Issue 9, 2023

High birefringence liquid crystals with a wide temperature range and low melting point for augmented reality displays

Abstract

A series of tolane liquid crystals terminated by but-3-enyl with high performance (such as high clearing point, low melting point, high birefringence Δn, low viscosity γ1, and broad nematic phase interval) were designed and synthesized in accordance with the phase-only liquid-crystal-on-silicon (LCoS) device requirements for AR displays. The effects of the lateral fluoro-substituent, central alkyne bond, terminal group, and flexible n-alkyl chain on the thermal properties were systematically investigated, and density functional theory (DFT) calculations of molecular conformation and aspect ratio were used to corroborate the experimental results. Further, their properties of phase transition temperature, birefringence, and viscosity were comprehensively evaluated in two typical LC mixtures (001, P02-F). The results indicate that our target compounds can effectively lower the melting point, broaden the working temperature interval, and maintain a high Δn and low γ1 for three LC mixtures. One new LC mixture by employing compound 2TFV as a LC dopant exhibited a high Δn (∼0.26), moderate γ1 and dielectric anisotropy (∼6.3), and broad temperature adaptability (−31.3 °C to 91.3 °C), and achieved 2.08π phase modulation, 5 V operation voltage, and 2.89 ms response time at 40 °C in a reflective LCoS device.

Graphical abstract: High birefringence liquid crystals with a wide temperature range and low melting point for augmented reality displays

Supplementary files

Article information

Article type
Paper
Submitted
25 Jan 2023
Accepted
30 Mar 2023
First published
31 Mar 2023
This article is Open Access
Creative Commons BY-NC license

Mater. Adv., 2023,4, 2119-2126

High birefringence liquid crystals with a wide temperature range and low melting point for augmented reality displays

R. Chen, L. Zhao, Y. Li, J. Li, P. Chen, X. Chen and Z. An, Mater. Adv., 2023, 4, 2119 DOI: 10.1039/D3MA00042G

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