Research on Contamination-Resistant SiO 2 Optical Thin Films in a Vacuum Environment

The Contamination resistance of SiO 2 optical films prepared by using sol-gel method was investigated and improved in this research. FDTS (1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane) was used to modify SiO 2 thin films. Fourier Transform Infrared Spectrometer (FT-IR) and X-ray photoelectron spectroscopy (XPS) were used to evaluate the components on surface of the SiO 2 thin films. The optical properties and hydrophobicity were also measured. The results show that the SiO 2 thin film modification with FDTS causes −OH groups to be replaced by organic groups containing fluorine. The transmittance peak of SiO 2 thin film changes, and the surface contact angle of water droplets on the SiO 2 film increases from 35° to 107° after surface modification with FTDS. After the SiO 2 thin films had been put in a vacuum environment for 24 hours, the peak transmittance of the modified SiO 2 film under the same conditions is reduced to 0.14%, which is less than 3.17% of the unmodified film. The peak transmittance of the modified SiO 2 thin films is also improved.