Issue 28, 2023

Topological defects stabilized by a soft twist-bend dimer and quantum dots lead to a wide thermal range and ultra-fast electro-optic response in a liquid crystalline amorphous blue phase

Abstract

Amorphous Blue phase, or BPIII, a mesophase exhibited by highly chiral liquid crystals, is increasingly being investigated for next-generation displays due to its attractive electro-optical properties, such as sub-millisecond response time, high contrast ratio and wide viewing angle. However, obtaining a fast-responding, thermally stable BPIII with commercial usability is still a challenge due to the frustrated nature of the phase. The study presented here investigates the thermal and electro-optic properties of the BPIII exhibited by a low molecular weight liquid crystalline system. Adding a twist-bend nematic dimer to a mixture comprising a nematic liquid crystal and chiral dopant helps stabilize the BPI, the cubic blue phase, due to the ultra-low bend elastic constant and saddle-splay deformation inherent to the dimer. Doping small concentrations of surface-functionalized quantum dots reduces the free energy associated with the topological defects leading to a complete transformation of the cubic blue phase to an amorphous one, with the latter exhibiting a wide thermal range. Polarizing optical microscopy, and electro-optical studies confirm the existence of BPIII over 34 °C spanning ambient and below/above ambient temperatures. The response time associated with the switching between achromatic dark and bright states is ∼200 μs, a value faster than that reported for low molecular weight systems and on par with polymeric ones. Furthermore, the BPIII exhibits a hysteresis-free optical transmittance with low operating voltages and high contrast ratio. A prototype device fabricated using the BPIII composite is found to be thermally, temporally and electrically stable, making it highly promising for display device applications.

Graphical abstract: Topological defects stabilized by a soft twist-bend dimer and quantum dots lead to a wide thermal range and ultra-fast electro-optic response in a liquid crystalline amorphous blue phase

Supplementary files

Article information

Article type
Paper
Submitted
09 3月 2023
Accepted
14 6月 2023
First published
15 6月 2023

J. Mater. Chem. C, 2023,11, 9686-9694

Topological defects stabilized by a soft twist-bend dimer and quantum dots lead to a wide thermal range and ultra-fast electro-optic response in a liquid crystalline amorphous blue phase

N. Khatun, V. Sridurai, K. F. Csorba and G. G. Nair, J. Mater. Chem. C, 2023, 11, 9686 DOI: 10.1039/D3TC00861D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements