Effect of Yb concentration on the structures and upconversion luminescence properties of Y2O3:Er ultrafine phosphors

Y₂O₃:Er³⁺ ultrafine phosphors with a varying Yb³⁺ ion concentration were prepared by a urea homogeneous precipitation method. The results of XRD show that all the samples are of a pure cubic structure and the average crystallite sizes can be calculated as 45, 34, and 28 nm for Y₂O₃:Er³⁺ ultrafine phosphors with Yb³⁺ ion concentrations of 0, 10%, and 20%, respectively. The lattice constant and cell volume of the ultrafine phosphors decrease with enhancing Yb³⁺ ion concentration. The upconversion luminescence spectra of all the samples were studied under 980 nm laser excitation. The strong green and red upconversion emission were observed, and attributed to the ²H_11/2 → ⁴I_15/2, ⁴S_3/2 → ⁴I_15/2 and ⁴F_9/2 → ⁴I_15/2 transitions of Er³⁺, respectively. The intensity of red emission increases with increasing Yb³⁺ ion concentration. The effect of Yb³⁺ ion concentration on the structures and upconversion luminescence mechanism were discussed.     

Er3+掺杂位置对Er3+:BaTiO3薄膜上转换发光的影响

采用溶胶-凝胶法在LaNiO3/Si衬底上制备Er3+掺杂BaTiO3薄膜.通过XRD、AFM和PL图谱分别研究薄膜的晶体结构、形貌以及上转换发光性能.结果表明,薄膜的微观结构和发光性能与Er3+掺杂晶格的位置有关.A位掺杂薄膜较B位掺杂薄膜具有较小的晶格常数和较好的结晶.PL光谱表明:A位掺杂的薄膜和B位掺杂的薄膜都于528 nm和548nm处获得较强的绿色上转换发光以及在673 nm处获得较弱的红光,分别对应Er3+离子的2H11/2→4I15/2,4S3/2→4I15/2和4F9/2→4I15/2能级跃迁.相对于B位掺杂的薄膜,A位掺杂样品有较强的绿光发射积分强度以及较弱的红光发射相对强度.这种差异可以通过薄膜的结晶状况和交叉弛豫机制来进行解释.     

Er~(3+)掺杂位置对Er~(3+):BaTiO_3薄膜上转换发光的影响(英文)

采用溶胶-凝胶法在LaNiO3/Si衬底上制备Er3+掺杂BaTiO3薄膜。通过XRD、AFM和PL图谱分别研究薄膜的晶体结构、形貌以及上转换发光性能。结果表明,薄膜的微观结构和发光性能与Er3+掺杂晶格的位置有关。A位掺杂薄膜较B位掺杂薄膜具有较小的晶格常数和较好的结晶。PL光谱表明:A位掺杂的薄膜和B位掺杂的薄膜都于528nm和548nm处获得较强的绿色上转换发光以及在673nm处获得较弱的红光,分别对应Er3+离子的2H11/2→4I15/2,4S3/2→4I15/2和4F9/2→4I15/2能级跃迁。相对于B位掺杂的薄膜,A位掺杂样品有较强的绿光发射积分强度以及较弱的红光发射相对强度。这种差异可以通过薄膜的结晶状况和交叉弛豫机制来进行解释。     

Lu2O3: Yb3+, Tm3+纳米晶的水热法合成和上转换发光性能研究

采用水热法制备了Yb3+和Tm3+共掺杂的Lu2O3纳米晶。研究了前驱体溶液pH对纳米晶的结构、形貌和上转换发光性能的影响。实验结果表明:制备出的纳米晶具有纯的Lu2O3相,结晶性较好。在980nm半导体激光器激发下,样品发射出蓝光和红光,其发光的中心波长分别位于490和653nm。当前驱体溶液pH为9时,Lu2O3:2%Yb3+,0.2%Tm3+纳米晶上转换发光强度最强,这是因为Lu2O3:2%Yb3+,0.2%Tm3+纳米晶的尺寸最大,其表面吸附的OH-基团最少。发射强度与激发功率的关系表明,蓝光490nm和红光653nm的发光是三光子过程。     

Synthesis and upconversion luminescence properties of monodisperse Y2O3:Yb, Ho spherical particles

Monodispersed spherical Y₂O₃:Yb, Ho upconversion luminescence (UCL) particles with sizes of 40-200 nm are prepared using a homogeneous precipitation method. It is found that aging time, varying between 90 and 10 min, has a profound influence on the precursor size, which systematically decreases from 230 nm to 50 nm. The precursor shows poor stability when aging time is 10 min, and the stability of precursor can be improved by increasing the urea concentration. The UCL spectra of Y₂O₃:Yb, Ho with different particle sizes are investigated. The results indicate that the integrated emission intensity ratio of green to red (R_green/red) exhibits a gradual decrease from 2.7 to 0.45 when the particle size decreases from 200 nm to 40 nm, and the possible reasons are evaluated.     

Lu_2O_3:Yb~(3+),Tm~(3+)纳米晶的制备和上转换发光性能(英文)

采用碳酸氢铵(NH4HCO3)为沉淀剂,用共沉淀法制备Yb3+和Tm3+共掺杂的Lu2O3:Yb3+,Tm3+纳米晶。研究Tm3+摩尔分数、Yb3+摩尔分数和煅烧温度对Lu2O3:Yb3+,Tm3+纳米晶的结构和上转换发光性能的影响。结果表明:所制备的纳米晶具有纯的Lu2O3相,结晶性较好。当掺杂的Tm3+浓度超过0.2%(摩尔分数)时,出现浓度淬灭效应。Tm3+和Yb3+的最佳掺杂比分别为0.2%和2%(摩尔分数)。在980nm半导体激光器的激发下,样品发射出蓝光(490nm)和红光(653nm),分别对应Tm3+的1G4→3H6和1G4→3F4跃迁。发射强度与激发功率的关系表明,Tm3+的1G4能级布居是三光子能量传递过程。随着煅烧温度的升高,上转换发光强度增强,这主要是因为随着温度的升高纳米晶表面的OH?减少和纳米晶尺寸增大。     

EffectofEr~(3+) and Nd~(3+)doping on the luminescent properties of BaMgAl_(10)O_(17):Euphosphor

BaMgAl10O17:Eu blue phosphors were synthesized and the effect of doping er3+ and Nd3+ ions in the phosphor on the luminescent properties was investigated. When the content of Er3+ and Nd3+ ions is small, the phosphor remains single phase and the luminescent intensity of Eu2+ increases effectively. When Er3+ is doped, the shape of the excitation spectrum of the phosphor in the UV (ultraviolet) region remains unchanged. As Nd3+ is doped in the phosphor, the location and intensity of the two excitation peaks, and the emission intensity ratio excited by corresponding UV change dramatically owing to the alternation of crystal field splitting and level barycenter of 4f65d configuration of Eu2+ ion.     

Yb3+-and Er3+-doped Y2O3 microcrystals for upconversion photoluminescence and energy transfer with enhancements of near-ultraviolet emission

Yb3+and Er3+were doped into Y2O3 to form Y2O3∶Yb3+,Er3+microcrystals.The effect of doping concentration of Yb3+was studied.The near-ultraviolet(UV)upconversion(...     

Gd2O3：Yb，Er纳米材料的制备及上转换发光研究

利用Triton X-100／正己醇／环己烷／正己烷／水制成W／O微乳反胶团体系制备Gd2O3：Yb，Er上转换材料。利用扫描电镜观察氧化物粉体的颗粒形貌均为球形；通过改变掺杂元素Yb和Er的比例，在980nm的红外光激发下，观察研究氧化物颗粒的发光性质。该粉体在波长为980nm的半导体激光器激发下发射出绿色和红色的上转换荧光，分别对应于Er^3＋离子的。^S3／2／^2H11／2→^4I15／2跃迁和。^F9／2→^I15／2跃迁。     

Synthesis and Cathodoluminescent Properties of Y2O3: Eu3+ Phosphor with Micron-sized Controllable Particles

荧光粉的发光性能对其形貌非常敏感,特别是荧光粉的尺寸。场发射显示器所需的荧光粉应是微米级的球状,然而可控的微米级荧光粉受到很少的关注。因此,本实验通过改进的共沉淀法制备合成了几微米的近球型红色Y2O3:Eu3+荧光粉。该产品在1050℃,pH值为5.5时,形貌均匀,粒径分布为0.9~3.1μm,且发光亮度较商用的增加50%以上。结果表明,通过改良的共沉淀法可以制备出一种高质量的FED荧光粉。     

Preparation of Y2O3：Eu^3＋ phosphor by molten salt assisted method

A kind of fine and quasi-spherical Y2O3：Eu^3＋ phosphor was prepared by firing a preparative precursor at 1 200 ℃ for 2 h with the molten salts of Na2CO3, S and NaCl. The precursor was obtained by homogeneous precipitation of yttrium and europium with oxalic acid when using EDTA, citric acid or starch as complexant. The structure and morphology of the phosphors were characterized by XRD and SEM, respectively. The influence of complexing environment, firing temperature and molten salts on formation of the phosphor Y2O3：Eu^3＋ was discussed. The result show that the prepared Y2O3：Eu^3＋ phosphor is of quasi-spherical structure with size of 2-3 μm. Its luminescent intensity is 30% higher than that of the same phosphor prepared by the same procedure but without molten salts, and is 5% higher than that of commercial Y2O3：Eu^3＋ red phosphor.     

Synthesis of Y2O3：Eu^3＋ phosphors by surface diffusion and their photoluminescence properties

Y2O3:Eu3+ phosphors were synthesized by the surface diffusion method (SDM). X-ray diffractometry (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS) were used to characterize the structure, morphology and component of Y2O3:Eu3+ phosphors. The photoluminescent (PL) properties were also investigated. The results reveal that the PL intensity of Y2O3:Eu3+ phosphors prepared by the surface diffusion method (SDM) is much higher than that prepared by homogeneous co-precipitation. Th...     

Influence of La^3＋ and Dy^3＋ on the properties of the long afterglow phosphor CaAl2O4： Eu^2＋, Nd^3＋

The long afterglow phosphor CaAl2O4:Eu2+,Nd3+ was prepared by the high temperature solid-state reaction method,and the influence of La3+ and Dy3+ on the properties of the long afterglow phosphor was studied by X-ray diffraction (XRD),photoluminescence (PL),and thermoluminescence (TL),The XRD pattern shows the host phase of CaAl2O4 is produced and no impurity phase appears.The peak wavelength of the phosphor does not vary with La3+ and Dy3+ doping.It implies that the crystal field,which affects the 5d electron states of Eu2+ is not changed dramatically after doping of La3+ and Dy3+.The TL spectra indicate that the phosphor doped with La3+ or Dy3+ produces different depths of trap energy level.In the mechanism of long afterglow luminescence,it is considered that La3+ or Dy3+ works as trap energy level.The decay time lies on the number of electrons in the trap energy level and the rate of the electrons returning to the excitation level.     

Structure and upconversion luminescence properties of BaYF5:Yb, Er nanoparticles prepared by different methods

BaYF₅:Yb³⁺, Er³⁺ (BYF) upconversion (UC) luminescence nanoparticles have been prepared using co-precipitation and hydrothermal techniques, respectively. Two different fluoride sources were used to synthesize BYF by the hydrothermal method, and the sizes of the as-prepared spherical particles were about 30 nm (NH₄BF₄ as a fluoride source) and 100 nm (NH₄HF₂ as a fluoride source), respectively. While the nanoparticles prepared by the co-precipitation method are irregular, many clusters and agglomerates can be seen. The UC fluorescence has been realized in all the as-prepared BYF samples upon 980 nm excitation. It is found that their luminescence spectra depend strongly upon the preparation method. Factors affecting the upconversion fluorescent intensity have been also studied. The UC emission transitions for ⁴F_9/2-⁴I_15/2 (red), ²H_11/2-⁴I_15/2 (green) and ⁴S_3/2-⁴I_15/2 (green) in the Yb³⁺/Er³⁺ codoped BYF nanoparticles depending on pumping power have also been discussed.     

Synthesis and luminescent properties of Eu~(3+)-doped Na_(24)As_2W_(22)O_(83)

The Eu3+-doped Na24As2W22O83 phosphor has been prepared by solid state reaction from Na3AsO412H2O, Na2WO4 2H2O and WO3, and characterized by elemental analysis, infrared spectroscopy and powder X-ray diffractometry. According to the measurements with X-ray diffraction, this material belongs to orthorhombic system with its lattice constants: a = 1.4750 nm, b = 1.1944 nm, c = 1.1062 nm, it is consistent with space group D24-P212121 (No.19). The emission and excitation spectra were measured. The luminescent properties of Eu3+-doped Na24As2W22O83 and mechanism of energy transfer were discussed.     

Ce3+掺杂对GdAl3(BO3)4:Dy3+和GdAl3(BO3)4:Tb3+荧光粉发光性能的影响

用湿化学方法合成了Ce3 /Dy3 及Ce3 /Tb3 共掺GdAl3(BO3)4发光材料.利用X射线衍射仪对其进行了物相分析,结果表明:合成物为纯的六方相GdAl3(BO3)4微晶.利用荧光分光光谱仪进行光谱分析,测定了合成样品的激发和发射光谱.发现在紫外激发下,GdAl3(BO3)4:Dy荧光粉发射出很强的偏黄的白光,其发射峰分别位于480,575和665 nm,对应于Dy3 的4F9/2→6H15/2,13/2,11/2跃迁.掺Ce3 对Dy3 起到敏化作用,GdAl3(BO3)4:Dy,Ce发出很亮的暖白光,且强度是GdAl3(BO3)4:Dy的3倍左右.同时,在Ce3 /Tb3 共掺的样品中,由于Ce3 与Tb3 间的能量传递,Tb3 的541 nm特征峰显著增强.     

Synthesis and luminescent properties of Ln3+ (Ln3+ = Eu3+, Dy3+) -doped Bi2ZnB2O7 phosphors

The new phosphors Bi2ZnB2O7:Ln3+ (Ln3+ =Eu3+,Dy3+) were synthesized by solid-state reaction technique.The obtained phosphors were investigated by means of X-ray powder diffraction (XRD),photoluminescence excitation and emission spectra with the aim of enhancing the fundamental knowledge about the luminescent properties of Eu3+ and Dy3+ ions in the Bi2ZnB2O7 host lattice.XRD analysis shows that all these compounds are of a single phase of Bi2ZnB2O7.The excitation and emission spectra of Bi2ZnB2O7:Ln3+ (Ln3+ =Eu3+,Dy3+) at room temperature show the typical 4f-4f transitions of Eu3+ and Dy3+,respectively.The hypersensitive transitions of 5D0→7F2 (Eu3+) and 4F9/2→ 6H13/2 (Dy3+) are relatively higher than those of the insensitive transitions in Bi2ZnB2O7.It is conceivable that the Bi2ZnB2O7 structure provides asymmetry sites for activators (Eu3+,Dy3+).The optimum concentrations of Eu3+ and Dy3+ ions in Bi2ZnB2O7 phosphors are both x =0.05.     

Y2O2SO4: Eu3+ 亚微米棒的合成及发光性能

以Na2SO4和K2SO4为熔盐,采用熔盐法合成了一维Y2O2SO4:Eu3+亚微米棒。应用X射线衍射、扫描电子显微镜和光谱仪等方法对合成产物的晶体结构、形貌和发光性能进行表征。考察了烧结温度、Eu3+掺杂浓度对合成产物的晶体结构、形貌和发光性能的影响,结果表明,原料混合物在1100℃空气中煅烧2 h可合成纯相、表面光滑的Y2O2SO4: Eu3+亚微米棒,Y2O2SO4: Eu3+亚微米棒的长边大于10 μm,短边为500~800 nm。在270nm紫外光的激发下,Y2O2SO4: Eu3+亚微米棒呈红光发射,最强发射峰位于616 nm处,归属于Eu3+的5D0→7F2跃迁,Y2O2SO4: Eu3+亚微米棒Eu3+的最佳掺杂浓度为10mol%。     

Roles of crystal defects in the persistent luminescence of Eu^2＋, Dy^3＋ co-doped strontium aluminate based phosphors

The roles of different point defects in persistent luminescence of SrAl2O4：Eu,Dy phosphors were investigated. The research results showed that Dyer plays an important role in the persistent luminescence of SrA1EO4：Eu, Dy phosphors. It can serve as the electron trap of suitable depth for persistent luminescence. V~ does not serve as the electron trap of suitable depth, but its existence can increase the depth of electron traps. There is interaction between the Dy^3＋（ DySr ） and the Eu^2＋（Eu^x Sr ）, and only if the distance between the Dy^3＋（DySr） and the Eu^2＋ （Eu^x Sr） is close enough, the Dyer can work as an effective electron trap. The point defect of V＂ Sr can be hole trap, but the change of its density in crystal matrix does not arouse the obvious change of persistent luminescence.     

白光LED用Y3-xAl5O12：Ce3x＋材料发光性能的影响因素的研究

采用高温固相法,在氢氩混合气下还原制备了白光LED用荧光材料Y3-xAl5O12：Ce3x＋。研究了助熔剂用量、焙烧温度、保温时间等因素对材料发光性能的影响。研究表明,助熔剂用量、焙烧温度、保温时间对材料的发光性能影响较大,且均存在一个最佳值,当基质原料中Ce3＋掺杂量x为0.06,助熔剂用量为6%（质量）,焙烧温度为1300℃,保温时间为4 h时所得发光材料的性能最好。XRD测试表明,所制备的材料Y2.94Al5O12：Ce03.＋06属立方晶系。荧光光谱测试表明,在365 nm紫外光激发下,材料Y2.94Al5O12：Ce03.＋06呈现白光,其形成的宽带发射光谱的主发射峰波长分别约为427 nm和472 nm。