Stable hazy states by electrohydrodynamic convection of ultraviolet-treated chiral nematic liquid crystal

In this paper, we show that electrohydrodynamic convection of ultraviolet (UV)-treated chiral nematic liquid crystals (CNLCs) generates stable foggy states. UV-irradiation produces relatively heavier and lar-ger molecular ions at CNLC mixture, which activates electroconvection, and leads to easily dynamic scat-tering mode (DSM) with strong turbulence. Chirality of LC combined with the DSM builds two stable states (planar state and focal conic state) more strongly, unlike the conventional method generating the two states in the CNLCs. The molecular ion effect enables state conversion to a much lower switching voltage than that of the conventional cholesteric devices. The focal conic state connected to DSM2 exhi-bits a stable deep hazy state, the mixed state combined with DSM1 displays a stable weak hazy state, and the planar state activated in a particular frequency region creates a stable and very clear transparent state due to the chiral pitch of the infrared region. Therefore, a smart window with the tri-stable-hazy state specialized in low power consumption can be realized. The tri-stable-hazy state device also generates various hazy states according to the applied voltage; thus, it can provide a proper indoor temperature for users. Furthermore, a stable planar state with a chiral pitch designed in the infrared region may save energy through selective reflection of infrared rays from the sunlight in the summer. The proposed tech-nology is suitable for commercial use in the next-generation smart window. (c) 2022 Elsevier B.V. All rights reserved.