Broadband cholesteric liquid crystal devices with poly(N-vinyl carbazole) microstructures

Abstract

The particular thermally induced phase separation (TIPS) method was developed by using poly(N-vinyl carbazole) (PVK) dissolved in liquid crystal (LC) layer recently. Permanent scattering is produced via the particular TIPS due to the formation of poly-domain LCs. In this work, we applied the particular TIPS to a conventional cholesteric LC (CLC) device. A broadband CLC device with a poly-domain structure was demonstrated by using the particular TIPS of CLC and PVK. The CLC device fabricated by two indium tin oxide glass substrates coated with PVK films generated the rough PVK layers and microstructures when the device was cooled from a temperature higher than the clear point of CLCs. The produced poly-domain planar texture of CLCs still preserved the bistability. A high cooling rate and PVK concentration both increased the reflection bandwidth of the CLC devices.

Keywords:

• broadband
• cholesteric liquid crystal
• poly-domain structure
• thermally induced phase separation

Acknowledgements

The authors would like to thank the anonymous reviewers for their helpful comments.

Additional information

Funding

This work was supported by the Ministry of Science and Technology of Taiwan under Grant [NSC 100-2112-M-009-014-MY3] and [MOST 103-2112-M-009-013-MY3].