Design and preparation of SiO ₂/TiO ₂/SiO ₂-TiO ₂ antireflective coatings with excellent abrasion-resistance and transmittance via sol-gel process

Triple-layer broadband antireflective (AR) coatings with excellent abrasion-resistance and transmittance were designed using the theory of optical coating design. And the designed coatings were prepared on K9 glass via Sol-Gel process in this work. SiO ₂ and TiO ₂ sols were prepared using tetraethylorthosilicate (TEOS) and titanium tetraisopropoxide (TTIP) as precursors, respectively, and hydrochloric acid as catalyst. It is found that the average transmittance of the AR coatings over the entire visible region can reach 98.7%, which is 7.1% higher than that at the blank K9 glass. Moreover the transmittance of the AR coating does not obviously decrease after abrasion test, showing the excellent abrasion-resistance of the AR coatings. Hexamethyldisiloxane (HMDS) is further used to modify the surface of the AR coatings, which greatly improves the hydrophobicity of the coatings, and thus gives the AR coatings excellent environmental resistance.