Abstract

Hemicyanine dyes containing long alkyl chains have attracted considerable attention in recent years due to their significance as possible optoelectronic and molecular electronic materials. With large non-linear molecular polarizabilities, amphiphilic hemicyanines are readily incorporated into Langmuir-Bludgett monolayer and multilayer films, forming artificial molecular assemblies with preferred spatial and orientational order [1,2], In contrast to centrosymmetric bulk materials, in which the individual effects are canceled, and the overall bulk second-order susceptibility vanishes [1], highly aligned structures ensure non-zero macroscopic second-order susceptibilities, χ⁽²⁾. In addition molecular assemblies of these materials have been shown to be characterized by extended electronic states in which the relationship between molecular structure and delocalization of the electronic states is a matter of current interest.

© 1994 Optical Society of America