Design And Synthesis Of Functional Materials

The master's thesis is divided into three sections:1)The phosphors of rare earth ions doped?-BaB₂O₄,?-BaB₂O₄:RE³⁺(RE³⁺=Eu³⁺,Tb³⁺),were synthesized by solid state reaction,and characterized by XRD,ICP,PL spectra and fluorescent lifetime.XRD indicated that though all of the lines were redshift owing to parts of Ba²⁺replaced by RE³⁺ions,the basic structure of?-BaB₂O₄had not changed.The optimum ions doping concentrations(Eu³⁺:20.60 mol%,Tb³⁺:9.20 mol%)were obtained by studying the relationship between fluorescence intensity and ion doping concentration.The spectrum tests showed that the maximum absorption spectrum was around 393 nm,the strongest emission peak was around 610nm for?-BaB₂O₄:Eu³⁺;For?-BaB₂O₄:Tb³⁺,the maximum absorption and emission spectrum were 278 nm and 542 nm,respectively.The CIE values of the best red and green phosphors were?x=0.6659,y=0.3341?and?x=0.2658,y=0.7243?separately.The CCT values were Tc=6413K and Tc=2909K,respectively.These results indicated that both phosphors have a good color purity.We also studied the effect of flux on the synthesis of phosphors,and found that the flux could enhance the luminescence intensity of phosphors greatly and improve the crystallinity of phosphors.2)It is known that SrTiO₃ is a good photocatalyst.Being the band gap is 3.4eV,the light-absorbing of SrTiO₃ is located on the ultraviolet region.In order to expand its absorbance range,the hybird of SrTiO₃/Fe₂O₃ was synthesized by intersurface redox reaction method.The prepared samples were characterized by XRD,HRTEM,EDS,PDOS,DRS,respectively.DRS data indicated that the absorption range of SrTiO₃/Fe₂O₃ samples was around 200 nm to 600 nm.The synthesized SrTiO₃ and SrTiO₃/Fe₂O₃ were applied to water splitting test,the results indicated that the hydrogen production rate of SrTiO₃ and SrTiO₃/Fe₂O₃ under UV irradiation reached up to 6.5 and 9.8 mmol·g^-1·h^-1,respectively.However,the values were down to 1.1and 2.9 mmol·g^-1·h^-11 when under visible light.Experiments confirmed that SrTiO₃/Fe₂O₃ can enhance the harvesting of solar light and improve the efficiency of photocatalytic water splitting.3)NBBF has laminar structure,and that the levels are linked by Na⁺which makes it has greater interlayer spacing.The structure of six-member rings in the layer connect to each other by B-O bond or Be-O,which forms an infinite plane structure.The stable layered structure may benefits the transfer of lithium ion or sodium ion,which may make NBBF acts as electrode materials for battery.We synthesized NBBF by hydrothermal method,and characterized its structure and morphology,measured its SHG effect,initial discharge capacity and current density.Further research is underway.