Chapter 15
Novel Photorefractive Materials Based on Multifunctional Organic Glasses 1
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Qing Wang, Nikko Quevada, Ali Gharavi, and Luping Yu
Department of Chemistry and The James Franck Institute, The University of Chicago, 5735 South Ellis Avenue, Chicago, IL 60637
A small molecular system based on carbazole moiety was developed for photorefractive applications. One of the molecules has been shown to form stable and amorphous films and exhibit good photorefractive performance. A net optical gain of 11 cm was observed. An attractive feature of this molecule is that its photorefractive response is fast. Because of its structural versatility, this molecular system is worth further exploration. -1
In this paper, we describe the synthesis and characterization of a multifunctional, small molecular system based upon carbazole moiety for photorefractive applications. It is known that photorefractive effect causes refractive index change in a noncentrosymmetric material due to photoinduced space-charge field and electro-optic effect. (7) Thus, to manifest photorefractive effect, a material must possess photoconductivity and electro-optic response. This is one of the design principles for the synthesis of the above mentioned molecules. Carbazole and its derivatives have long been recognized as good photoconductors and extensive work on composite photorefractive materials have revealed that carbazole containing systems exhibit an efficient photorefractive effect (2-5) Carbazole also has the flexibility for structure modification. By attaching a nonlinear optical (NLO) chromophore to the carbazole, this molecule will exhibit dual functions necessary for the photorefractive effect photoconductivity and second-order NLO activity. Furthermore, in our approach, the photocharge transport and the electro-optic (EO) functions are performed by two separate constituents. This provides us the flexibility of maximizing both charge transport and NLO activity separately and fine-tuning the photorefractive performance. A small amount (
