Er3+,Yb3+共掺杂NaY(WO4)2上转换荧光粉的制备及其发光性能

应用传统水热法合成出具有四方白钨矿结构的NaY(WO_4)_2微米颗粒及一系列Er~(3+)/Yb~(3+)共掺杂NaY(WO_4)_2上转换荧光粉。利用XRD、SEM、TEM、HRTEM、粒度分布和上转换发光光谱对样品的物相、形貌及上转换发光性能进行分析表征。结果表明,p H值对于制备具有同一形貌的纯相NaY(WO_4)_2微米颗粒发挥重要作用。随着pH值的升高,可以完成从八面体到拟立方体再到片状颗粒的形貌转变。在980 nm近红外光激发下,观测到525及553 nm处的强绿光发射,对应Er~(3+)的~2H_(11/2)→~4I_(15/2)与~4S_(3/2)→~4I_(15/2)跃迁,以及650~680 nm范围内的弱红光发射,对应Er~(3+)的~4F_(9/2)→~4I_(15/2)跃迁,且绿、红光上转换发射均属于双光子过程。此外,通过调节NaY(WO_4)_2∶Er~(3+),Yb~(3+)荧光粉中Yb~(3+)的浓度,可实现对绿光色度的有效控制。     

水热合成LuF_3∶Yb~(3+),Er~(3+)微晶及其上转换发射与温度传感特性（英文）

通过在不同pH值下的简易水热法合成不同Yb~(3+)离子(n_(Yb~(3+))/n_(Lu~(3+))=5%~15%)和Er~(3+)离子(n_(Er~(3+))/n_(Lu~(3+))=1%~5%)掺杂浓度的LuF_3∶Yb~(3+),Er~(3+)微晶荧光粉。发现pH值对正交相LuF_3∶Yb~(3+),Er~(3+)的合成起着关键作用。在980nm激发下,LuF_3∶Yb~(3+),Er~(3+)荧光体呈现出以523nm(~2H_(11/2)→~4I_(15/2))和539nm(~4S_(3/2)→~4I_(15/2))为中心的强绿光上转换(UC)发射以及以660nm(~4F_(9/2)→~4I_(15/2))为中心弱红光上转换发射。通过使用X射线衍射(XRD)和光致发光(PL)分析测定了最强发射强度的Er~(3+)和Yb~(3+)的最佳掺杂浓度。浓度依赖性研究表明,达到最强的绿光上转换发光时最佳掺杂浓度为10%Yb~(3+),2%Er~(3+)。通过改变泵浦功率来研究LuF_3∶Yb~(3+),Er~(3+)荧光粉UC发光机制。通过980nm二极管激光器在293~573K的范围内研究了在523和539nm处的2个绿光UC发射带的荧光强度比(FIR)的温度依赖性,发现在490K得到最大灵敏度约为15.3×10~(-4)K~(-1)。这表明LuF_3∶Yb~(3+),Er~(3+)荧光体可应用于具有高灵敏度的光学温度传感器。     

基于油酸辅助水热法制备NaLuF4:Ln3+及光谱性质

采用油酸辅助水热法合成了具有上下转换发光性能的NaLuF_4∶Ce~(3+)、NaLuF_4∶Ce~(3+),Tb~(3+)、NaLuF_4∶Yb~(3+),Tm~(3+)、NaLuF_4∶Yb~(3+),Er~(3+)以及NaLuF_4∶Yb~(3+),Er~(3+),Tm~(3+)荧光粉材料。X射线衍射(XRD)表征结果表明产物各个衍射峰与标准卡片PDF#27-0726较好的吻合,得到六方相NaLuF_4晶体。扫描电镜(SEM)显示产物形貌为六棱柱,由粒径分布图可知属于微米级材料。NaLuF_4基质中单掺Ce~(3+)时,研究掺杂浓度对样品发光性能的影响表明NaLuF_4∶0.09Ce~(3+)的发光强度最大。双掺Ce~(3+)、Tb~(3+)时,详细讨论了NaLuF_4基质中Ce~(3+)→Tb~(3+)的能量传递机制,可认为是偶极-四极作用。在980 nm激光激发下,增大Yb~(3+)的掺杂浓度可以使Er~(3+)的红(~4F_(9/2)→~4I_(15/2))/绿(~2H_(11/2)→~4I_(15/2),~4S_(3/2)→~4I_(15/2))光发射比例增大,Er~(3+)的红光和绿光发射过程均属于双光子发射,Tm~(3+)的蓝光发射过程属于三光子发射,并且NaLuF_4∶0.20Yb~(3+),0.005Er~(3+),0.005Tm~(3+)样品实现了白光发射(x=0.335,y=0.385)。     

Yb~(3+)共掺杂La_2Sn_2O_7:Er~(3+)上转换发光材料的水热合成与性能

利用水热法合成Yb~(3+)共掺杂La_2Sn_2O_7:Er~(3+)上转换发光材料,采用X射线衍射(XRD)、扫描电子显微镜(SEM)、傅里叶红外光谱(FT-IR)、紫外可见漫反射光谱(UV-Vis)和上转换发光光谱(UPL)对Yb~(3+)掺杂量对合成样品的上转换性能及反应体系pH对合成样品的物相结构进行分析。结果表明,反应体系的pH和Yb~(3+)掺杂量分别影响着所制备样品的物相结构和上转换性能。反应体系pH为13的水热环境下制备的样品为单一相烧绿石结构的La_2Sn_2O_7样品。上转换图谱分析结果表明,所制备的Yb~(3+)共掺杂La_2Sn_2O_7:7%(原子分数)Er~(3+)在980 nm的近红外光激发下在529, 550和665 nm处分别出现了Er~(3+)的上转换发射特征峰,并对Yb~(3+)共掺杂La_2Sn_2O_7:7%Er~(3+)样品的上转换敏化发光机制进行了分析,其中位于529 nm处的绿色光发射属于双光子吸收发光机制,且当Yb~(3+)掺杂量高于14%时观察到浓度猝灭现象。     

Er~(3+)/Yb~(3+)共掺杂La_2TiO_5荧光粉体的制备及上下转换荧光性质（英文）

使用溶胶-凝胶法制备了Er~(3+)单掺及Er~(3+)/Yb~(3+)共掺La_2TiO_5荧光粉体样品。经过1 100℃下3 h的煅烧,得到了较好的微晶。X射线粉末衍射测试表明样品中不含杂质相。扫描电镜观察表明样品颗粒范围为100~300 nm。紫外激发光谱中,在250~320 nm范围内出现Er离子和临近配位氧离子之间强烈的电荷转移跃迁峰,在350~500 nm出现Er离子f-f跃迁尖锐的吸收峰。在378 nm激发下,Er离子发射强烈的特征绿光(546 nm,~4S_(3/2)-~4I_(15/2)),当Er离子物质的量分数达到1%,发射峰强度达到最大。在980 nm激发下的上转换光谱中,Yb离子的共掺杂有效的敏化上转换发光强度。详细讨论了样品的上下转换发光机理及相应能量传递过程。同时测试了样品的荧光衰减和量子产率。     

Up-conversion Properties of Er~(3+)/Yb~(3+) Co-doped Li_3Ba_2Gd_3(MoO_4)_8 Phosphors

Er~(3+)/Yb~(3+)co-doped Li_3Ba_2Gd_3(Mo O_4)_8 phosphors were synthesized by conventional solid state reaction method,and their structure and spectral properties were investigated.The diffuse reflectance spectra showed that the ~4I_(15/2)→~4I_(11/2) transition of Er~(3+)and the ~2F_(7/2)→~2F_(5/2)transition of Yb~(3+)ions were highly overlapped.Under the excitation of 980 nm,three up-conversion(UC)luminescence bands around 530,555 and 660 nm were observed,corresponding to the~2H_(11/2)→~4I_(15/2),~4S_(3/2)→~4I_(15/2) and ~4F_(9/2)→~4I_(15/2) transitions of Er~(3+)ions,respectively.The effects of the concentration and pumping power on the UC intensities of Li_3Ba_2Gd_3(Mo O_4)_8:Er~(3+)/Yb~(3+)phosphors were investigated,and the possible UC mechanism was proposed based on the results.     

Yb^3＋和Er^3＋在Ⅲ—Ⅴ族半导体中的发光特性

在77K时观察到了离子注入Yb和Er的InP、SI—InP、GaAs和n—GaAs具有尖锐结构的光致发光峰。这些发光峰分别来自于Yb~(3+)(4f~(13))~2F_(5/2)→~2F_(7/2)(近1.0μm)和Er~(3+)(4f~(11))~4I_((13)/2)→~4I_((15)/2)(近1.54μm)的跃迁。注入Yb和Er的样品分别在800和750℃退火,获得最佳发光强度。根据光致发光和X射线双晶衍射回摆曲线的分析,InP:Yb样品在850℃退火,获得注入层的最佳晶格结构。本文首次研究了SI—InP中Yb~(3+)和Er~(3+)间的相互作用,并当SI—InP中Yb~(3+)和Er~(3+)的浓度相等时,观察到了Yb~(3+)和Er~(3+)的相互猝灭效应。     

Yb~(3+)/Er~(3+)共掺Gd_2Mo_3O_(12)的强绿色上转换发光及温度传感特性

采用固相反应法合成了Gd_2Mo_3O_(12):x%Yb~(3+)/1%Er~(3+)(x=0,2,5,10,20)荧光粉。当Yb~(3+)浓度超过5%,Yb~(3+)-MoO_4~(2-)二聚体形成并发挥敏化作用;当Yb~(3+)浓度达20%,二聚体敏化主导上转换发光。由于二聚体敏化抑制红光发射,成功获得高强度的绿色上转换发光。结合反射谱、拉曼谱、下转换谱、上转换功率关系、二聚体模型和三能级模型,详细讨论了这种和Yb~(3+)浓度有关的上转换发光。另外,基于两个绿光发射带的相对强度比,探究了最佳样品在300~500K范围内的温度传感特性,证实Gd_2Mo_3O_(12):Yb~(3+)/Er~(3+)在温度传感方面具有潜在应用价值。     

Er3+掺杂Li2O-SrO-ZnO-Bi2O3玻璃中Er3+离子在1.53 μm处的荧光发射特性

采用传统的熔融法制备了Er~(3+)掺杂的新型铋酸盐玻璃(Li_2O-SrO-ZnO-Bi_2O_3,LSZB),并对其光谱性质进行了表征,分析了玻璃的拉曼光谱、吸收光谱、荧光光谱,利用Judd-Ofelt理论研究了其荧光特性。LSZB玻璃样品中Er~(3+)的~4I_(13/2)→~4I_(15/2)跃迁发射峰位于1.53 μm处,半高宽约为78 nm。样品中Er~(3+)的~4I_(13/2)能级寿命为2.848 ms,量子效率为99.93%,受激发射截面达到9.76×10~(-21)cm~2。以上结果显示,Er~(3+)掺杂LSZB玻璃有良好的光谱特性。     

Er~(3+)和Ce~(3+)/Ce~(4+)掺杂β-BaB_2O_4纳米棒的制备、结构与发光性质

以Ba(NO_3)_2、NaBH_4、Er_2O_3和CeO_2为原料,在十六烷基三甲基溴化铵(CTAB)表面活性剂辅助下,采用水热法制备了β-BaB_2O_4(β-BBO)纳米棒,稀土离子Er~(3+)单掺杂的β-BBO(β-BBO:Er~(3+))及Er~(3+)和Ce~(3+)/Ce~(4+)共掺杂的β-BBO(β-BBO:Er(3+)/Ce~(3+)/Ce~(4+))纳米棒.通过X射线粉末衍射(XRD)、傅里叶变换红外(FTIR)光谱、拉曼光谱、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)和光致发光(PL)光谱分别对样品的物相、结构、形貌、成分及光致发光性质进行了表征.研究结果表明:微量稀土离子掺杂并不改变β-BBO的结构,制得的纳米棒尺寸均匀,长度在200-500 nm之间,直径在10-20 nm之间;β-BBO:Er~(3+)和β-BBO:Er~(3+)/Ce~(3+)Ce~(4+)纳米棒在400nm光激发下,在可见光范围内都观察到中心波长为515和542 nm的绿光.对发光机理的初步研究表明:发光分别对应于Er~(3+)的~2H_(11/2)→~4I_(15/2),~4S_(3/2)→~4I_(15/2)跃迁,铈离子以Ce~(3+)和Ce~(4+)两种形式存在于体系中,Ce~(3+)对Er~(3+)起敏化作用,可以显著增强β-BBO:Er~(3+)/Ce~(3+)/Ce~(4+)纳米棒的发光强度,存在Ce~(3+)→Er~(3+)的能量传递过程.     

Effect of Zn2+ Ions on Upconversion Emission of Er3+ in Zn/Er:LiNbO3 Crystal

The effect of Zn2+ ions codoped on the upconversion emission of Er3+ ions in Er:LiNbO3 crystal under different excitation wavelength was reported.The upconversion emission spectra of Zn/Er:LiNbO3 follo...     

Yb ion as a sensitizer for the upconversion luminescence in nanocrystalline Gd3Ga5O12:Ho

The effect of Yb³⁺ co-doping on the upconversion luminescence in nanocrystalline Gd₃Ga₅O₁₂:Ho³⁺ was examined. Strong and efficient NIR to green anti-Stokes luminescence was noted in nanocrystalline Gd₃Ga₅O₁₂:Ho³⁺, Yb³⁺ after excitation into the ²F_5/2 level of Yb³⁺ with 978 nm radiation. Weaker blue, red and NIR anti-Stokes luminescence was also observed after 978 nm excitation. An enhancement of the red ⁵F₅ → ⁵I₈ luminescence was observed in the anti-Stokes spectrum compared to the Stokes emission spectrum. This enhancement was attributed to two distinct energy transfer upconversion (ETU) mechanisms which preferentially populate the (⁵F₄, ⁵S₂) and ⁵F₅ levels.     

1.54 and 1.75 μm infrared luminescence of Y2O3:Er

A new 1.75 μm infrared emission transition of Y₂O₃:Er³⁺ is assigned to the ⁴S_3/2 → ⁴I_9/2 transition of Er³⁺ ions situated at the C₂ sites of cubic RE₂O₃ (RE = Y, Gd, Lu). The intensities of features in the 1.54 μm ⁴I_15/2–⁴I_13/2 absorption transition due to Er³⁺ at S₆ and C₂ sites are consistent with the site occupation ratio and the relative magnetic dipole–electric dipole intensity contributions of Er³⁺ at the different sites. The 1.54 μm emission lines are predominantly from Er³⁺ ions at C₂ sites. The different behaviours of the emission intensities 1.75 and 1.54 μm groups with change in Er³⁺ dopant ion concentration, preparation technique, Yb³⁺ co-doping, temperature change and different excitation line are rationalized.     

Studies on Upconversion Mechanism of ZrO2 ： Er^3＋, Yb^3＋ Nanocrystals Under Excitation at 488 and 980 nm

Erbium, Ytterbium-codoped ZrO2 nanoparticles(ZrO2:Er^3 ,Yb^3 ) were prepared by the sol-emulsiongel technique. The purpose of the present study is the application of upconversion phosphor in the biological label. In order to make out the mechanism of upconversion under 980 nm excitation the 488 nm pump was used. The influence of temperature on the crystallite phase was studied. The results confirm the upconverted mechanism in ZrO2:Er^3 ,Yb^3 nanocrystals is due to an energy transfer upconversion(ETU).     

Highly efficient blue up-conversion of Tm in Nd–Yb–Tm co-doped ZrF4-based fluoride glass

Up-conversion luminescence and energy-transfer processes in Nd³⁺, Yb³⁺ and Tm³⁺ co-doped ZrF₄-based fluoride glasses have been studied under 800 nm light excitation. Blue up-converted emission around 478 nm which can be assigned to the Tm³⁺:¹G₄→³H₆ transition, was strongly observed. Up-conversion luminescence intensity exhibited an YbF₃-concentration dependence. Among the Nd³⁺, Yb³⁺ and Tm³⁺, Nd³⁺ and Tm³⁺ have ground state absorption bands due to the (²H_9/2,⁴F_5/2)←⁴I_9/2 and ³F₄←³H₆ transitions, respectively, which can be directly pumped by 800 nm radiation. However, no emissions were observed in Tm³⁺ singly-doped and Tm³⁺–Yb³⁺ doubly-doped glasses under 800 nm excitation. Therefore, a possible up-conversion mechanism may be proposed as follows: energy-transfer firstly occurs from Nd³⁺ to Yb³⁺ when Nd³⁺ is excited by 800 nm light, then the energy is transferred from Yb³⁺ to Tm³⁺ which is in the excited state and, finally, blue up-conversion emission of Tm³⁺ is observed through the Tm³⁺:¹G₄→³H₆ transition.     

Ba3LaNa(PO4)3F:Tm3+, Dy3+: A tunable blue-white color emitting phosphor via energy transfer for UV white LEDs

A series of Tm^3+/Dy^3+co-doped Ba3 LaNa(PO4)3 F(BLNPF) phosphors were synthesized successfully via a high-temperature solid-reaction,and luminescence properties were investigated.Upon near violet excitation,BLNPF:Tm^3+,Dy^3+ phosphors exhibit Tm^3+:^1D2-^3 F4 and Dy^3+:^4 F(9/2)-^6 HJ(J=15/2,13/2,11/2)transitions with diffe rent luminescence intensity.The emitting color of the obtained products was found to shift from blue to white as a result of efficient energy transfer(ET) from Tm^3+to Dy^3+ions.According to photoluminescence emission intensity,the positive effect of activator on ET efficiency was calculated and the maximum ET efficiency was found around 72.6% with Dy^3+ concentration was 0.04.By means of Dexter's theoretical model,furthermore,dipole-dipole interaction was confirmed as the mechanism of energy transfer from Tm^3+ to Dy^3+ ions.The results suggested that BLNPF:Tm^3+,Dy^3+ phosphor might be a promising single-phased white-light-emitting phosphor for UV white-light LED.     

Studies on long lasting optical properties of Eu2+ and Dy3+ doped di-barium magnesium silicate phosphors

Di-bariummagnesium silicate phosphors doped with europiumand dysprosium were prepared under a weak reducing atmosphere. X-ray diffraction pattern of the sample was also done that confirmed the proper preparation of the phosphor. Scanning electron microscope (SEM) images confirmed that the sample has regular surface and uniform grain size distribution. Comparative studies of phosphorescence decay of Ba₂MgSi₂O₇:Eu²⁺, Dy³⁺ phosphors with different concentration of Dy³⁺ were done. The phosphor with 0.5/1.5 mol% of Eu/Dy, exhibited optimum green color afterglow properties. This emission is expected to arise due to transition of Eu²⁺ ions from any of the sublevels of 4f⁶5d¹ configuration to ⁸S_7/2 level of the 4f⁷ configuration. For a suitable trap depth, the trap concentration is expected to be proportional to the concentration of Dy³⁺. These traps are responsible for holding the charge career for a reasonable time, subsequently for increasing the time of afterglow. Hence, optimum Dy³⁺ concentration produces the longer afterglow duration with higher intensity of luminescence signals. Trap depth were also calculated using thermoluminescence glow curve which was indicative of formation of traps suitable for long afterglow.     

荧光粉Ba5-3x/2B4O11∶xEu3+的制备及发光性能

采用高温固相烧结法成功制备了Ba_5-3x/2B₄O₁₁∶xEu³⁺(x=0.02~0.22)荧光粉,利用XRD和SEM等对荧光粉进行了结构和形貌表征。 在激发波长为393 nm的条件下,发射峰(596、621、657和706 nm)与Eu³⁺的⁵D₀-⁷F_J(J=1,2,3,4)电子跃迁相对应,其中621 nm最强发射峰由Eu³⁺离子⁵D₀→⁷F₂电偶极跃迁造成。 文章还研究了Eu³⁺掺杂浓度对Ba_5-3x/2B₄O₁₁∶xEu³⁺发光性能的影响,结果表明,荧光粉的发光强度随着Eu³⁺掺杂量的增加呈现先增大后减小的趋势,Eu³⁺最佳掺杂量为0.16。     

Ba_3Y(PO_4)_3∶Dy~(3+),Eu~(3+)单基质白光荧光粉的制备与发光性能

为了探究在Dy~(3+)掺杂Ba_3Y(PO_4)_3荧光粉中共掺Eu~(3+)离子对其发光性能的影响,我们采用传统高温固相法制备了一系列Dy~(3+)、Eu~(3+)单掺杂和共掺杂Ba_3Y(PO_4)_3荧光粉。通过X射线衍射(XRD)、荧光发射光谱和荧光衰减曲线对样品进行了表征。结果表明,所制备的荧光粉呈闪铋矿立方相。在近紫外光激发下,Ba_3Y(PO_4)_3∶Dy~(3+)发射光谱在487和578 nm处有两个窄带发射峰,呈冷白光发射;Ba_3Y(PO_4)_3∶Eu~(3+)发射光谱的窄带发射位于594和616 nm处,呈发橙红光。在Ba_3Y(PO_4)_3∶Dy~(3+),Eu~(3+)中,由于Eu~(3+)离子补偿Dy~(3+)冷白光发射所缺的红色组分,从而实现了色纯度高、色温适中的暖白光发射。进一步探索了Ba_3Y(PO_4)_3∶Dy~(3+),Eu~(3+)荧光粉发光机理。所制备的Ba_3Y(PO_4)_3∶Dy~(3+),Eu~(3+)单基质白光荧光粉在白光近紫外激发白光二极管(UVWLED)领域具有潜在应用价值。     

High-temperature High-pressure Hydrothermal Synthesis of Dy3＋-doped YNbO4 Single Crystal and Its Luminescence Properties

Single crystal Dy3＋ doped YNbO4phosphors were prepared via a high-temperature high-pressure hydrothermal procedure. Under excitation at 270 nm, the Dy3＋-doped YNbO4 phosphor shows bright white emission, which is composed of two strong bands at 492 and 576 nm corresponding to the characteristic 4F9/2→6H15/2 and aF9/2→6H13/2 transitions of Dy3＋, respectively. The dominant band was observed at 352 nm, which corresponds to the 6H15/2→6p7/2 transition of Dy3＋. Nearly white light was achieved at 2ex 270, 310 and 388 nm and the CIE（International Commission on Illumination） values were （0.3135, 0.3421）, （0.3088, 0.3380） and （0.3146, 0.3296）, respectively.