Abstract

The Langmuir-Blodgett (LB) technique allows high-quality organic films with the precision of a single molecular layer to be prepared. The preparation involves the transfer of individual monolayers from the top of a liquid subphase onto the surface of a solid substrate. Although the film thickness can be controlled precisely using such a technique, the orientation of the molecules and many other structural properties of the film depend heavily on, e.g., the materials used and the details of the process. There are methods to examine the structure of the prepared films, but their number is limited and some of them require rather complicated instrumentation (e.g. X-ray diffraction techniques). In this paper, we show that second-harmonic generation (SHG) can provide detailed and reliable information about the molecular ordering in the films of even very low symmetry.

© 2007 IEEE