This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: A window can admit welcome daylight but also let in unwanted heat, taxing air conditioning systems. Darkening the glass helps control glare, but the absorption of sunlight warms it.
An ideal window would block more incoming heat while also letting trapped heat escape. To address this challenge, researchers at the Chinese Academy of Sciences, Northeast Forestry University and collaborating institutions have developed a colorful smart window with a reflective silver layer that activates when a voltage is applied. The layer turns a tinted, see-through pane opaque, providing shade and privacy.
A separate outer coating helps the window release heat to the outside of the building. In outdoor tests, small structures covered by the prototype window stayed cooler than those covered by quartz glass or other commercial smart windows. The study, published in Nano Letters reveals a technology that manages daylight, privacy and heat at the same time.
The design accomplishes two complementary functions: reflecting incoming sunlight and shedding heat through infrared radiation. Even in its transparent state, the window's ultrathin layers reflect a substantial share of near-infrared sunlight, which adds heat without providing visible illumination. A silicone coating on the outside of the glass allows heat at longer infrared wavelengths to escape into the atmosphere.
For privacy, the application of a small voltage deposits silver from a gel onto an internal surface. This temporary layer increases sunlight reflection and makes the pane opaque. Reversing the voltage removes the deposited silver, restoring transparency.
In one tested design, average visible-light transmission fell from about 44% to below 5%. Near-infrared reflection rose from roughly 54% to 83%. The heat-emitting coating continued working in both states.
Extract — continue reading at the source.
