LiCaPO4:Eu3+荧光粉的制备及其发光性能的研究

用溶胶凝胶法制备了Eu3+单掺LiCaPO4荧光粉,探究了Eu3+的掺杂浓度、退火温度对荧光粉发光性能的影响.实验结果表明,当反应温度为900℃、退火时间为2 h、Eu3+掺杂浓度为5mol％时,荧光粉发光强度最强.XRD结果表明,样品为六方晶系Ca3(PO4)2与LiCaPO4的混相.利用CIE进行计算,结果表明,E...     

YVO4：Eu^3＋，Bi^3＋荧光粉的制备及荧光性能研究

用溶胶凝胶法在较低温度下制备了YVO4：Eu^3＋，Bi^3＋荧光粉，采用X射线衍射仪（XRD），扫描电子显微镜（SEM）及荧光分光光度计测试，研究了合成产物的结构、表面形貌，分析了在Eu3’含量一定的情况下掺杂Bi^3＋的浓度的变化对发光性能的影响。结果表明，溶胶凝胶法合成的YVO4：Eu^3＋，Bi^3＋荧光粉为单相结构、粒径在1um左右、无团聚现象；Bi^3＋对Eu^3＋离子有敏化作用，在一定浓度下使荧光粉的发射强度增加。     

Li2 CaSiO4:Eu3+荧光粉的制备、结构及发光性能的研究

采用溶胶-凝胶法合成了Li2 CaSiO4:Eu3+系列荧光粉,并对其发光特性进行了研究.XRD图谱表明,合成的样品为纯相晶体.样品的激发光谱由Eu-O电荷迁移带和Eu3+的特征激发峰组成,在256nm激发下,样品的发射峰由Eu3+的5D0→7FJ(J=0,1,2,3)能级跃迁组成,随着Eu3+掺杂浓度的增大,样品出现...     

CaMoO4:Eu3+,Tb3+荧光粉的制备及其发光性能研究

本文通过燃烧法制备了Ca Mo O4:Eu3+,Tb3+荧光粉。通过在钼酸根基质中参杂不同浓度的Eu3+与Tb3+后得到了一系列样品,并对这些产品进行了XRD测试、荧光测试和CIE测试。XRD测试结果表明,样品为Ca Mo O4相;荧光测试结果表明,样品可以同时发出红、绿、蓝三基色的光;CIE测试结果表明,Ca Mo O4:1%Eu3+,5%Tb3+的CIE坐标坐落在近白光区域。因此,该样品具有很好的应用前景。     

白光发光二极管用荧光粉Ca0.5Sr0.5MoO4:Eu3+的制备及表征

采用以柠檬酸作为螯合剂的溶胶-凝胶法成功制备了新型纳米级红色荧光粉Ca0.5Sr0.5MoO4:Eu3+.通过X射线衍射、扫描电镜和荧光光谱等对该荧光粉进行了表征.结果表明:该荧光粉平均粒径为700 nm,在近紫外区395nm和蓝光区467nm光激发下都可发射出615 nm处的强烈红光,此外,Ca0.5Sr0.5MoO...     

溶胶-凝胶法合成YAl3(BO3)4:Eu3+荧光粉及其发光性能

以硝酸盐为原料、柠檬酸为配位剂的有机-无机杂化凝胶法合成掺Eu3 的四硼酸铝钇[YAl3(BO3)4:Eu3 ,YAB:Eu3 ]荧光粉.通过X射线衍射、扫描电镜和Fourier变换红外光谱、发光光谱测试,分析了不同温度下焙烧3 h所得粉体的物相、形貌与发光性质.结果表明:YAB:Eu3 的最低合成温度为1 000 ℃,在反应过程中,首先形成中间相Al4B2O9,YBO3和Y3Al5O12,而最终形成单相的YAB:Eu3 .1 100 ℃合成的晶粒尺寸比较均匀,平均粒径尺寸为108.2 nm.发光光谱的测试表明:在252 nm激发下,溶胶-凝胶法合成的YAB: Eu3 荧光粉最强发射峰位于612 nm处,属于Eu3 的5D0→7F2跃迁.Eu3 在YAB: Eu3 基质中的最佳掺杂摩尔分数为10%.     

CaMoO4:Eu3+红色荧光粉的制备及光谱分析

采用溶胶—凝胶法合成了CaMoO4:Eu3+白光LED用红色荧光粉。用XRD和荧光光谱对物相结构、发光性能进行了分析,XRD表明Mg2+,Sr2+,Ba2+部分取代Ca2+后,只有Sr2+的取代能形成连续固溶体;荧光光谱分析表明样品在220～490 nm范围内存在基质电荷迁移吸收带和Eu3+离子f-f跃迁吸收带两个较强的能量吸收带。通过光谱拟合分析了CaMoO4:Eu3+激发光谱能量吸收带的组成,研究表明通过选择不同的掺杂离子,从而改变吸收波长,可以制备出适应于不同激发波长LED芯片的荧光粉。     

Gd2O3:Eu荧光粉体的制备及其发光特性

分别采用溶胶-凝胶/燃烧合成结合法和共沉淀法合成了Gd2O3:Eu粉体,借助X射线衍射、扫描电镜、透射电镜、分光光度计等分析手段,对比研究了两种工艺制备Gd2O3:Eu荧光粉体的物相组成、形貌及荧光特性.结果表明:共沉淀法合成的Gd2O3:Eu为立方相;溶胶-凝胶/燃烧合成法制备的Gd2O3:Eu为单斜相.溶胶-凝胶/燃烧合成法制备的Gd2O2:Eu粉体蓬松、多孔,但存在一定程度的团聚.共沉淀法制备的立方相Gd2O3:Eu粉体在610 nm处呈现Eu2 的特征荧光;溶胶-凝胶/燃烧合成法制备的单斜相Gd2O3:Eu的发射波长产生红移,其中最强的2个发射峰起源于Eu3 的5D0→7F2跃迁,分别位于612 nm和621 nm.两种工艺制备Gd2O3:Eu粉体荧光特性的差异是由Eu3 在这两种粉体中所处晶格结构的对称性差异引起的.     

Eu2+掺杂的发光材料的制备及荧光性能

采用溶胶-凝胶法制备了系列Sr_2MgSiO_5:Eu~(2+)发光材料,并采用X射线衍射仪(XRD)、荧光光谱(PL)等测试方法对样品的物相结构和发光特性进行了表征及测试。研究结果表明:Sr_2MgSiO_5:Eu~(2+)发光材料中,加入少量Eu~(2+)离子后没有明显改变Sr_2MgSiO_5晶体结构,提高晶化温度有利于Sr_2MgSiO_5晶相的生成。当晶化温度为1150℃时,晶化时间为2 h,光谱强度最大Ba2MgSiO5:Eu~(2+)发光强度最佳。本文合成Sr_2MgSiO_5:Eu~(2+)发光材料可以应用到白光LED的技术中。     

NaGd(MoO4)2∶Eu3+红色荧光粉的制备及发光性能研究

本文采用溶胶凝胶法,以钼酸铵、硝酸钠、氧化钆、氧化铕作为原料合成NaGd(MoO_4)_2:Eu~(3+)红色荧光粉。利用XRD对所合成的荧光粉进行结构分析,通过荧光光谱探究了样品的发光性能。结果表明:当退火温度为900℃,稀土离子Eu~(3+)的掺杂浓度为8%时所制备的荧光粉具有最佳的发光效果。     

Luminescence and temperature-sensing properties of Y4GeO8:Bi3+,Eu3+ phosphor

In this paper, Y₄GeO₈:Bi³⁺,Eu³⁺ phosphor with dual emission centers was elaborated via conventional solid-state reaction technology. Thorough research on the structure, morphology, and luminous properties of Y₄GeO₈:Bi³⁺,Eu³⁺ phosphor, the potential applications in optical thermometry were investigated by means of fluorescence intensity ratio and thermochromic techniques. Under 290 and 347 nm excitation, Y₄GeO₈:Bi³⁺,Eu³⁺ phosphor presents broadband emission from ³P₁ → ¹S₀ transition of Bi³⁺ ions and characteristic emission peaks from 4f–4f transition of Eu³⁺ ions. Outstanding temperature-sensing capabilities are acquired from Y₄GeO₈:Bi³⁺,Eu³⁺ phosphor. The maximum relative sensitivity (S_r) can attain 1.51% K⁻¹ (λ_ex = 290 nm). With temperature raising (303–513 K), the emitted color of Y₄GeO₈:Bi³⁺,Eu³⁺ phosphor (λ_ex = 290 nm) shifts from faint yellow to red with a high chromaticity shift (0.180), which can be distinguished by the unaided eye clearly. Our results indicate that Y₄GeO₈:Bi³⁺,Eu³⁺ phosphor has potential applications in optical temperature measurement and high-temperature safety marker.     

Toward temperature-dependent Bi3+-related tunable emission in the YVO4:Bi3+ phosphor

Up until now, many previous works have indicated us that the photoluminescence (PL) properties of phosphors sometimes can be changed with the change in the external temperature, resulting in the anomalous PL phenomena and correlated new applications that are difficult to achieve at room temperature. In this work, we report the temperature-dependent Bi³⁺-related PL properties in the YVO₄:Bi³⁺ phosphor. Our findings show that increasing the temperature from 10 to 300 K enables manipulating the energy interaction from groups to Bi³⁺, thereby leading to the temperature-induced color tuning from blue (0.183, 0.212) to yellow (0.418, 0.490). Upon this heating process, we further reveal that the dynamic Bi³⁺ luminescence has experienced a regular transition from double-exponential to single-exponential decay, which results in the decrease in the average Bi³⁺ lifetime from 122.606 to 0.376 μs. Discussions on the PL results imply that the tunable PL observations are due to the interplay of temperature-dependent energy transfer from groups to Bi³⁺ and redistribution of the excited ³P₀ and ³P₁ states of Bi³⁺ upon the thermal stimulation. This work not only presents the temperature-triggered Bi³⁺ tunable properties in the well-studied YVO₄ host lattice but also can provide new insights into revealing Bi³⁺-related PL mechanism in other Bi³⁺-doped photonic materials in the future and, in the meanwhile, gives some directive ideas for us to explore previously unnoticed applications for rare-earth (RE; eg, Eu³⁺, Pr³⁺, Tb³⁺, Eu²⁺, Er³⁺, etc) and other non-RE (eg, Bi³⁺, Mn⁴⁺, Mn²⁺, Cr³⁺, etc) doped phosphors.     

Enhanced luminescence properties of Eu3+ in La2MoO6 by nonsensitization of Bi3+

It was unusual for Bi³⁺ ions to enhance the emission intensity of phosphors via nonsensitization. Here, La₂MoO₆:Eu³⁺, Bi³⁺ phosphors were successfully synthesized by a high temperature solid-state reaction method in air atmosphere. As the increase of doping concentration of Bi³⁺, the emission spectra of La₂MoO₆:Eu³⁺, Bi³⁺ phosphors had obvious shifts, splits and the enhancement of intensities, which indicated that the characteristics of the phosphors were modified. To analyze these phenomena, the crystal structure refinements, spectral characteristic analyze and Judd-Ofelt theoretical calculation were mainly performed. Bi³⁺ ions played the role of the nonsensitizer and affected the distortion of the crystal, the sites of Eu³⁺ ions, the field splitting energy and the internal quantum yield. Moreover the nephelauxetic effects of Bi³⁺ ions and the ET process caused synergistically the life times of La₂MoO₆:Eu³⁺, Bi³⁺ phosphors to increase and then gradually decrease. The CIE coordinates of phosphors changed within a small range. This study might be instrumental in promoting the further application of Bi³⁺ ions in rare earth luminescent materials.     

红色荧光粉YAl3(BO3)4:Eu3+的制备及发光性能研究

以稀土氧化物、硝酸铝和硼酸为原料,高温固相反应制备了单相红色荧光粉YAl3(BO3)4:Eu3+,用X射线衍射和发射光谱对荧光粉末的结构和发光性能进行了分析.研究了煅烧温度、Eu3+掺杂量对其发光性能的影响.结果表明,反应物在1 250 ℃下煅烧可制得单相YAl3(BO3)4:Eu3+晶体,在YAl3(BO3)4:Eu3+晶体中,Eu3+取代了YAl3(BO3)4晶体中Y3+,占据了非对称中心格位.在394 nm的紫外光激发下,YAl3(BO3)4:Eu3+荧光粉具有很强的发光性能,与(Y,Gd)BO3:Eu3+荧光粉相比,最强发射线波长由596 nm变为618 nm,由橙红色光变为红色光,色纯度有了很大提高.Eu3+的最佳掺杂量为8%(物质的量分数).     

SrMoO_4：0.05Eu~（3＋）,0.05Gd~（3＋）的制备及发光性能研究

分别采用化学沉淀法、微波法、水热法制备了SrMoO4：0.05Eu3＋,0.05Gd3＋荧光粉,并通过X-射线粉末衍射（XRD）、荧光光谱和扫描电子显微镜（SEM）对其晶体结构、荧光光谱和形貌进行了表征。结果表明：SrMoO4：0.05Eu3＋,0.05Gd3＋的结构属体心四方晶系;其宽激发带由Eu3＋-O2-、Gd3＋-O2-电荷迁移带和Mo6＋-O2-基质吸收峰组成,荧光发光以在616nm处Eu3＋的5 D0→7 F2跃迁引起的红光发光最强;254nm紫外光激发时,化学沉淀法制备SrMoO4：0.05Eu3＋,0.05Gd3＋的发光峰比SrMoO4：0.05Eu3＋的相应发光峰强度增大,这是由于Gd3＋向Eu3＋的能量传递敏化增强了Eu3＋的发光。     

Design of a defect-induced orange persistent luminescence phosphor BaZnGeO4:Bi3+

We report a novel bright orange persistent luminescence (PersL) phosphor BaZnGeO₄:Bi³⁺ with broad emission and PersL spectra. Its crystal structure, photoluminescence (PL) spectra, thermoluminescence (TL) spectra and PersL spectra were investigated in detail. The two emission bands at 440 nm and 595 nm originate from Bi³⁺ ions in normal Ba²⁺ sites (Bi1) and Ba²⁺ sites close to vacancy defects (Bi2), respectively. The introduction of and defects improves the emission intensity of Bi2 more than that of Bi1, demonstrating that Bi2 is related to the vacancy defects. The orange emission and PersL properties of BZGO:Bi³⁺ can be improved when a little and defects are introduced, because the introduction of and defects makes it easier for Bi³⁺ to enter in Ba²⁺ sites; and for PersL, and defects can perform as the effective trap centers to capture more charges, which is beneficial for PersL. BZGO:Bi³⁺ has quite good thermal stability, and the bright orange PersL can be observed by the naked eye for 1 h. Finally, a feasible PersL mechanism of BZGO:Bi³⁺ was proposed to clarify the PersL-generation process.     

水热法合成SrAl2O4:Eu2+,Dy3+长余辉材料

研究了SrAl2O4：Eu^2 ，Dy^3 长余辉材料的一种新合成方法。首先利用水热法制备出该发光材料的前驱体，然后将此前驱体粉体在还原气氛下高温烧结，得亮度高，余辉时间长的洲SrAl2O4：Eu^2 ，Dy^3 超细长余辉材料，并对其发光性能进行了研究。并对水热法和复合沉淀法合成的此种材料进行了比较。     

Enhancement of photoluminescence intensity of sintered CaAlSiN3:Eu2+ red phosphor-bismuthate glass composites

Wavelength converters in white light-emitting diodes are usually made by sintering of phosphor-glass powder compacts. An issue is that the sintering process usually results in the reduction of phosphor amount. In the present study, composites containing CaAlSiN₃:Eu²⁺ red phosphor and Bi₂O₃-B₂O₃-ZnO-Sb₂O₅ glass were fabricated by sintering method. Influences of CaAlSiN₃:Eu²⁺ phosphor content (10 vol%–30 vol%) and sintering temperature (410–430°C) on the residual amount of the phosphor phase and the resulting luminescence intensity of the composites were investigated. The change of CaAlSiN₃:Eu²⁺ content due to sintering was analyzed by X-ray diffraction. The interdiffusion between the CaAlSiN₃:Eu²⁺ and glass matrix was examine by scanning electron microscope equipped with energy dispersive X-ray spectrometry. This paper focuses on the change of luminescence intensity after sintering. It was found that although the content of phosphor CaAlSiN₃:Eu²⁺ reduces after sintering; the luminescent intensity of the composites anomalously increases. The optimum luminescence intensity is 14% higher than that of the as-mixed, unfired powder. It is proposed that the incorporation of Bi³⁺ ions from the glass matrix into the phosphor CaAlSiN₃:Eu²⁺ during sintering improves the luminescence ability of the phosphor particles.     

Synthesis and photoluminescence properties of a novel red phosphor SrLaGaO4:Mn4+

A novel Mn⁴⁺-doped strontium lanthanum gallate red phosphor SrLaGaO₄:Mn⁴⁺ has been successfully prepared via the conventional solid-state reaction method. Phase purity, photoluminescence excitation/emission spectra, concentration quenching, decay curves, and temperature-dependent photoluminescence have been investigated systematically. SrLaGaO₄:Mn⁴⁺ phosphor exhibits broad excitation band from 250 to 600 nm and emits intense red light centered at 716 nm arising from spin-forbidden transition, ²E → ⁴A₂ of Mn⁴⁺. The optimal dopant concentration of Mn⁴⁺ is determined to be 0.2 mol%. Dipole-dipole interaction is supposed to be the mechanism of concentration quenching. The crystal-field strength Dq, the Racah parameters B and C, and the nephelauxetic ratio β₁ of SrLaGaO₄:Mn⁴⁺ have been calculated according to its luminescent spectra. Our systematic investigation on this new phosphor can provide a reference for the development of red-emitting phosphor.     

Eu3+在LiSrPO4中的发光及浓度猝灭机理

采用高温固相法合成了白光发光二极管用LiSrPO4:Eu3+红色荧光粉.测量了LiSrPO4:Eu3+的激发和发射光谱,结果显示材料的发射光谱为一系列尖峰,主峰位于616 nm,具有很强的红光发射;激发光谱中O2-→Eu3+的电荷迁移态CTS (220～310 nm)非常低,Eu3+的f→f (310～500 nm)跃迁吸收很强,主峰位于393 nm,与InGaN(350～410 nm)管芯匹配.比较了LiSrPO4:Eu3+与LiCaPO4:Eu3+、LiBaPO4:Eu3+发射光谱的差异,这三种晶体中Eu3+占据的格位对称性按Ca、Sr、Ba顺序逐渐增加.根据Dexter理论判定Eu3+在LiSrPO4中的浓度猝灭机理为电四极-电四极(q-q)相互作用.加入电荷补偿剂Li+、Na+和Cl 均提高了LiSrPO4:Eu3+材料的发射强度.LiSrPO4: Eu3+是一种适合白光发光二极管激发的红色荧光粉.