Polymer-stabilized bistable dual-frequency cholesteric liquid crystal devices assisted by a predesigned chiral dopant

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 9; no. 46; pp. 16672 - 16681
• Main Authors: Liu, Chun-Yen, Yen, Chi-Feng, Hung, Yi-Hua, Tu, Chia-Min, Wu, Guan-Yi, Chen, Hung-Yi
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 02.12.2021
• Subjects: Cholesteric liquid crystals; Clean energy; Electronic devices; Energy consumption; Ferroelectric materials; Ferroelectricity; LCDs; Liquid crystal displays; Nematic crystals; Photonic crystals; Polymers; Response time; Step voltage
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/d1tc04354d

Liquid crystals have great potential for developing photonic devices that control the optical behaviors of liquid crystals in smart devices with external stimulation. In this study, we have demonstrated a series of bistable cholesteric liquid crystal devices using the dual-frequency nematic liquid crystal HEF951 assisted by a predesigned chiral ferroelectric liquid crystal. The synthesized chiral ferroelectric liquid crystal was used to induce the formation of the cholesteric liquid crystal phase and decrease the driving voltages and response times of the fabricated bistable liquid crystal devices. The fabricated ferroelectric liquid crystal-assisted bistable cholesteric liquid crystal devices showed a stable opaque focal conic state and stable transparent planar state without any energy consumption once they were turned "from focal-conic to planar" and "from planar to focal-conic". To enhance the reliability, the fabricated bistable cholesteric liquid crystal devices were further stabilized by polymer matrixes. Switching of the bistable liquid crystal cells from one state to another was achieved by a one-step voltage bias with various frequencies. Furthermore, the response time of the sample cell was calculated as 1.7 ms. These results suggest that fabricated ferroelectric liquid crystal-assisted bistable cholesteric liquid crystal devices can be applied to produce energy-saving green liquid crystal displays and other related smart devices. Fabricated polymer-stabilized bistable cholesteric liquid crystal devices show a stable opaque focal conic state and a stable transparent planar state without any energy consumption once they are turned.