Sol-Gel氧化硅减反膜的耐环境稳定性研究

Sol-gel derived antireflective (AR) coatings have presented extensive application in many fields such as optical components for high power lasers, solar glass and large screen display systems owing to their advantages of controllable refractive index, high laser induced damage threshold, low cost, high possibility of mass production and capability of large coating size. However, the sol-gel silica coatings have a high porosity that is more susceptible to be contaminated by absorption of contaminants from the environment, which reduces their AR efficiency and laser resistance. In this project, the fundamental research of sol properties and coating structures will be conducted to study the effect of sol structures and surface groups on the environmental stability of the AR coatings. Through the modification of the sol, functionalization of the coating surface and deposition of ultra-thin fluoride protective film, the sol-gel AR coatings with high environmental stability, laser resistance, solar radiation resistance and excellent AR efficiency would be successfully prepared. Thus it could provide a scientific solution to improve the durability and weatherability of lager scale AR coatings.

基于溶胶-凝胶（Sol-Gel）技术制备的SiO2减反膜由于具有可调的折射率、较高的激光损伤阈值、便于大面积镀膜、易于大规模工业化生产、成本低廉等优点，在高功率大型激光器用光学元件、太阳能电池用减反射玻璃、大屏幕显示系统玻璃等领域得到了广泛的应用。但Sol-Gel 氧化硅具有较高的孔隙率，使得其更容易吸附使用环境中的污染物，从而降低其光学性能和抗激光损伤特性，缩短使用寿命。本项目从溶胶特性和膜层结构的基础性研究入手，研究不同胶体结构、表面基团对减反膜耐环境稳定性的影响。通过对溶胶的改性、薄膜表面的功能化和超薄氟化物保护层的引入，获得具备较高耐环境稳定性、抗激光损伤性能、耐阳光辐照以及优异减反射性能的Sol-Gel减反膜制备参数。为大面积减反膜在延长使用寿命、增加耐候性等方面提供科学的解决方案。

溶胶-凝胶法制备的多孔SiO2减反膜由于具有可调的折射率、极高的激光损伤阈值、优异的光学性能、成本低廉、易于大规模生产等优点，在大屏幕显示系统、太阳能电池以及高功率激光系统等领域中有着广泛的应用前景。然而，Sol-Gel氧化硅薄膜的高孔隙率，使得其极易吸附环境中的污染物从而降低其光学性能和抗激光损伤特性，缩短使用寿命。本项目从溶胶特性和膜层结构入手，研究不同胶体结构、表面基团对减反膜耐环境稳定性的影响。采用OTMS，HTMS，KH570，HMDS等带有不同长链官能团的有机硅烷改性纳米二氧化硅颗粒，钝化了氧化硅颗粒表面，从而有效提高了薄膜的耐环境稳定性。在湿度大于90%的环境中放置2个月后，薄膜透过率下降低于0.3%，达到项目预期的效果。此外，使用HMDS，HTMS，OTMS等易挥发的气态有机硅烷分别与氨水气氛联合处理薄膜，使薄膜表面的羟基被长链官能团替代，薄膜的表面变得更为紧密，并且表面能变低，进而提高其环境稳定性。对比三种混合气氛处理的薄膜，HTMS与氨水气氛混合处理的薄膜在低真空油污环境中显示出最佳的稳定性，存放两个月后透过率未发生明显改变。氨水与HMDS联合处理的薄膜综合性能最佳，在潮湿环境中放置3个月后透过率几乎无变化；日光辐照11个月后透过率仅下降0.29%。该项目的开展为Sol-Gel氧化硅减反膜在增加耐候性、延长使用寿命方面提供了科学的解决方案。