Electrically Switchable and Permanently Stable Light Scattering Modes by Dynamic Fingerprint Chiral Textures

Ko Ting Cheng, Po Yi Lee, Malik M. Qasim, Cheng Kai Liu, Wen Fa Cheng, Timothy D. Wilkinson

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Negative dielectric nematic liquid crystals (LCs) doped with two azobenzene materials provide electrically switchable and permanently stable scattering mode light modulators based on dynamic fingerprint chiral textures (DFCT) with inhomogeneously helical axes. These light modulators can be switched between transparent (stable large domains of DFCT) states and scattering (stable small domains of DFCT) states by applying electric fields with different frequencies. The generation of DFCT results from the long flexible side chains of the doped chiral dopant. That is, if the DFCT can be obtained, then the large domains of DFCT reflect an intrinsically stable state. Moreover, the stabilization of the small domains of DFCT are caused by the terminal rigid restricted side chains of the other doped chiral dopant. Experimentally, the required amplitude to switch the light modulator from a scattering (transparent) state to a transparent (scattering) state decreases as the frequency of the applied electric field increases (decreases) within the set limits. This study is the first report on the advantages of the light scattering mode of DFCT, including low operating voltage, permanently stable transmission, wide viewing angle, high contrast, and polarization-independent scattering and transparency.

Original languageEnglish
Pages (from-to)10483-10493
Number of pages11
JournalACS Applied Materials and Interfaces
Volume8
Issue number16
DOIs
StatePublished - 27 Apr 2016

Keywords

  • bistability
  • cholesterics
  • dynamic scattering
  • fingerprint texture
  • light modulator
  • liquid crystal

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