title: Electro-optical characteristics of ZrO2 nanoparticle doped liquid crystal on ion-beam irradiated polyimide layer.
abstract: It is well known that doping liquid crystals (LCs) with nanoparticles can readily change the physical and electro-optical properties of LC mixture. In this paper, we report on how the electro-optical properties and thermal stability of an LC system were enhanced by dispersing zirconia (ZrO2) nanoparticles in nematic LCs on ion-beam irradiated polyimide layers. Homogeneous LC alignment was achieved and ZrO2/LC mixture was applied in twisted-nematic (TN) mode. The addition of ZrO2 nanoparticles contributed to improvement of electro-optical properties in the TN LC cell by lowering voltage operation and decreasing response time. The TN LC cells with a ZrO2 nanoparticle concentration of 2.0 wt% showed the lowest threshold voltage of 2.0 V and the fastest response time of 15.3 ms. This enhanced electro-optical performance was likely due to van-der waals interactions and the screening effect of the ZrO2 nanoparticles in the LC medium. The thermal stability of the ZrO2/LC mixture was also improved compared to a pristine LC system.
authors.affiliation: Department of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-Ro, Seodaemun-Gu, Seoul 120-769, Republic of Korea.
authors.forename: Hong-Gyu
authors.initials: HG
authors.lastname: Park
authors.forename: Hyung-Jun
authors.initials: HJ
authors.lastname: Kim
authors.forename: Myoung-Seong
authors.initials: MS
authors.lastname: Kim
authors.forename: Il-Hwan
authors.initials: IH
authors.lastname: Lee
authors.forename: Dae-Shik
authors.initials: DS
authors.lastname: Seo