Sunlight-driven smart windows with polymer/liquid crystal composites for autonomous control of optical properties

Abstract

We developed optically switchable smart windows driven by sunlight with polymer/liquid crystal (LC) composites containing azobenzene derivatives, which undergo trans–cis isomerization with high efficiency under sunlight. The composites exhibited high...

Novel sunlight-driven Cu7S4/VO2 composite films for smart windows

“…These films can automatically become opaque to block sunlight on scorching days and return to a transparent state under low lighting conditions. In addition, T. Ube et al 35 developed optically switchable smart windows powered by sunlight using polymer/liquid crystal composites. These films all have excellent properties.…”

Photoinduced solid-to-liquid transition of an N-benzylideneaniline derivative towards smart glass

“…The initial state of the smart glass here was translucent, and became transparent after UV irradiation, which is different from the energy saving smart windows relying on photochromism, electrochromism, 36 thermochromism, and liquid crystals. 37,38 The reported smart windows based on azobenzene, viologen derivatives, silver halide, spiropyran and terephthalate derivatives are transparent in the initial state and become opaque after stimuli. 36 The smart glass in this study restored the translucent state spontaneously and quickly after removal of UV light, without the assistance of another wavelength light.…”

Sunlight-Driven Smart Windows with a Wide Temperature Range of Optical Switching Based on Chiral Nematic Liquid Crystals

“…37 a push−pull azobenzene sensitive to visible light. 38 In these systems, trans−cis photoisomerization of azobenzene moieties is induced by sunlight, which leads to a smectic−chiral nematic phase transition. The initial transparent state with a smectic phase in homeotropic alignment, in which LC molecules align normal to the substrates, changes to a scattering state along with phase transition to a chiral nematic phase.…”

“…However, drivable temperature ranges are narrow in these photoinduced phase transition systems: in our previous study, for instance, temperature should be in the range of 35−48 °C even for the device containing a high concentration (10 mol %) of azobenzene derivatives to allow switching by sunlight. 38 For practical use as smart windows, devices should work in wider temperature ranges.…”