Jiefeng Li, Ming Fu, Heling Zhang, Chenhui Wei, Dawei He, Yongsheng Wang
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引用次数: 0
Abstract
Microspheres dispersed in composites exhibit excellent infrared emissivity for radiative cooling applications, which reflect sunlight and passively dissipate heat into space without electricity. In this study, hierarchical microspheres (HMs) with a two-tier structure, composed of SiO2, TiO2-coated SiO2, BaSO4, or PNIPAM, are incorporated into PDMS-based composites. These microspheres feature larger spheres assembled from submicrometer-scale nanoparticles and are fabricated via microfluidics to enhance radiative cooling performance. SiO2 HMs not only boost visible light reflection and exhibit structural color through a photonic stop band but also achieve an average emissivity of 97.55% in the atmospheric window. Both experimental and simulated results show that HMs enhance the emissivity performance of the composite material compared with solid SiO2 microspheres of the same diameter. Additionally, applying TiO2 coating to SiO2 HMs further increases the overall emissivity to 98.05%. Incorporating BaSO4 HMs also increased the average visible reflectivity to 96.56%, while maintaining superior infrared emissivity at 97.58%. The inclusion of PNIPAM spheres enabled temperature-responsive transmissivity, with the composite materials containing PNIPAM and SiO2 HMs preserving high infrared emissivity in the atmospheric window. These HM structures exhibit excellent solar reflectivity and thermal emission, making them effective for radiative cooling.
期刊介绍:
Advanced Optical Materials, part of the esteemed Advanced portfolio, is a unique materials science journal concentrating on all facets of light-matter interactions. For over a decade, it has been the preferred optical materials journal for significant discoveries in photonics, plasmonics, metamaterials, and more. The Advanced portfolio from Wiley is a collection of globally respected, high-impact journals that disseminate the best science from established and emerging researchers, aiding them in fulfilling their mission and amplifying the reach of their scientific discoveries.