【作者】 张晓明；

【导师】 罗姣莲；

【作者基本信息】 贵州大学 ， 电子科学与技术， 2018， 硕士

【摘要】 采用燃烧法,在不同温度（600℃、650℃、700℃、750℃）条件下制备得到Zn₃V₂O₈荧光粉材料,利用x射线衍射仪测定其晶体结构,用扫描电子显微镜观测其表面形貌,用荧光光谱仪测量其吸收光谱和发射光谱。结果表明在700℃条件下制备的Zn₃V₂O₈结晶度最好,在600℃和650℃制备的样品含有Zn₂V₂O₇杂相,Zn₂V₂O₇相的存在会减弱材料的发光性能。Zn₃V₂O₈呈宽带发射,发射宽度在400-700nm之间,550nm处达到峰值,基本上覆盖了整个可见光的范围。利用高温固相法制备了(Zn_1-x-x La_x)₃V₂O₈（x=0,0.001,0.01,0.1）系列荧光粉材料,研究表明掺杂量0.001mol制备的Zn₃V₂O₈:La荧光粉材料结晶度最好,且发光性能最强,随着掺杂浓度继续增大,(Zn_1-x-x La_x)₃V₂O₈的发光性能减弱。理论方面,基于密度泛函理论计算了Zn₃V₂O₈、(Zn_1-x-x La_x)₃V₂O₈、Zn₂V₂O₇、M₃V₂O₈（M=Mg、Sr）的能带、态密度、吸收谱、反射谱等。结果表明:Zn₃V₂O₈带隙宽度为2.715eV,光谱开始于可见光区域,在紫外和近紫外光区域有着良好的吸收。高压条件下可以减小Zn₃V₂O₈的禁带宽度,并增大了Zn₃V₂O₈对紫外及近紫外吸收。La的掺杂浓度对Zn₃V₂O₈光学性质影响很大,当La浓度增大到0.1 mol后其发光效率减弱。由于Zn₂V₂O₇中V与O原子的含量增加,导致V-3d与O-2p态增强,而它们又位于Fermi能级附近,导致禁带宽度减小,且在紫外-近紫外光区域,吸收系数小于Zn₃V₂O₈。对M₃V₂O₈（M=Mg、Sr）的电子结构和光学性能进行模拟计算发现,这些材料的发射光谱都位于可见光区域,能够充当良好的发光材料,相对Mg₃V₂O₈和Sr₃V₂O₈荧光粉材料,Zn₃V₂O₈在紫外和近紫外区域有着更好的吸收。更多还原

【Abstract】 The Zn₃V₂O₈ phosphor materials were prepared by the combustion method at different temperatures（600℃,650℃,700℃,750℃）.The crystal structure of the samples was determined by X-ray diffraction,and the surface morphology was measured by scanning electron microscopy.The excitation spectra and emission spectra were measured by fluorescence spectrometer.The results showed that the crystallinity of Zn₃V₂O₈ phosphor material prepared at 700℃was the best.The materials prepared at 600℃and 650℃contained Zn₂V₂O₇ heterophase.Zn₂V₂O₇ reduced the luminescent properties of the material.Zn₃V₂O₈ is broad-band emission,and the emission width is between 400-700nm,and the phosphor has the strongest emission peak at 550nm,basically covering the visible light range;phosphor materials of(Zn_1-xLa_x)₃V₂O₈（x=0,0.001,0.01,0.1）series were prepared by high temperature solid-state reaction method.It was found that when the La-doping was 0.001mol,the prepared Zn₃V₂O₈:La phosphor has the best crystallinity and the best luminescence properties.With the increase of La-doping,the luminescence of Zn₃V₂O₈:La decreases.The energy bands,density of states,absorption spectra,and reflectivity of Zn₃V₂O₈,(Zn_1-x-x La_x)₃V₂O₈,Zn₂V₂O₇ and M₃V₂O₈（M=Mg,Sr）have been calculated based on density functional theory.The results showed that the band gap width of Zn₃V₂O₈ was 2.715eV.The spectrum begins in the visible region and has good absorption in the ultraviolet and near ultraviolet regions.High pressure conditions have reduced the band gap of Zn₃V₂O₈ and increased the absorption of ultraviolet and near ultraviolet light by Zn₃V₂O₈.The La-doping has a great influence on the optical properties of Zn₃V₂O₈.when the La-doping was 0.001mol,the luminous efficiency of Zn₃V₂O₈ decreases.Comparing with Zn₃V₂O₈,the band gap of Zn₂V₂O₇ is reduced.The ratio of V and O atoms in Zn₂V₂O₇ increases,resulting in enhanced the V-3d and O-2p states near the Fermi level.At the same time,the absorption coefficient of Zn₂V₂O₇ is lower than that of Zn₃V₂O₈ in the UV-NUV region.The electronic structure and optical properties of M₃V₂O₈（M=Mg,Sr）were simulated and calculated.The results showed that the emission spectra of these materials were all in the visible region and can act as good luminescent materials.The Zn₃V₂O₈ has better absorption in the UV-NUV region than the Mg₃V₂O₈ and Sr₃V₂O₈ phosphor materials.更多还原