Polar orientation of dyes in robust multilayers by zirconium phosphate-phosphonate interlayers.

Polar orientation of molecules in solids leads to materials with potentially useful properties such as nonlinear optical and electrooptical activity, electrochromism, and pyroelectricity. A simple self-assembly procedure for preparing such materials is introduced that yields multiple polar dye monolayers on solid surfaces joined by zirconium phosphate-phosphonate interlayers. Second harmonic generation (SHG) shows that the multilayers have polar order that does not decrease with increasing numbers (up to a large number) of monolayers in the film. The inorganic interlayers, as determined by SHG, impart excellent orientational stability to the dye molecules, with the onset of orientational randomization above 150 degrees C.