Multi-stable cholesteric liquid crystal windows with four optical states

ABSTRACT

An electrically switchable multi-stable liquid crystal device is demonstrated based on a non-uniform cholesteric liquid crystal (CLC) structure in a single cell. The non-uniform CLC structure consists of a polymer stabilised CLC layer and a non-polymer stabilised CLC layer. By taking advantage of the difference in driving electric field strength of the two layers, the device can be switched electrically to four different states: the reflecting state, the reflecting and scattering co-existing state, the scattering-only state and the transparent state. The optical properties of the four states and the transition conditions between the states were elucidated. Moreover, all states with reflecting and/or scattering properties are stable for an extended period of time after switching off the electric field. Thanks to its multi-stability, this device can be used for energy-saving smart windows of automobiles, buildings and in architectural aesthetics. An electrically switchable multi-stable liquid crystal device is demonstrated based on a non-uniform cholesteric liquid crystal (CLC) structure in a single cell. The device can be switched electrically to four different states. All states with reflecting and/or scattering properties are stable for an extended period of time after switching off the electric field. Thanks to its multi-stability, this device can be used for energy-saving smart windows of automobiles, buildings and in architectural aesthetics.

Graphical abstract

KEYWORDS:

• Multi-stable
• electricity driven
• non-uniform cholesteric
• switchable windows

Acknowledgments

Thanks Prof. Albertus P.H.J. Schenning from Eindhoven University of Technology for discussion.

Disclosure statement

No potential conflict of interest was reported by the author(s).

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Additional information

Funding

L. M. and H. S. contributed equally to this work. This study was supported by the Natural Science Foundation of China under Grant [No. 51503070, 51603069]; Science and Technology Program of Guangzhou [No. 2019050001]; Natural Science Foundation of Guangdong Province under Grant [No. 2020A1515010724, 2016A030310432, 2017A030313287]; Guangdong Provincial Key Laboratory of Optical Information Materials and Technology [No. 2017B030301007]; Guangdong Recruitment Program of Foreign Experts [No. 191900025]; MOE International Laboratory for Optical Information Technologies and the 111 Project; Natural Science Foundation of Jiangxi Province [No.20192BAB203011]; Yunnan expert workstation [202005AF150028].