ZnO nanorod incorporated nematic liquid crystal for high multiplexing and high refresh rate displays

Zinc oxide nanorods incorporated in nematic liquid crystal matrix (NLC) are observed to improve physical properties of NLC and its device parameters, especially, for displays. In this article, we present the results of effect of incorporation of zinc oxide nanorods of various sizes but similar aspect ratio on physical properties of NLC. Zinc oxide nanorods (ZR) of similar aspect ratio (4-5) but different sizes (diameter: length) abbreviated as., ZR1 (10:50 nm), ZR2 (50:200 nm) and ZR3 (1:5 mu m) are synthesized. Nanocomposites of synthesized nanorods with wide temperature range NLC are prepared. Smaller nanorods (ZR1) are expected to form chain like structures in host NLC matrix leading to softening of order parameter at the isotropic-nematic (I-N) transition. As the size of the nanorods increases the discontinuity of order parameter at I-N transition is observed to increase. Enhancement of dielectric anisotropy as well as birefringence which in turn indicates increase in the order parameter of the system is observed with the incorporation of zinc oxide nanorods. Reduction of threshold voltage, electro-optic response time and bulk ac conductivity and enhanced bend to splay elastic constant ratio of the nanocomposite samples as compared to pure NLC is observed with the incorporation of ZR in host NLC. Observed results show that nanorods of size similar to 50: 200 nm are the most suitable to be incorporated in NLC for high multiplexing display devices.