隨著科技不斷的創新與發展，使人們享有便利的生活，同時背後所付出的負擔卻是對於環境的浩劫。自18世紀工業革命以來，人類排放過多的溫室氣體，溫室氣體的產生會影響到地表溫度無法順利排熱至外太空，進而引發地表溫度日益增高的情況。為了改善此問題，可以透過二氧化矽在紅外線大氣窗口區域(8-13 μm)擁有很高的吸收與發射性質來解決全球暖化的問題發生。
本研究使用溶膠凝膠法的方式合成二氧化矽，使用此方式可以減少粒徑大小的標準差，避免造成不同顆粒大小有不同的輻射冷卻效果，經由改變pH值、溶劑比例、濃度的改變來控制粒徑大小與型貌的變化，並且比較不同變因之間對於吸收紅外線輻射能力的影響，最終於pH=11、100 ml 酒精與100 ml水的條件下合成0.1M 濃度的二氧化矽有最高的吸收度，因此，選擇此粉體與鐵氟龍膜進行混合，分別比較有無添加耦合劑過後的二氧化矽與表面覆蓋之間的關係，最後再測量其日照輻射冷卻的能力，其結果顯示可以於最高溫度時有效降低3.6°C。
各階段的實驗結果分別利用X光繞射儀(X-ray diffractometer, XRD)觀察粉體相組成，利用聚焦離子束顯微鏡 (Focus Ion Beam, FIB)探討顆粒表面並計算顆粒大小，使用傅立葉紅外線光譜(Fourier transform infrared spectroscopy, FT-IR)測量粉體吸收度的表現，最後也針對有無添加耦合劑的二氧化矽與覆蓋率之間的關係進行探討。

With the continuous innovation and development of science and technology, people enjoy a convenient life, while the burden behind it is environmental damage. Since the Industrial Revolution in the 18th century, it has emitted too much greenhouse gas. The production of greenhouse gases will affect the surface temperature that cannot be smoothly spread to outer space, which will cause the global temperature increase day by day. In order to improve this problem, the characteristics of high absorption and emission in the infrared atmospheric window area (8-13μm) of silica can be used to solve the problem of global warming.
In this study, the sol-gel method was used to synthesize silica. This method can reduce the standard deviation of the particle size and avoid the different radiative cooling effects on different particle sizes. This can be achieved by changing the pH value, solvent ratio and concentration. Control the changes on particle size and morphology, and compare the effects of different variables on the ability to absorb infrared radiation. Finally, 0.1M silica particles treated by the solvents of 100 ml ethanol and 100 ml Di-water at pH=11 has the highest absorption ability. Therefore, the powder was mixed with Teflon film, and the relationship between the silica powder and the surface coverage after the addition of coupling agent was compared. Finally, the solar radiative cooling ability was measured. The result showed that it can be effectively reduced by 3.6°C at the highest temperature.
The experimental results of each stage were used to characterize powder phase composition by X-ray diffractometer (XRD), and focused ion beam microscope (FIB) was used to explore the particle surface and calculate the particle size, and Fourier transform infrared spectrometer (FT-IR) measure the performance of powder absorption, and finally discuss the relationship between adding coupling agent silica and the coverage.

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