Kim Suhan, Cho Jinhan, Char Kookheon
School of Chemical & Biological Engineering, NANO Systems Institute, National Core Research Center, Seoul National University, Seoul 151-744, Korea.
Langmuir. 2007 Jun 5;23(12):6737-43. doi: 10.1021/la070003q. Epub 2007 May 4.
Thermally stable nanoporous organosilicate thin films were realized by the microphase separation of pore-generating polymers mixed with an organosilicate matrix to be antireflective coatings (ARCs), for which a thin film with a refractive index (n) of 1.23 for zero reflection is required. The refractive index of such nanoporous organosilicate films can be tuned from 1.39 down to 1.23 by incorporating nanopores within the films. With a nanoporous single layer with n approximately 1.23, the light transmittance of the glass above 99.8% was achieved in the visible range (lambda approximately 550 nm). To overcome the limitation on the narrow wavelength for high transmittance imposed by a single antireflective nanoporous thin film, bilayer thin films with different refractive indices were prepared by placing a high refractive index layer with a refractive index of 1.45 below the nanoporous thin film. UV-vis transmittance of a glass coated with the bilayer films was compared with nanoporous single-layer films and it is demonstrated that the novel broadband antireflection coatings in a wide range of visible wavelength can be easily obtained by the organosilicate bilayer thin films described in this study. Also, ARCs developed in this study demonstrate excellent AR durability owing to the hydrophobic nature of the organosilicate matrix.
通过将成孔聚合物与有机硅酸盐基质混合进行微相分离，制备出热稳定的纳米多孔有机硅酸盐薄膜，用作减反射涂层（ARC），对于这种涂层，需要折射率（n）为1.23的薄膜才能实现零反射。通过在薄膜中引入纳米孔，这种纳米多孔有机硅酸盐薄膜的折射率可从1.39调节至1.23。对于折射率约为1.23的纳米多孔单层薄膜，在可见光范围（波长λ约为550 nm）内，玻璃的透光率达到了99.8%以上。为了克服单一减反射纳米多孔薄膜对高透光率窄波长范围的限制，通过在纳米多孔薄膜下方放置折射率为1.45的高折射率层，制备了具有不同折射率的双层薄膜。将涂覆有双层薄膜的玻璃的紫外-可见透光率与纳米多孔单层薄膜进行了比较，结果表明，本研究中所述的有机硅酸盐双层薄膜能够轻松获得宽范围可见光波长的新型宽带减反射涂层。此外，由于有机硅酸盐基质的疏水性，本研究中开发的减反射涂层具有出色的减反射耐久性。
