Preparation and characteration of polyvinyl butyral(PVB) doped organic-inorganic hybrid silica antireflective coatings

An organic-inorganic hybrid silica antireflective(AR) coating was prepared by base catalyzed sol-gel processes using tetraethylorthosilicate (TEOS) as precursor and polyvinyl butyral (PVB) as organic modifier. The structural, optical and morphological properties of the hybrid AR coating were investigated with FTIR, XRD, particle size analyzer, UV-Vis spectrophotometry, spectroscopic ellipsometry, atomic force microscope (AFM), and contact angle measurement. The results show that the structural property of the AR coating does not change with the addition of PVB. In the same experimental condition, maximum transmission occurs at 720 nm for normal AR coating, and the transmission reaches nearly 100% at 840 nm for PVB doped AR coating. The displacement of the maximum transmittance towards longer wavelength is due to higher thickness of the PVB doped AR coating. Compared to undoped silica coating, the contact angle of PVB doped AR coating increased from 29° to 71° indicating a higher hydrophobicity of PVB doped AR coating.