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.

Enhanced Bandwidth Broadening of Infrared Reflector Based on Polymer Stabilized Cholesteric Liquid Crystals with Poly(N-vinylcarbazole) Used as Alignment Layer

“…PVK is an organic semiconductive polymer for hole transport, which has been widely applied as an electro-optic material for its photoconductive characteristics [ 34 , 35 ]. In the meanwhile, PVK has been applied previously for fabricating broadband CLC devices through particular thermally induced phase separation (TIPS) [ 36 ]. The method involves a combination of the dissolution process of PVK dissolved in the LC layer, and it has been successfully applied for fabricating scattering mode LC light shutters with low driving voltage and fast response [ 37 ].…”