Flexible smart window with controllable visible transmittance and high near-infrared shielding properties doped by CsxWO3/SiO2-SH nanoparticles

Abstract

Smart windows with controllable visible transmittance and high near-infrared (NIR) shielding properties have heightened demands for applications in buildings. Herein, we present a hybrid composite film that can control the visible transmittance and shield NIR light via incorporating Cs_xWO₃/SiO₂-SH nanoparticles into normal polymer-dispersed liquid crystals (PDLCs) film. The surface-modified SiO₂-SH helps not only to prevent the aggregation of Cs_xWO₃ nanoparticles in polar solvent, but also to maintain the well-dispersibility of Cs_xWO₃/SiO₂-SH nanoparticles in the prepared film. The results indicated that the samples doped with Cs_xWO₃/SiO₂-SH nanoparticles exhibited more dramatic electro-optical performance regulation effect than the samples doped with Cs_xWO₃ nanoparticles due to the synergistic effect of the enlarged void and the woken anchoring forces. The optical transmittance suggested that the sample containing 7 wt% Cs_xWO₃/SiO₂-SH nanoparticles can control the transmittance between 0.5 % and 71.2 % in the visible light, and shield more than 75 % NIR radiation. In the outdoor experiment, the temperature difference between two model houses consistently around 7 °C after 2 min exposure to the sun under the experimental conditions, suggesting the outstanding thermal management ability of the as-made film. The work could open new doors for the development of energy-saving smart windows in architecture and vehicle glass.