Electro-optical devices from organically doped sol-gel materials

Transparent porous matrices made by the sol-gel method are ideal as hosts for active photoactive or electroactive organic dopants. Sol-gel optics applications are related to an adequate and precise control of the compositional and pore surface variations in the cage of trapped molecules, which is necessary to the preparation of novel optical and electrooptical gel-glasses. Gel-glass dispersed liquid crystal (GDLC) with electrooptical properties shall be presented as an application of the sol-gel process for trapping microdroplets of nematogenic organic compounds (i.e., liquid crystals, LCs). GDLC films may be used as electrooptical devices. Upon application of an external electric field, unaltered GDLCs were made to switch from white opaque to colorless transparent states. The different electrooptic features of GDLCs, including GDLC performances for color display applications are reviewed.