Molecular orientation and photorefractive effects in single-wall carbon nanotubes doped nitrile-ester mixture liquid crystals

We report the electro-optical properties of liquid crystal cells containing pure nitrile-ester mixture liquid crystal (NEMLC) and its doped form with 0.05% (wt/wt) single-wall carbon nanotubes (SWCNT). Diffraction efficiencies of 441-nm pump and 632-nm probe beams were measured in two-wave mixing experiment. Efficiencies and rise time were found to increase in SWCNT doped nematic liquid crystals. A maximum diffraction efficiency of ∼15% was found for cell doped with SWCNT, while cells without SWCNT had a maximum efficiency of 7%. We also have observed that photoconductivity in SWCNT doped liquid crystals is highly dependent on the light intensity. This is attributed to the doping, which enhances the efficient photo-charge generation, combined with enlarged conductivity.