Synthesizing Of ZnO Nanomaterial And Analysision Of Optical Property

As an important semiconductor material with direct and wide band-gap（³.37eV） at room temperature, zinc oxide （ZnO） materials are applied widely inmany devices, for example light emitting diode （LED）, laser diode（LD）,radioprotective devices and high density integrated electronic devices. Due to aseries of special properties, such as high exciton binding energy, low growthtemperature, high hardness, good properties in gas sensor, chemical sensor andbiology sensor, non noxious and widely found in nature, it has potentialapplications in the many field. Structurally, morphologically and dimensionallycontrolled synthesis and large-scale, low-cost, patterned, designed growth arelikely very important parts of near-term research in ZnO nanostructures. BecauesIt is the key point to make ZnO material step forward to applications. Therefore,the improvement of preparation of ZnO nano-crystals and the investigation ofphotocatalytic activity were studied in this paper and the mechanism of crystalgrowth and photocatalytic reaction also was discussed.ZnO nanorods have been prepared by CTAB/hexane/isopropanol/Zn²⁺aqueous quaternary reverse micro-emulsion system. The effects of compositionand process factors on the morphology of the nanorods were investigated. Thesamples were characterized by XRD and SEM. The results indicated that thelength-diameter ratio of the ZnO nanorods can be controlled by Zn²⁺concentration and mole ratio of water and surfactant （W）. And the nanorodscome from accumulation of adsorbed nanocrystals after high temperaturecalcination but nanocrystals grow along a preferred direction.In this paper, Rod-like ZnO particles were synthesized via a polymercomplexation-sintering process by adding poly vinyl acetate （PVA） to the Zincacetate solution after calcination. The relationship between complex material，pHvalue of precursor solution，sintering atmosphere and the final products wasinvestigated. The crystal phase and morphology of the products werecharacterized by X-ray powder diffractometer （XRD） and scanning electronmicroscope （SEM）. Additionally, the structure of precursor solution was characterized by Fourier transform infrared Spectroscopy （FTIR）. Rod-like ZnObelongs to the hexagonal wurtzite system, with diameters and lengths of about100nm and1μm respectively were fabricated by PVA served as complexingmaterial with precursor solution`s pH value at8.5and sinteried under oxygenatmosphere. Experimental results showed that the ZnO assembly method isdetermined by the complexing material, the process of ZnO crystal growth canbe controlled by the pH value of precursor solution which through changing theZnO crystal growth units. The sintering atmosphere is a key factor to ensure theZnO crystal quality and remove the complexing polymer. The proposed facile,economically feasible, and allows coating of complex geometries synthesispromises future large-scale preparation of nanostructured ZnO for application innanotechnology.The photocatalytic activity of the samples with different pH value ofprecursor solution was tested. The results show that, ZnO has the very goodfunction of methyl orange degradation under ultraviolet radiation, which is agood candidate to degradate the organic pollutantions. The degradation ratereaches to80%after60mins irradiate. A good crystallinity and a large specificsurface area help elevate the photocatalytic activity. The amorphous layer exist atsample`s surface will reduce the catalytic efficiency obviously at the lowconcentration of methyl orange.