Zinc oxide thin film prepared by sol-gel process for improving photoinduced hydrophilic property of glass

Abstract

Preparation of ZnO thin film coated on glass surface was investigated. ZnO thin films were prepared via sol-gel dip coating process using zinc acetate as a precursor. Types of solvent, concentration, withdrawal speed and calcination temperature conditions were varied to investigate their effect on transparency and photoinduced hydrophilic properties of the prepared thin films. Based on the experimental results, the ZnO thin films prepared with ethanol as the solvent, using zinc acetate concentration of 0.10 M at withdrawal speed of 3.0 cm/min and calcined at 500C could exhibit transmittance of above 90% in visible region and highly hydrophilic property with the water contact angle of 5 degree after UV irradiation for 30 min. Improvement of hydrophilic property of glass substrate was further investigated by variation of number of coating cycles. The improved hydrophilic property of ZnO thin films with the water contact angle lower than 5 degree after UV irradiation just for 10 min could be obtained.