Hole transport is through dye in a PVK-matrix photorefractive polymer

Summary form only given.Most of the efficient photorefractive polymers that have been reported to date are based on a composite of an electro-optic dye and an electronegative sensitizer doped into a charge transport polymer, usually poly(N-vinylcarbazole), (PVK). One early variation of this was to use a passive host such as polymethylmethacrylate together with a charge transport dopant, in place of the charge transport polymer, which illustrates that hole transport by hopping between donor molecules present at 30 wt%. or more may be efficient. There is evidence from IR spectroscopy that the electro-optic dye has an additional role as a compensator, storing positive charge. There have also been reports that the high dipole moment of the electro-optic dye leads to a reduction in the mobility of hole transport through the PVK matrix. We report on time of flight measurements on a known photorefractive polymer composite incorporating PVK and an analogous composite in which the host matrix is polycarbonate, which is a dielectric. Surprisingly, the composite with the polycarbonate host yields an improved hole mobility relative to the PVK-based composite.