droplets wrapped in thin polymer shells allow for normal scattering. [14] However, PDLCs require a lot of power to sustain high transparency. Polymer-stabilized LCs (PSLCs) require little power when in either the normal transparent or scattering state and, thus, have recently been preferred. [15] PDLCs and PSLCs scatter sunlight as do curtains, but exclude less solar energy. Compared to nematic LCs, cholesteric LCs (CLCs) afford circularly selective reflection because of the spatially periodic variation of the dielectric tensor in the helical structure. CLCs allow smart windows to reflect solar energy regardless of environmental status, thus saving energy. [16][17][18][19] Vanadium dioxide (VO 2 ) exhibits a typical metal-insulator transition (MIT) triggered by electricity, thermal radiation, THz-frequency waves, and strain, associated with significant changes in resistivity and the optical and magnetic properties. [20,21] Thermotropic VO 2 that modulates NIR light penetration has been used to fabricate smart windows and manage the indoor thermal environment. [22][23][24][25][26][27][28][29] However, the MIT of VO 2 occurs at 68 °C, thus far in excess of a comfortable temperature, greatly hampering VO 2 utilization. Here, we develop a dualstimulus-responsive, normally transparent, WVO-PSCLCs flexible smart window using thermally stable polymer stabilized CLCs (PSCLCs) and a flexible, thermotropic, tungsten-doped VO 2 hybrid thin layer. Transparency is electrically switchable, and the window significantly modulates NIR light penetration under ambient conditions, thus weakly reflecting NIR light at room temperature and extensively scattering penetrated NIR light at 55 °C. The window is very resistant to pressing and bending, facilitating real-world use.

This paper introduces anisotropic nickel yttrium oxide (NYO) film formed by the brush coating technique. X-ray photoelectron spectroscopy confirmed well-formed NYO film after the curing process, and the morphology of the surface was investigated using atomic force microscopy. The shear stress driven from brush hair movements caused the nano/micro-grooved anisotropic surface structure of NYO. This anisotropic surface induced uniform liquid crystal (LC) alignment on the surface, which was confirmed by pre-tilt angle analysis and polarized optical microscopy. The contact angle measurements revealed an increase in hydrophilicity at higher temperature curing, which contributed to homogenous LC alignment. The NYO film achieved good optical transmittance and thermal stability as an LC alignment layer. In addition, the film demonstrated good electro-optical properties, stable switching, and significantly enhanced operating voltage performance in a twisted-nematic LC system. Therefore, we expect that this brush coating method can be applied to various inorganic materials to achieve an advanced LC alignment layer.

Liquid crystals (LCs) are an active area of interest for electro-optical devices, and the alignment of LCs has emerged as an extremely essential issue for LC devices. Evidence suggests that the surface topology of alignment layers plays a key role in both tuning the tilt angles and modulating the switching of LCs. Herein, nanotips are constructed by self-assembly of two different two-dimensional (2D) nanoflakes in PI hybrid alignment layers to modulate the switching of LCs. Both MoS2 nanotips and Ti3C2T x MXene nanotips were observed on hybrid thin layers, but MoS2 nanotips are much thinner and taller. The hybrid thin layers are highly transparent, and the nanotips penetrating the hybrid layers roughened the surface but moderately declined the surface energy. LCs are strongly anchored on hybrid alignment layers, and the nanotips were found to topologically hinder the in-plane switching of LCs and hence accelerate the rewriting speed of optical data. Besides the accelerated optical rewriting speed, the surface plasmon–polariton (SPP) of nanoflakes also substantially boosted the external electric field to switch LCs and hence remarkably diminished the operating voltage and likewise sufficiently shortened the response time. In particular, the optical rewriting time of LCs that homogeneously aligned on hybrid alignment layers with 0.5% MoS2 nanoflakes doping has been deduced to as short as 43.36 s, which is a decrease of 37.81% compared to that of PI alignment layers cell; LCs can be electrically driven to switch optical data at 2.51 V and return to their original alignment state within 24.142 ms. These results signify the promising applications of hybrid thin layers for both traditional LC devices and optical rewritable LC devices.