Spontaneous helix formation in non-chiral bent-core liquid crystals with fast linear electro-optic effect.

Sithara P Sreenilayam,Carsten Tschierske,Vitaly P Panov,Marko Prehm,Anne Lehmann,Jagdish K Vij,Marco Poppe,Yuri P Panarin

doi:10.1038/ncomms11369

Sithara P Sreenilayam, Carsten Tschierske + Show 6 more

Open Access

https://doi.org/10.1038/ncomms11369

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Abstract

Liquid crystals (LCs) represent one of the foundations of modern communication and photonic technologies. Present display technologies are based mainly on nematic LCs, which suffer from limited response time for use in active colour sequential displays and limited image grey scale. Herein we report the first observation of a spontaneously formed helix in a polar tilted smectic LC phase (SmC phase) of achiral bent-core (BC) molecules with the axis of helix lying parallel to the layer normal and a pitch much shorter than the optical wavelength. This new phase shows fast (∼30 μs) grey-scale switching due to the deformation of the helix by the electric field. Even more importantly, defect-free alignment is easily achieved for the first time for a BC mesogen, thus providing potential use in large-scale devices with fast linear and thresholdless electro-optical response.

Highlights

Liquid crystals (LCs) represent one of the foundations of modern communication and photonic technologies
LCs used in industry, so far, are predominately nematics that consist of simple rod-like molecules[1]
A new class of compounds with ferroelectric and antiferroelectric LCs is built from achiral bent-core (BC) molecules and has engendered great scientific interest in recent years[4] due to a range of fascinating phenomena arising from the interplay of polarity and chirality[5,6,7]

Summary

Introduction

Liquid crystals (LCs) represent one of the foundations of modern communication and photonic technologies. We report the first observation of a spontaneously formed helix in a polar tilted smectic LC phase (SmC phase) of achiral bent-core (BC) molecules with the axis of helix lying parallel to the layer normal and a pitch much shorter than the optical wavelength. This new phase shows fast (B30 ms) grey-scale switching due to the deformation of the helix by the electric field. In contrast to other BC smectics, defect-free alignment is achieved, providing potential use in devices with fast linear and thresholdless electrooptical response

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Results

Conclusion