Engineering nanoscaled nonliner optical thin film via Langmuir-Blodgett technique

In this study, a novel amphiphilic nonlinear optical (NLO) molecule which can form a monolayer at the air-water interface was demonstrated. Also, in-plane coherence and long-range order in multilayered thin films are achieved by manipulating the experimental parameters such as temperature, surface pressure, rate of compression, and transfer ratio. A fundamental understanding of how molecules come together to form a monolayer was gained and the process of transferring the monolayer from the air-water interface to the solid (glass) substrates was optimized. It therefore allows control over thin film properties governed by structural order at the molecular level. NLO measurement is used as a complementary tool in determining the structure related thin film properties. The quadratic increase of a second harmonic signal with increasing film thickness implies the sign of sustaining noncentrosymmetric order throughout the film.