Heat-Shielding and Self-Cleaning Smart Windows: Near-Infrared Reflective Photonic Crystals with Self-Healing Omniphobicity via Layer-by-Layer Self-Assembly

Abstract

Bioinspired photonic crystals that can be used to precisely control the optical reflection of light of a specific wavelength by varying their thickness and refractive index have attracted much attention. Among them, photonic crystals that can reflect near-infrared light have attracted attention owing to their potential applications including window coating with heat-shielding property. However, photonic crystals with an optical function in practical use sometimes lose their function because of contamination. Here, a near-infrared reflection coating film with self-healing omniphobicity was designed and prepared by layer-by-layer assembly and an instant liquid phase omniphobization method. The fabricated films had a self-cleaning thermal shielding effect. The films were visually transparent and could be used to control the reflection peak of the near-infrared light (range of 700-1000 nm) by adjusting the film thickness, which prevented the increase in temperature in enclosed spaces. After omniphobization, the films had self-cleaning properties of their surface and retained their optical properties. These functions are promising for practical application on windows as heat-shielding.

Rapid and economic fabrication approach of dielectric reflectors for energy harvesting applications

“…The prepared reflector suggested for the thermal shielding application, which was transparent for visible light and forbidding IR radiation. Although the prepared reflector had both capabilities, the choice of fabrication using the magnetron sputtering approach was expensive 35 .…”

Switchable Cavitation in Silicone Coatings for Energy‐Saving Cooling and Heating

“…[3,4] To decrease the impact of indoor heating and cooling on the environment, environmentally friendly and energy-saving alternatives are urgently needed. To date, several alternative technologies combining adaptive heating and cooling in one system have been developed, including smart windows, [5][6][7][8][9][10][11][12][13][14] Janus membranes, [15,16] and solar chimneys commercially available poly(dimethylsiloxane) (PDMS) precursor followed by curing in air ( Figure S1, Supporting Information). Similar to normal PDMS precursors, the emulsion needs about 6 days at room temperature to get fully cured, but could solidify within the first 20 min, accompanied by the fixation of the embedded water droplets.…”

Flexible core–shell CsxWO3-based films with high UV/NIR filtration efficiency and stability

“…More than 50% of the total energy is spent on air conditioning and heating, and a signicant amount of this energy is lost because of poor thermal shielding and/or insulation of windows. 2,3 However, normal window glasses cannot provide a shield against nearinfrared light in the solar energy spectrum, which increases the indoor temperature during summer. [4][5][6][7][8] It is well known that solar light is chiey concentrated in the wavelength range between 200 and 2500 nm, including ultraviolet (UV, a wavelength of 200 to 400 nm, 4% of total energy), visible (400-780 mm, 46% of the total energy), and near infrared (NIR, 780-2500 nm, 50% of total energy) light.…”