具有超亲水光催化性能的λ/4-λ/2型两层宽频增透膜的制备和性能研究

λ/4-λ/2 Double-layer Broadband Antireflective Coatings with Superhydrophilicity and Photocatalysis

以多孔SiO_2/TiO_2复合膜为膜层材料,采用溶胶–凝胶法制备得到λ/4-λ/2型无峰两层宽频增透膜,此工艺制备过程简,单且对膜层折射率要求较低,镀制两层膜的K9基片在500～700 nm波段维持较高的透过率,在此区间透过率平均值为99.4%,在可见光区400～800 nm的平均透过率为99.0%。两层膜表现出优异的超亲水性能,在无需紫外光照的条件下,其在0.5 s的水接触角仅为2.2°,且超亲水性能能够维持超过20 d。同时,两层膜表现出一定的光催化降解有机污染物的能力。

Antireflective(AR)coatings,which can suppress the undesired interfacial Fresnel reflections,are widely used in optical devices and energy-related instruments.Conventional single-layer quarter-wave AR coatings,which only work at a single wavelength,have been seriously limited in some practical applications because of this inherent property.In this work,broadband AR coatings were designed and prepared based on the concept ofλ/4-λ/2 double-layer interference film by Sol-Gel dip-coating method.Substrates(K9 glasses)coated with the double-layer films attained consistent high transmittances at 500–700 nm with an average transmittance of 99.4%,and the average transmittance at visible region was 99.0%.Theλ/4-λ/2 broadband antireflective coatings were achieved without low-refractiveindex materials.So high-refractive-index TiO2 could be introduced into the double-layer films to endow the films with self-cleaning property.The double-layer films exhibited outstanding superhydrophilicity with water contact angle of 2.2°in 0.5 s,and the superhydrophilicity lasted for 20 d in the absence of UV illumination.The double-layer coatings also showed a good ability to decompose organic substances under UV irradiation.The broadband of AR coatings with photocatalysis and durable superhydrophilicity may be applied in the fields of opto-and microelectronics.