A new design strategy for efficient electro-optic single-component organiccrystals

A new, theoretically-derived synthetic concept for designing geometrically optimized, single-component organic crystals for the electro-optic effect, is presented. The idea relies on the mechanism responsible for the spontane ous evolution of polarity in channel-type inclusion compounds consisting of non-polar hosts. Single, elongated, rod-like molecular structures which in corporate both a strongly hyperpolarizable core and peripheral, non-polaria ble R-groups, may mimic the two-component structures of the polar inclusion compounds. In both systems, the energy difference in the lateral direction s between antiparallel and parallel alignment of the active molecules is as sumed to be approximately zero, and terminal functional group interactions along the direction of alignment are responsible for polarity evolution. By choosing molecules in which the direction of the largest hyperpolarizabili ty is common with the geometric long axis, then efficient crystals for the linear electro-optic effect are envisaged. (C) 1999 Elsevier Science Ltd.