3D porous polymer film with designed pore architecture and auto-deposited SiO2 for highly efficient passive radiative cooling. (March 2021)

• Record Type: Journal Article
• Authors: Xiang, Bo; Zhang, Rong; Luo, Yanlong; Zhang, Sheng; Xu, Lei; Min, Huihua; Tang, Shaochun; Meng, Xiangkang
• Is Part Of: Nano energy. Volume 81(2021)
• Publication Date: 2021-03
• Subjects: Passive radiative cooling -- 3D porous cellulose acetate -- Single-side auto-deposited SiO2 -- Solar reflectance -- Infrared emittance; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2020.105600
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Passive radiative cooling (PRC) is the most promising technique to address future cooling requirements as it cools a surface without any energy input by reflecting sunlight and radiating heat, which will have a great impact on the global energy landscape. Here, we report a significant advance toward the design and fabrication of a novel hybrid material for outdoor PRC based on three-dimensionally porous cellulose acetate (3DPCA) film with rationally designed pore sizes centered at ~5 µm and auto-deposited resonant polar dielectric SiO2 microspheres. The side of 3DPCA/SiO2 film with enriched SiO2 shows both ultrahigh average solar reflectance R ̅ solar of ~96% and enhanced average infrared emittance ε ̅ IR of ~95%, reaching up to the state-of-the-art levels. Especially the ε ̅ IR value is greater than that of the reported solid polymer film with randomly distributed SiO2 microspheres (93%). The excellent PRC capability is further demonstrated by outdoor tests where practically attainable cooling temperatures are ~8.6 °C for nighttime and ~6.2 °C for daytime. The performance equals or surpasses that of state-of-the-art PRC designs, while the developed technique offers paint-like simplicity for low-cost and large-scale production. Owing to its superior PRC capability and scalability, this composite film is of great potential for promoting radiative cooling as a viable energy technology. Graphical Abstract: ga1 Highlights: Rational design and fabrication of a novel type of PRC hybrid film is reported. The hybrid film achieves both ultrahigh R ̅ solar of ~96% and high ε ̅ IR ~95%. The hybrid film achieves a sub-ambient temperature drop of ~6.2 °C on daytime. The developed technique offers paint-like simplicity for diverse substrates.