In a study published in Matter, SONG Yanlin's lab from the Institute of Chemistry of the Chinese Academy of Sciences (CAS) and LI Mingzhu's lab from the Technical Institute of Physics and Chemistry of CAS designed a structurally colored radiative cooling film with a hierarchically porous nested structure (SC-RC film), which can preserve highly efficient subambient cooling performance and provide an appealing colorful appearance.
The SC-RC film was engineered to reflect sunlight across a broad range of wavelengths while exhibiting distinct reflective peaks at specific wavelengths. It resulted in brilliant structural colors without compromising cooling efficiency. The color can be adjusted by altering the diameter of colloidal nanoparticles.
The innovative design embedded colloidal photonic crystals into micropits, ensuring a confined assembly of nanoparticles and reducing defects associated with self-assembly. This process resulted in vibrant structural colors. In addition, the porous polymethyl methacrylate (PMMA) micropit framework provided protective support for colloidal photonic crystals that significantly enhanced the mechanical stability of the structural colors.
The production techniques including nanoimprinting, phase separation, and self-assembly used to create the SC-RC film are simple and scalable, making them suitable for a wide range of applications from urban architecture to vehicles.
The SC-RC film showed excellent radiative cooling performance: cooling surfaces by an impressive 21.2°C in sunlight and outperforming commercial-colored films. This film combined functionality with visual appeal, paving the way for a future where energy-efficient cooling and aesthetics design coexist harmoniously.
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