstract

A new medium with non-linear optical properties, comprising J-aggregates of cyanine dyes entrapped in a polymer matrix is reported. Pseudoisocyanine and benzothiazolium dyes with C₂H₅ and C₁₈H₃₇ chains were synthesized; Langmuir–Blodgett and polymer films of these dyes were prepared. The temperature stability of the J-aggregates in films was investigated by optical spectroscopy. J-Aggregates in polymer films display a higher thermal stability than those in Langmuir–Blodgett films and can be used in non-linear susceptibility experiments. The cubic susceptibility of the films was measured by four-wave mixing and found to be 0.8 × 10^–7 cm³ erg^–1 for the degenerate case. Upon addition of metal clusters to the J-aggregate–polymer composite, an increase by a factor of >30 in the susceptibility was observed.