Evaporative deposition of SiO<sub>2</sub> nanoparticles multilayer on ITO substrates and application for vertical alignment of liquid crystals - Effect of dichroic dye
Ankit Rai Dogra, Vandna Sharma, Partha Khanra, Pankaj Kumar
Abstract
Abstract In this work the SiO 2 nanoparticles layer was deposited by solvent evaporation on ITO substrates and used for vertical alignment of pure and dye doped liquid crystal (LC) in confined cells. The pure nematic liquid crystal (NLC) material was filled into SiO 2 layer coated cell by the capillary injection method. The 0.5 wt.% of dichroic dye added into the LC mixture and studied its effect on electro-optic behaviour of display cell. The FESEM study reveals the multilayered deposition of the SiO 2 on Indium tin oxide (ITO) substrates. Conoscopic and polarised optical microscopy (POM) study show good dark black and bright textures at OFF and ON state under the cross polarizers and confirm vertical alignment (VA) of LC molecules. The electro-optical (E-O) study shows the lower threshold and operating voltage with higher contrast ratio in dye doped vertically aligned LC (VALC) cell as compare to the pure SiO 2 coated VALC cell.