Periodic electro-optical characteristics of ion-doped Smectic A phase liquid crystals driven by a low-frequency electric field

ABSTRACT

Functional liquid crystal (LC)-based electro-optical materials are promising candidates in a wide range of smart fields due to their excellent external stimuli-responsive characteristics. Herein, ion-doped Smectic A (SmA)-phase LCs gradually change from a transparent to a scattering state and then return to the transparent state via a circularly driven low-frequency electric field. All optical states can be maintained after removing the electric field. This phenomenon is due to charge transport and convection effects that appear and disappear periodically in SmA LCs doped with suitable ionic liquids. Diverse periodic characteristics were observed upon applying electric fields with different waveforms (e.g. square, sawtooth, and sine). Furthermore, the optical contrast of the periodic feature was abated by increasing the frequency of the electric field. These ion-doped SmA LCs can be widely used in multi-stable optical devices, optical switches, and timers, etc.

Graphical Abstract

KEYWORDS:

• Liquid crystals
• Smectic A phase
• periodic
• low-frequency electric field

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Key R&D Program of China (grant no. 2018YFB0703700), the National Natural Science Foundation of China (NSFC) (grant nos. 51333001, 51602007, and 51573003), and the joint fund of the Ministry of Education for Equipment Pre Research (grant no. 6141A020222).