| 초록 |
PVK shows a quite good feature in photorefractive system, but photoconductive polymers are limited by low charge mobilities and short exiton diffusion lengths. On the other hand nanocrystalline TiO2 has the excellent charge-transport ability enough to be used in photovoltaic cell as an electron-transport electrode, but it has no charge-trapping sites so that it is not enough to be used in photorefractive system as a photoconductive layer. If individual advantages of two materials can be taken selectively, the photorefractive effect of layer-structured system would be enhanced remarkably. To obtain similar kind of enhancement, we fabricated mesoporous TiO2/C60-doped PVK nanocomposite by infiltrating C60-doped PVK into mesoporous TiO2. Using this nanocomposite film as a photoconductive layer, we fabricated layer-structured photorefractive liquid crystal cells, having superior diffraction efficiencies. This enhancement of diffraction efficiency is due to the photogenerated charge recombination blocking effect of mesoporous TiO2 layer. |
