Nanoporous silica microspheres–ploymethylpentene (TPX) hybrid films toward effective daytime radiative cooling
Nanoporous silica microspheres–ploymethylpentene (TPX) hybrid films toward effective daytime radiative cooling
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DOI：
10.1016/j.solmat.2019.110301
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发表时间：
2020-03
影响因子：
6.9
通讯作者：
Yang Jingnan-;Xiangdong Gao;Yongqing Wu;Zhang Tongtong;H. Zeng;Xiaomin Li
中科院分区：
文献类型：
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作者：
Yang Jingnan-;Xiangdong Gao;Yongqing Wu;Zhang Tongtong;H. Zeng;Xiaomin Li
基于纳米多孔SiO2微球-聚4-甲基-1-戊烯（TPX）混合系统的超材料辐射冷却膜通过流延法沉积在氟掺杂氧化锡（FTO）基板上。考察了制备参数、薄膜厚度、SiO2/TPX体积比和微球尺寸对杂化薄膜结晶度、微观结构、光学透过率和红外发射率的影响。结果表明，TPX基体的结晶度受沉积温度的影响，杂化薄膜的微观结构受薄膜厚度的影响，50μm厚的薄膜表面呈现出多孔的微观结构。可见-近红外波段的光学透过率随着薄膜厚度和SiO2/TPX体积比的增加而降低，并且随着微球尺寸的减小而降低。杂化膜中SiO2微球的绝对含量决定了其透过率和散射效果。 8–13 μm 的发射率随着薄膜厚度和 SiO2/TPX 比率的增加以及微球尺寸的减小而增加。厚度为 50 μm、SiO2/TPX 比为 5%、微球为 8 μm 的薄膜在大气窗口中表现出高发射率（高达 0.91）和高选择性。集成最佳混合膜和银反射层的冷却装置在昼夜测试中表现出最低温度，比黑表面低约20°C，比镀银玻璃低12°C，比FTO样品低8°C。在夜间测试中，观察到相对于环境温度最大降低 4.5 °C。
The metamaterial radiative cooling films based on nanoporous SiO2microsphere-Poly-4-methyl -1-pentene (TPX) hybrid system were deposited on fluorine doped tin oxide (FTO) substrates via tape casting. Effects of the fabrication parameters, film thickness, SiO2/TPX volumetric ratio and microsphere size on the crystallinity, microstructure, optical transmittance and infrared emittance of the hybrid films were examined. Results show that the crystallinity of the TPX matrix is influenced by the deposition temperature, and the microstructure of the hybrid film is influenced by the film thickness, with the film of 50 μm thickness exhibiting porous microstructure on the surface. The optical transmittance in the visible-near infrared band decreases with the increase of the film thickness and the SiO2/TPX volumetric ratio, and with the decrease of the microsphere size. The absolute quantity of SiO2microspheres in hybrid film determines the transmittance and the scattering effect. The emittance at 8–13 μm increases with the increase of the film thickness and the SiO2/TPX ratio and with the decrease of microsphere size. The film with 50 μm thickness, 5% SiO2/TPX ratio and 8 μm microspheres exhibits both high emittance (up to 0.91) and high selectivity in the atmospheric window. The cooling device integrating the optimal hybrid film and silver reflective layer demonstrates the lowest temperature in the diurnal test, about 20 °C lower than the black surface, 12 °C lower than the Ag-coated glass and 8 °C lower than the FTO sample. In the nocturnal test, the maximum 4.5 °C reduction relative to the ambient temperature is observed.