Study On Preparation Process Of ITO Thin Film By Electrospinning

Transparent conductive indium tin oxide (ITO) thin film has been widely used toprepare thin-film transistors, liquid crystal displays (LCD) and plasma displays etc,for its high conductivity and light transmittance. Electrospinning technique is asimple and efficient method in preparing micro-nano-fiber films. In recent years,electrospinning technique has obtained much attention for its unique advantages, suchas low-cost equipments and experiments, the large specific surface area of the fibers,and its wide applicability. In this paper, the ITO thin films with excellent optical andelectrical properties were prepared by electrospinning process.In this paper, the theorities of the agglomeration, dispersion and stability ofnano-particles in the liquid phase were firstly analyzed. Then the physical andchemical dispertion methods were respectively used to obtain the ITO suspensionwith good dispersion and stabilization. The optimum parameters were the stirringspeed600r·min^-1, the stirring time4h, the ultrasonic time3h, and the dispersingagent PVP1.5²g.Then, based on the preliminary experiment, the electrospinning nozzle wasimproved to increase the efficiency of the film-forming process by electrospinningprocess, and an efficient and air-assisted nozzle was designed. The parameters of thenozzle, such as its structure size and the gas-flow rate were also studied. Thecomparative experiments showed that the electrospinning efficiency of theair-assisted nozzle was ten times higher than that of the no-air-assisted nozzle, theefficiency of single air-assisted nozzle could reach to100g·h^-1, the ITO thin filmsprepared by the air-assisted nozzle had better uniformity and less defect too. Theoptimum parameters of the air-assisted nozzle were that the nozzle gap was0.2mmand the pressures on the air and suspension were1.5MPa and0.12MPa respectively.In order to improving the surface uniformity of the films prepared byelectrospinning technique, the repeated electrospinning and annealing process wasproposed, and the comparison experiments were made between the repeated electrospinning and annealing process and the one-step electrospinning and annealingprocess. The results indicated that, the surface uniformity of the films that preparedby repeated electrospinning and annealing process was better than that of the one-stepelectrospinning and annealing.Finally, the influence of the different temperatures and heat treatment time onthe ITO film's optical and electrical properties has also been studied in this paper. Theresults showed that the optimum heat treatment processing conditions of the ITOfilms that prepared by30minutes' electrospinning process were the temperature500℃and the time60min, the thickness100nm, the light transmittance80%, thesheet resistance80Ω^-1, and the resistivity8.25×10^-4Ω.cm.