Akademska digitalna zbirka SLovenije - logo
E-resources
Full text
  • Electrically Tunable Reflec...
    Feng, Chenrun; Saha, Rony; Korblova, Eva; Walba, David; Sprunt, Samuel N.; Jákli, Antal

    Advanced optical materials, 11/2021, Volume: 9, Issue: 22
    Journal Article

    The recently discovered ferroelectric nematic (NF) liquid crystals (LCs) with over 0.04 C m−2 ferroelectric polarization and 104 relative dielectric constants, coupled with sub‐millisecond switching, offer potential applications in high‐power super capacitors and low voltage driven fast electro‐optical devices. This paper presents electrical, optical, and electro‐optical studies of a ferroelectric nematic LC material doped with commercially available chiral dopants. While the NF phase of the undoped LC is only monotropic, the chiral NF phase is enantiotropic, indicating a chirality induced stabilization of the polar nematic order. Compared to undoped NF material, a remarkable improvement of the electro‐optical switching time is demonstrated in the chiral doped materials. The color of the chiral mixtures that exhibit a selective reflection of visible light in the chiral NF phase, can be reversibly tuned by 0.02–0.1 V µm−1 in‐plane electric fields, which are much smaller than typically required in full‐color cholesteric LC displays and do not require complicated driving scheme. The fast switchable reflection color at low fields has potential applications for LC displays without backlight, smart windows, shutters, and e‐papers. The newly discovered ferroelectric nematic (NF) phase becomes enantiotropic when doped with two commercially available chiral dopants. The selective reflection of visible light of the NF∗ phase can be reversibly tuned in sub‐milliseconds by only 0.02–0.1 V µm−1 in‐plane electric fields, which are much smaller than full‐color displays need, and do not need complicated sequential driving scheme.