Transparent Conductive Indium Tin Oxides Films Coated On Optical Fibers Prepared By Liquid Phase Method

Indium tin oxide(ITO) thin film possesses excellent electric conductivity, visible-light transmittance and electromagnetic shielding ability, and is widely used for electronic components, which remains essential in modern electronic industry. Optical fibers coated with ITO film can help them acquire conductivity, transparency, gas sensitivity or other properties, so that can broaden their application in optoelectronic devices or sensors. In this research, a facile method to prepare optical fibers coated with ITO nanoparticle films was provided, and properties of as-prepared ITO powders and ITO coated optical fibers were also characterized.Firstly, ITO nano powders were prepared by hydrothermal process together with a post-annealing process. The effects of hydrothermal temperature and time on ITO nanocrystals were investigated. Hydrothermal time had no significant influence on ITO crystal, whereas hydrothermal temperature showed great effects. When hydrothermal temperature was 160℃,In(OH)3 was prepared after hydrothermal process. And In2O3 with cubic bixbyite structure was acquired after annealing process. When hydrothermal temperature was 180℃, In(OH)3 transformed into InOOH, In2O3 with both cubic bixbyite structure and rhombic corundum structure were acquired after annealing. When hydrothermal temperature reaches 200℃, all the In(OH)3 completely transformed into InOOH, and rhombic In2O3 crystals with irregular shape were formed after annealing process. Then ITO coated optical fibers were prepared by applying suspensions based on hydrothermal ITO powders as dip-coating precursor. The lowest resistivity of optical fibers coated with hydrothermal ITO was 0.8 Ω?cm, while transmittance reached 91.7%.Secondly, deep blue monodisperse ITO powders were prepared by one-step solvothermal process using ethylene glycol as solvent. The effects of solvothermal temperature and time on ITO nanocrystals were studied. When solvothermal temperature was reaches 220℃, ITO crystal started to be formed; ITO yields rose as solvothermal temperature was increased; when solvothermal temperature was beyond 250℃, ITO yields approximately trended to be stable. In terms of solvothermal time, ITO crystal started to be formed when solvothermally treated for 3h; crystal size of ITO increased as solvothermal time became longer, which followed the rules of Ostwald ripening. Then ITO coated optical fibers were prepared by applying suspensions based on solvothermal ITO powders as dip-coating precursor. The lowest resistivity of optical fibers coated with solvothermal ITO was 0.8 Ω?cm, while transmittance reached 93.1%.Eventually, the resistance of ITO films was decreased by 10 times as an improved sol-gel process was applied. The best resistance of 2.7*10-3 Ω?cm was achieved by doping 1.5 wt% of ITO powder into precursor sol. The photoelectrical performances of ITO coated optical fibers prepared by different methods were compared. The photoelectrical performance of ITO films based on ITO nanoparticle was not as good as that prepared by sol-gel method. However, the result of end luminance of ITO coated optical fibers showed that hydrothermal and solvothermal ITO coated optical fibers had better end luminance than sol-gel ITO coated optical fiers, which suggests that hydrothermal and solvothermal methods do less harm to optical fibers.