Polar Orientation of Dyes in Robust Multilayers by Zirconium Phosphate-Phosphonate Interlayers

Abstract

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.

Thickness dependence of second-harmonic generation in thin films fabricated from ionically self-assembled monolayers

“…These include electric-field poled polymers, [1][2][3] Langmuir-Blodgett films, [4][5][6] and covalent selfassembled monolayer structures. [7][8][9] We report here detailed studies of a ionically self-assembled monolayer technique for the creation of noncentrosymmetric organic thin films with substantial (2) values. The advantages of this technique include simple, rapid, inexpensive production, and long-term stability of the induced (2) without the need for additional processing such as electric-field poling or chemical reactions.…”

Zirconium phosphonate/1,4,5,8-naphthalenediimides self-assembled films

“…The substrates were previously treated by known procedure (Katz et al 1991). The treatment resulted in a surface rich in phosphonate groups, which adsorbed a layer of Zr +4 when exposed to an aqueous solution of ZrOCl 2 .…”

Nonlinear Optical Zeolite Films for Second and Third Harmonic Generation

“…The conventional methods to prepare 2O-NLO materials based on the organic 2O-NLO dyes can be classified into (1) the crystallization of the 2O-NLO dyes, (2) the preparation of 2O-NLO dyepolymer physical mixtures or preparation of 2O-NLO dyetethering polymers on optically transparent supports followed by electrical poling, 1,2,9-13 (3) the formation of selfassembled mono-or multilayers of 2O-NLO dyes on optically transparent supports, [4][5][6][7][8] and (4) the incorporation of 2O-NLO dyes into large (~130 μm) zeolite powders or the powders of the related nanoporous materials.…”