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稀土掺杂纳米发光材料的制备及发光性能的研究
The Synthesis and Luminescent Properties Investigation of Rare-earth Doped Nano-Phosphors
【作者】 杨宇明;
【导师】 杨桦;
【作者基本信息】 吉林大学 , 物理化学, 2009, 博士
【摘要】 随着场发射(FED)和等离子体(PDP)发光显示技术的发展,对荧光粉的粒度分布大小、稳定性、发光效率、发光亮度以及导电性等提出了更高的要求,由于纳米发光材料所具备的量子效应、表面效应以及小尺寸效应等优异的性能对其发光性能有显著的影响,因而已成为当前新型发光材料的研究重点。在众多纳米发光材料中,由于ZnO优越的特殊的光学性能,使得其成为了一种很有前途的光电子应用软件和光敏器件的候选材料;同时,以稀土硼铝酸盐为基质的发光材料亦具有良好的化学稳定性和热稳定性,因此,本文的重点是研究以硼铝酸盐和氧化锌为基质的掺杂稀土的纳米发光材料。本文综述了纳米发光材料的研究现状,系统介绍了镧系离子的光谱理论及镧系掺杂发光纳米微粒的研究背景,概括和评述了近年来镧系掺杂发光纳米微粒的合成和表面修饰所取得的进展及面临的问题,并对今后的研究方向进行了总结和展望。在此基础上,我们针对场发射显示器(FED)和等离子体(PDP)对发光材料的要求,以稀土硼铝酸盐和氧化锌纳米发光材料为研究对象,采用溶胶-凝胶法,水热法,热溶剂法,震荡法等方法成功制备了多种具有不同形貌和光学性质的稀土纳米晶。应用X射线衍射(XRD)、场发射扫描电镜(SEM)、光致发光光谱(PL)、能量弥散光谱(EDX)、发光衰减曲线和寿命等手段研究了合成条件和掺杂离子浓度等对稀土掺杂纳米微粒的晶体结构、形貌和尺寸、掺杂离子的固溶度和发光性能的影响,取得了一系列重要的结论和创新性成果,为稀土掺杂纳米发光材料成为一种极具发展前景的新型发光材料打下了坚实的基础。探索合成了SrAl2B2O7:Eu3+、SrLixAl2B2O7:Eu3+5%、SrNaxAl2BO7:Eu3+5%、SrAl2B2O7:Tb3+、SrAl2B2O7:Ce3+,Tb3+、YAl3(BO3)4:Eu3+,Dy3+、YAl3(BO3)4:Eu2+,Dy3+、YBO3:Eu3+,RE、ZnO:Eu3+体系,研究了稀土离子性质、浓度以及合成的温度和基质组成等因素对发光性能的影响。采用新的方法制备了ZnO纳米棒和纳米花,所制备的纳米棒尺寸均一,直径为65-85nm,长度为2μm。采用溶胶凝胶法、热溶剂法、水热法成功制备了不同形貌的纳米氧化锌,首次探讨了氧化锌的微观结构、形貌与宏观发光性能之间的关系。
【Abstract】 Along With the development of field emission(FED) and plasma light emitting display(PDP) technology,higher demands have been bring forward to phosphor particle size distribution,stability,light-emitting efficiency,brightness,as well as electrical conductivity.As for the nanophosphor materials quantum effect,surface effect,small-size effect and other excellent properties have great impact on their photoluminescence properties,which have come to be the research focus of the new nanophosphor materials.Among the many nanophosphor materials,ZnO has become to be a kind of promising optoelectronic applications and photosensor candidate materials due to its special optical performance;At the same time,the aluminoborate matrix also has good chemical stability and thermal stability, therefore the focus of this paper is to study the rare earth doped luminescent materials which use aluminoborate and ZnO as matrix.Along With the development of field emission(FED) and plasma light emitting display(PDP) technology,higher demands have been bring forward to phosphor particle size distribution,stability,light-emitting efficiency,brightness,as well as electrical conductivity.As for the quantum effect,surface effect,small-size effect and other excellent properties of the nanoluminescent materials have great impact on their photoluminescence properties;nanoluminescent materials have come to be the research focus of the new luminescent materials.Among the many nanoluminescent materials,ZnO has become to be a kind of promising optoelectronic applications and photosensor candidate materials due to its special optical performance;At the same time,the aluminoborate matrix also has good chemical stability and thermal stability,therefore the focus of this paper is to study the rare earth doped luminescent materials which use aluminoborate and ZnO as matrix.In this paper,the present status of nano luminescent materials are reviewed,lanthanide ion spectra theory and luminescence of lanthanide-doped nanoparticle research background are systematically introduced,summarized and reviewed the progress and the facing problems about lanthanide-doped luminescent nanoparticle synthesis and surface modification in recent years, and the future research directions are also summarized and prospects.On this basis,we aimed at the luminescent materials demands that requested by the Field Emission Display(FED) and plasma(PDP),regard rare earth doped aluminoborate and zinc oxide as research objects,a variety of rare earth doped nanocrystals that have different optic properties and morphologies have been successfully synthesized by sol-gel method,hydrothermal method, hot solvent method,vibration method etc..The impact of synthetic conditions and the doping ion concentrations on the rare earth doped nanocrystals crystal structure,morphology,size,doping ion solid solution and luminescent properties were studied by means of X-ray diffraction(XRD), field emission scanning electron microscope(SEM),photoluminescence spectroscopy(PL),energy dispersion spectroscopy(EDX),luminescence decay curves and life expectancy,a series of important conclusions and innovative results were acquired.Laid a solid foundation for the rare earth doped nanoluminescent material to be a new promising luminescent material. SrAl2B2O7:Eu3+、SrLixAl2B2O7:Eu5%3+、SrNaxAl2B2O7:Eu5%3+、SrAl2B2O7:Tb3+、SrAl2B2O7:Ce3+,Tb3+、YAl3(BO3)4:Eu3+,Dy3+,YAl3(BO3)4:Eu2+,Dy3+、YBO3:Eu3+,RE and ZnO:Eu3+ luminescent systems were synthesized.Studied the impacts of rare earth quality,concentration,synthesis temperature and matrix composition on the luminescent properties.The experimental results showed that the YAl3(BO3)4,YAl3(BO3)4:Dy3+,Eu3+、YAl3(BO3)4:Dy3+,Eu2+ samples are triangle crystal.The Al3(BO3)4:Eu2+,Dy3+ characteristic spectrum comes from the f-d transition of Eu2+.The codoping of Dy3+ intensified the fluorescence intensity, and it also mished the samples decay time.The best doping concentration of Oy3+ is 1.25%The same method was used to synthesize cubic systems of SrAl2B2O7 and SrAl2B2O7:Eu3+,M(M=Li+,Na+)、SrAl2B2O7:Tb3+、SrAl2B2O7:Ce3+,Tb3+.In the SrAl2B2O7:Eu3+ system,the best doping concentration is 5%.In the Sr0.96-xLixAl2B2O7:Eu3+(5%) system,the best doping concentration of Li+ is 7%. In the Sr0.96-xNaxAl2B2O7:Eu3+(4%) system,the strongest luminescent intensity was abtained when the 3%is chosen as the doping concentration of Na+.As for the SrAl2B2O7:Tb3+ samples,the best doping concentration of Tb3+ is 5%. The codoping of Ce3+ greatly intensified the emission band intensity.The samples fluorescent lifetime is also intensified.The single phase vaterite Y0.95-xBO3:Eu5%3+,Gdx3+ was synthesized using sol-gel menthod at 900℃air condition for 4h.Along with the increase calcination temperature,the crystal growth and the crystal is integrity,the fluorescent intensity is also intensified.The Y0.95-xBO3:Eu5%3+ fluorescent intensity is improved when the doping concentration of Gd is changed.The best doping concentration of Gd is 30%.YBO3:Eu3+,M(M=Na+,Li+,Ca2+,Ba2+,Sr2+,Al3+ samples were synthesized.The impact of different kinds to the samples fluorenscent intensity is discussed.The results showed that the order of sample fluorescent intensity is as follows:Li+>Na+>Ca2+>Al3+>vacancy>Sr2+>Ba2+.The samples luminescent intensity has close relations with the radius. The smaller radius of the codoping ions is,the stronger fluorescent intensity is got.At the same time,when the raius of the doping ions is smaller than Eu3+,the Y0.95BO3:Eu5%3+fluorescent intensity is intensified.But the Y0.95BO3:Eu5%3+fluorescent intensity is weaken when bigger radius ions were doped,which radius is bigger than Eu3+.Rare earth doped ZnO phosphors were also studied.For one thing,a new method- concussive method was used to synthesize ZnO及ZnO:Eu3+ nanorodsw. The optimal concussive frequency and reaction time are 750t/s and 24h respectively.The average diameter and length of the nanorods are 80 nm and 2μm respectively.The composing process and reaction mechanism are analysed, and the luminescent characteristics were also studied.Zinc oxide nanorods and zinc oxide nanoflowers were synthesized by new mentods,the dimention of the prepared nanorods are uniform with a diameter of about 65-75nm and a length of about 1.5μm.Different morphologies of zinc oxide and rare earth doped zinc oxide were successfully prepared via sol-gel method,thermal solvent method and hydrothermal method.The relationship between the microstructure and macroscopic luminescent properties were studied for the first time.The reaults showed that fluorescent intensity orders of the samples with different morphologies are as follows:nanorod arrays>nanoparticles membrane>nanoparticels>nanoflowers>nanorods.There are close relation ship between the samples properties and the homogeneous degree.The biger the samples homogeneous are,the stronger the samples luminescent intensity is.There are also close relation ship between the samples luminescent properties and the size of the sample diameters.The bigger the samlples diameter is,the stronger the samples luminescent intensity is.The samples homogeneous degree plays the decisive position between the two qualities.When two samples homogeneous degree are similar with each other,their luminescent degree will decided by their diameters.
【Key words】 Rare earth doped; nanophosphor material; luminescent intensity;