| With the continuous development of nonlinear optical technology,the research of corresponding nonlinear optical materials has become more urgent.The most important of these is to develop new materials with better nonlinear optical properties or to develop new nonlinear optical properties of existed materials.As a molybdate material,zinc molybdate has more research on its luminescence properties,but less research on nonlinear optical properties.In this dissertation,the zinc molybdate nanomaterials with the lamellar structure were synthesized by hot water bath method,and then they were made into the form of organic glass,and their nonlinear optical properties were studied.From the results of study we found that zinc molybdate nanomaterials has certain potential applications in nonlinear optics.The main research contents of the dissertation as following:1.Preparation and characterization of zinc molybdate nanosheetsThe molybdenum oxide nanorods were prepared by a hot water bath method,and then the molybdenum oxide nanorods was combined with zinc acetate by a hot melt method.The ratio of hydroalcoholic,temperature of reaction,addition quality of zinc acetate and annealing temperature on the synthesis of zinc molybdate nanosheets were discussed.The morphology of the zinc molybdate nanosheets was characterized by SEM,XRD and TEM,and the molecular formula of zinc molybdate was determined to be Zn3[Mo2O9]by the way.The photoluminescence properties was studied by fluorescence spectroscopy at room temperature.The peak position of the excitation spectrum appeared at 433 nm,based on the excitation spectrum,the optical band gap size of zinc molybdate was calculated to be 2.86 eV,and the peak position of the emission spectrum appeared at 642 nm,emitting red fluorescence.2.Synthesis of the?Zn3[Mo2O9]?/PMMA organic glassThe prepared zinc molybdate nanosheets was ground to powder and then combined with methyl methacrylate?10.352 g?to prepare zinc molybdate nanosheet?Zn3[Mo2O9]?/PMMA with the catalyst of azobisisobutyronitrile?0.031 g?.Different mass of zinc molybdate nanosheets organic glass was prepared by controlling the addition quality of zinc molybdate nanosheets.We prepared zinc molybdate nanosheet organic glass respectively with mass of 4mg,6 mg,8 mg,and 12 mg,with a thickness of 1 mm,a length of 20 mm,and a width of 15mm.3.Nonlinear optical properties of?Zn3[Mo2O9]?/PMMA organic glassThe UV-visible absorption spectra of the above-mentioned zinc molybdate nanosheets organic glass with mass of 4 mg,6 mg,8 mg and 12 mg were tested respectively.It was found that the zinc molybdate nanosheets with a mass of 12 mg has the strongest linear absorption.Besides,the nonlinear absorption characteristics was studied by the open-hole Z-scan method.The mass of 4 mg zinc molybdate nanosheets organic glass was studied with the input energy50?J,55?J,60?J,65?J,70?J,and 75?J respectively.When the input energy was 50?J,it begin exhibited the characteristics of reverse saturation absorption,with the input energy increased,the reverse saturation absorption increased to saturation gradually.When the input energy reached to 75?J,the nonlinear absorption coefficient reaches the maximum value?=1×10–9 mW–1.Besides,determined input energy of 75?J,and the nonlinear optical test was performed on zinc molybdate nanosheets organic glass with mass of 4 mg,6 mg,8 mg and 12mg respectively.It was found that the highest nonlinear absorption with its mass of 6 mg,and the nonlinear absorption coefficient was?=1.83×10–99 mW–1.Moreover,the nonlinear absorption coefficient increased at first and then decreased with the increase of mass.The nonlinear absorption mechanism of zinc molybdate nanosheets was analyzed by the diagram of energy level structure,and a reasonable explanation was given for the all above conclusions.It was indicated that the zinc molybdate material is a nonlinear optical material with great potential. |
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