Fast dual-mode switchable smart window based on the dual-frequency liquid crystal electrohydrodynamic instability

Abstract

In the past decade, liquid crystals for use in switchable smart windows have become a research hotspot. Dual-frequency liquid crystals (DFLCs), in particular, are now widely studied and applied in fast-response liquid crystal devices. In this work, we determine that a DFLC scatters light when a voltage frequency close to its crossover frequency is applied. The principle behind this phenomenon is then investigated. The experimental results show that the scattering of light is a dynamic process that is caused by ion perturbation. Based on the results of this investigation, a double-layer liquid crystal (LC) shutter is prepared. It is shown that the fabricated device can be quickly switched between transparent, dark, and scattering states solely by changing the voltage frequency; this ability also has a useful application in connection to privacy-protecting smart windows. The DFLC is combined with dynamic scattering to accelerate the response time of the scattering.