Date of Award

6-2001

Document Type

Union College Only

Degree Name

Bachelor of Science

Department

Chemistry

Language

English

Abstract

The field of photonics relies on nonlinear optical (NLO) materials and their unique light interacting properties to guide and manipulate light for such uses as optical switches and optical data storage. Hybrid organic-inorganic composites offer excellent routes to such materials synthesis. We report herein the first study of neutral organic NLO chromophores adsorbed onto hectorite and laponite clay films. Seven different dyes (disperse red 1; disperse red 13; disperse red 19; disperse orange 3; disperse orange 13; disperse orange 25, and DANS, [4-dimethylamino-4' -nitrostilbene]), and two exchangeable cations (sodium and zinc), are used to create the hybrid films. The nature of the dye aggregation is characterized using UV/VIS spectroscopy, Xray diffraction, and second harmonic generation (SHG). Both J and H type aggregates are observed. The type and extent of aggregation is found to be primarily dependent on the functionalized structure of the dye molecule. The relative populations of aggregating versus bulk dye is found to depend on the amount of available clay surface area, which is affected by host clay particle size and the intergallery cation charge density. J aggregation is maximized at 0.10 w/w% dye in the zinc-laponite system. We found that the overall maximum dye loading levels are above 10 w/w% for the laponite system and between 1 and 5 w/w% for hectorite. Laponite is more ideally suited for optical device applications given its low background absorption. Currently the composite films do not show any second harmonic generation even though J aggregates have been shown to exhibit enhanced SHG in related systems.

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