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

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 x WO 3 /SiO 2 -SH nanoparticles into normal polymer-dispersed liquid crystals (PDLCs) film. The surface-modified SiO 2 -SH helps not only to prevent the aggregation of Cs x WO 3 nanoparticles in polar solvent , but also to maintain the well-dispersibility of Cs x WO 3 /SiO 2 -SH nanoparticles in the prepared film. The results indicated that the samples doped with Cs x WO 3 /SiO 2 -SH nanoparticles exhibited more dramatic electro-optical performance regulation effect than the samples doped with Cs x WO 3 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 x WO 3 /SiO 2 -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. • The PDLC film can control the visible transmittance and shield NIR shielding. • The surface modification of Cs x WO 3 /SiO 2 -SH endows the NPs organic properties improving the compatibility of composite system. • The Cs x WO 3 /SiO 2 -SH nanoparticles could shield the NIR shielding and remain transparent in visible region. • The film has the potential to be used as energy-efficiency smart windows.