提高CaCO_3∶Eu~(3+),Li~+橙红色荧光粉发光性能的研究

为了提高CaCO3∶Eu3+,Li+橙红色荧光粉发光性能,采用硼酸作助熔剂,通过高温固相法合成了橙红色荧光粉CaCO3∶Eu3+,Li+,其结构属于方解石型CaCO3结构。CaCO3∶Eu3+,Li+的主激发峰位于275 nm,主发射峰位于595 nm附近,对应于Eu3+的5D0→7F1跃迁,发射橙红色光。研究了激活剂Eu3+、敏化剂Li+及助熔剂H3BO3的浓度对样品发射光谱的影响。结果表明,CaCO3∶Eu3+,Li+中Eu3+、Li+和H3BO3的最佳浓度分别为2%、8%和3%。3%H3BO3的加入,将相对发光强度提高了165%。     

助熔剂H3BO3对SrAl2O4:Eu2+,Dy3+长余辉发光材料性能的影响

通过低温燃烧法合成的方法,研究了不同掺入量配比的助熔剂H3BO3对Sr Al2O4:Eu2+,Dy3+长余辉发光材料性能的影响。结果表明:助溶剂促进了Sr Al2O4纯的单相晶体的形成,提高了激活剂Eu2+、Dy3+进入晶格的数量,提高了发光材料的发光性能。当H3BO3的掺入量达到0.6%时,余辉时间最长达到640 s,初始亮度也达到1.98(cd·m-2),发光性能最佳。     

用于白光LED的荧光粉Sr3MgSi2O8:Eu2+的发光特性

使用高温固相法制备不同NH4Cl(作为助熔剂)加入量和不同Eu2+浓度的Sr3MgSi2O8:Eu2+,并研究其成相和发光性质.研究结果表明:NH4Cl加入量为24%时,样品为纯相,发光最强.Sr3MgSi2O8:Eu2+样品在近紫外区存在强激发带(250～400 nm),谱峰位于366 nm相应的发射谱带位于蓝光区(420～500nm),为一个不对称宽带,谱峰位于457 nm,该发射带由两个发射峰组成,其位置较接近,因此不能复合出白光,Sr3MgSi2O8:Eu2+仅适合作为紫外LED芯片激发的蓝光荧光粉.     

蓝光激发锡酸盐红色荧光粉的光谱性能

采用高温固相法合成了Sr2-xSnO4∶Eu3+x系列红色发光粉,该荧光粉属于四方晶系结构。以465 nm的蓝光激发样品,Sr2-xSnO4∶Eu3+x荧光粉发射红光,以Eu3+的5D0-7F2电偶极跃迁发光最强。该材料能非常好地吸收465 nm波长的光。研究了激活剂Eu3+的浓度对Sr2-xSnO4∶Eu3+x样品发光性能的影响。结果表明,Eu3+的最佳掺杂浓度为5%。     

白光LED用LaPO4:Eu3+红色荧光粉的合成与表征

利用水热法制备了性能稳定的红色荧光粉LaPO4:Eu3+,同时研究了不同的Eu3+浓度、煅烧温度对荧光粉发光性能的影响.通过X射线粉末衍射(XRD)和扫描电子显微镜(SEM)来表征荧光粉的晶体结构和颗粒大小及形貌;用激发光谱和发射光谱以及荧光衰减曲线来表征荧光粉的荧光性能.结果表明:未煅烧时前躯体主要是六方晶相LaPO4·0.5H2O,煅烧温度在900℃时,所制备样品为单斜相LaPO4:Eu3+;SEM图像显示5 at.%Eu3+掺杂LaPO4呈椭球形,颗粒长约为500 nm,宽约为300 nm.最大发射波长和激发波长分别为592 nm和393 nm,发射光谱中592 nm和612 nm的发射峰对应的是Eu3+离子的5D0→7F1和5D0→7F2跃迁.其荧光寿命为3.32 ms.     

掺杂离子对红色荧光粉NaLn_4(SiO_4)_3F∶Eu~(3+)(Ln=La,Gd,Y)发光性能的影响

利用高温固相法合成系列Na Ln4(Si O4)3F∶Eu3+(Ln=La,Gd,Y)红色荧光粉,用X射线粉末衍射仪和荧光分光光度计对荧光粉进行结构和性能表征,研究Eu3+浓度以及基质组成的变化对Na Ln4(Si O4)3F∶Eu3+(Ln=La,Gd,Y)发光性能的影响。在394 nm激发下,荧光粉Na La4-x(Si O4)3F∶x Eu3+中的Eu3+主要体现5D0→7F2(616 nm)和5D0→7F1(590 nm)跃迁发射,而且5D0→7F2和5D0→7F1跃迁发射强度比例随Eu3+浓度的增大而变化,较低浓度时5D0→7F1发射比5D0→7F2强,较高浓度时则刚好相反。在273 nm激发下,荧光粉Na La3.9-yGdy(Si O4)3F∶0.1Eu3+或Na La3.9-zYz(Si O4)3F∶0.1Eu3+中Eu3+的5D0→7F2(616 nm)发射随掺杂离子浓度增加而增强,而5D0→7F1发射强度变化不大。因此可以通过改变Eu3+浓度以及基质组成离子Gd3+或Y3+浓度对5D0→7F2和5D0→7F1发射强度加以调整,进而调整荧光粉的红光色度。     

稀土掺杂荧光材料CaMoO4:Eu3+的制备及发光性研究

以钼酸铵、硝酸钙和三氧化二铕为原料,通过化学沉淀法制备稀土掺杂的发红光材料CaMoO4:Eu3+,并利用X射线衍射、激发发射光谱对粉体的结构、发光性能进行了表征.实验结果表明,在反应溶液pH值为7、反应温度为60℃、烧结温度为900℃、掺入物质的量分数为25%的Eu3+的工艺条件下制备了质量性能优良的CaMoO4:Eu3+粉体.该荧光粉可被394 nm的紫外光和465 nm的可见蓝光有效激发,发射光谱在616 nm处发光强度最大,是以电偶极跃迁5D0→7F2为主导地位的红光发射,CaMoO4:Eu3+粉体是一种可能应用在白光LED上的红色荧光材料.     

助熔剂对微波合成Y2O3:Eu3+红色荧光粉的影响

采用微波法合成Y2O3:Eu3+红色荧光粉,研究了碳酸盐、氟化物、硼酸等助熔剂对其合成过程及发光性能的影响.分别采用光谱分析仪和激光粒度仪对所合成荧光粉的光电性能和粒径进行分析.结果表明,不同助熔剂的加入对样品发射主峰的位置(610 nm)没有产生影响,但可明显影响样品的发光性能和粒径.采用碳酸盐单一助熔剂时,样品的相对亮度比采用氟化物时的高;采用复合助熔剂所制备样品在相对亮度及粒径方面,整体上较采用单一助熔剂样品的更优.     

助熔剂对BAM:Eu2+荧光粉合成机理和发光强度的影响

采用高温固相法制备了BaMgAl10O17:Eu2+ (BAM:Eu2+)蓝色荧光粉,采用X射线衍射、扫描电子显微镜和荧光光谱等手段,考察了不同助熔剂以及反应对BAM:Eu2晶体结晶度、物相纯度、粉体颗粒形貌和发光强度的影响,并对合成反应的机理进行了分析.结果表明,采用不同的助熔剂,均能制备出BAM:Eu2+发光材料,Eu2+的掺入对基质晶体结构没有明显的影响;相对不加助熔剂时,烧结温度大幅度降低,且制备的样品形貌更规整、颗粒大小更趋均一;随着烧结时间的延长,样品结晶更趋完整、杂相减少,粉体发光强度随之提高;随助熔剂用量的增加,粉体的发光性能得到改善,但助熔剂用量过量时,粉体结块、团聚,粉体的发光性能变差;采用不同的助熔剂,合成反应的机理发生变化,所得样品的结晶完整性、杂相组成和含量、发光中心的分布、粉体料径等性能产生相应变化,最终导致样品的发光性能发生改变,样品的特征发射峰强度随AlF3、H3BO3、MgF2、Li2CO3、无助熔剂依次降低.     

(Eu_xM_(1-x))Al_5O_(12)(M=Y,Gd)的发光性质研究

采用高温固相反应法合成(EuxY1-x)3Al5O12(x=0.001,0.005,0.01,0.05,0.1,0.2,0.5)、(Eu0.15GdyY0.85-y)3Al5O12(y=0.085,0.255,0.425,0.595,0.765)红色系列粉末状发光材料。经x射线衍射分析产物为单相,属立方晶系。测量了材料的激发光谱和发射光谱。发现(EuxY1-x)3Al5O12的激发光谱呈两个带状峰,峰值分别在240nm和395nm附近。随着Eu3+含量x由0.001增加到0.5,(EuxY1-x)3Al5O12发光强度先增加后减小,呈现明显的浓度猝灭现象。改变钆的含量,荧光粉的激发光谱和发射光谱线形不变,但强度发生变化。随着钆含量的增大,峰强度呈现先增大后减小的现象。H3BO3作助熔剂时粉末的发光整体高于NH4NO3作助熔剂时的发光强度,且发光亮度随助熔剂浓度的增加先增大后减小。     

Combustion synthesis and luminescence properties of blue NaBaPO4:Eu2+ phosphor

The blue-emitting phosphor NaBaPO4:Eu2+ was prepared by the combustion method. The phase structure and microstructure of the as-prepared samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Under the excita-tion wavelength of 360 nm, the emission spectrum exhibited only one blue band centering at 435 nm, which was ascribed to the 4f65d1→4f7 transition on Eu2+ ions. Compared with the phosphor obtained by solid-state reaction method, the relative emission intensity of sample ob-tained by combustion method increased slightly. The decay times and the temperature dependence luminescence intensities (25-300 oC) were discussed in order to further investigate the potential applications. Furthermore, Eu2+-doped NaBaPO4 phosphor showed higher thermally sta-ble luminescence comparable to commercially available Y3Al5O12:Ce3+ (YAG:Ce3+) phosphor. All the investigated suggestions that Na-BaPO4:Eu2+ is a good phosphor candidate applied in white light emitting diode.     

Flux and concentration effect on Eu^3＋ doped Gd2（MoO4）3 phosphor

A novel red emitting phosphor Gd2（MoO4）3：Eu^3＋ was prepared by solid reaction, using Gd2O3, Eu2O3 and WO3 as starting matedals and NH4F as flux. The effects of flux content and Eu^3＋ concentration on the crystal structure, morphology and luminescent properties were investigated using XRD, SEM and fluorescent spectrum measurement. The XRD patterns showed that the resultants had the monoclinic structure. With the increase in flux amount, their crystallization significantly improved. The SEM images indicated that the mean size of the phosphor particles was around 2 μm, and agglomeration of the phosphor particles appeared while introducing higher flux amount. The excitation spectra exhibited more intense f-f transitions originating from ground state 7^F0 to upper states 5^L6 and 5^D2 than the charge transfer band. The concentration quenching of Eu^3＋ emission indicated that energy transfer from Eu^3＋ to molybdate host existed even at lower Eu^3＋ concentration.     

Preparation of Stable CaS∶Eu~(2+), Tm~(3+) Phosphor

Alkalineearthsulfides (AES)havebeenfoundtobeexcellentandversatilephosphor ,andrareearthsasactivatorshavebeenintensivelyinvestigated[1～ 7] .Theyholdpromiseforapplicationsinphoto ,electro ,cathoderay ,fieldemissiondisplaysandluminescencepaints[8,9] .However ,alkalineearthsulfidesasaphos phorhosthavebeenfoundtobelimitedinapplica tion ,duemainlytoitssensitivetomoistureandotheratmosphericcomponents .Theirchemicalstabilityagainstatmosphericcarbondioxideandmoisturecouldbeenhancedthroughthegoodcryst…     

Luminescent properties of Eu³⁺-doped BaZrO₃ phosphor for UV white light emitting diode

A novel orange phosphor Eu3+ doped barium zirconate(BaZrO3) was synthesized by conventional solid state reaction method and its crystal structure and luminescent properties were investigated in this paper.The X-ray diffraction patterns(XRD) showed that simple BaZrO3 phase was obtained.Monitoring at 596 nm,the excitation spectrum consisted of a broad band and a series of narrow bands and the stronger excitation peaks located at 275 and 393 nm,respectively.The emission spectrum excited by 393 nm UV light was composed of four narrow bands.The strongest emission was located at 596 nm.The appropriate concentration of Eu3+ was 0.025(molar fraction) for the highest emission intensity at 596 nm.The H3BO3 and ammonium were added as flux and the results showed that 2 wt.% NH4F ions was the optimal flux for BaZrO3:Eu3+.     

复合熔盐法合成Y2O3.Eu3+红色荧光粉

以草酸钇铕(Y2(C2O4)3:Eu3+)为前驱体,采用复合熔盐(NaCl+S+Na2CO3)协助焙烧法合成Y2O3:E.u3+红色荧光粉.利用XRD、SEM、光谱分析等测试和分析荧光粉粒径、颗粒形貌以及发光性能.主要考察复合熔盐配比、用量以及焙烧温度和时间对Y2O3:Eu3+荧光粉发光性能的影响.结果表明,NaCl在...     

Eu3+激活的Li2Gd4（MoO4）7钼酸盐红色荧光体及其发光性质

由高温固相反应首次合成Li2(Gd1-xEux)4(MoO4)7(0相似文献   

Luminescent properties of Ba3Gd（BO3）3：Eu^3＋ phosphor for white LED applications

Luminescent material Ba3Gd(BO3)3 doped with Eu3+ ion was prepared by high temperature solid-state method. The preparing conditions, luminescent properties, and particle morphology of Ba3Gd(BO3)3:Eu3 + phosphor were studied with X-ray diffraction (XRD), fluorescence spectroscopy, and scanning electron microscopy (SEM). The results obtained by XRD showed that pure phase of Ba3Gd(BO3)3 was obtained at 1000℃. Images from SEM displayed that the particles of Ba3Gd(BO3)3:Eu3+ phosphor had a spherical shape with an average diameter of about 200-400 nm. The luminescence spectra showed that Ba3Gd(BO3)3:Eu3+ phosphor was effectively excited by the near ultraviolet (UV) light (396 nm) and blue light (466 nm). The main emission peaks of Ba3Gd(BO3)3:Eu3+ phosphor were assigned to the supersensitive transition 5D0-7F2 (611 and 616 nm) of Eu3+ ion when samples were excited at 255 and 396 nm, respectively, and the luminescent intensity of Ba3Gd(BO3)3:Eu3+ at 611 and 616 nm reached to the maximum when the doped content of Eu3+ ion was 10mol.%. Therefore, this phosphor could be a promising red component for possible applications in the field of white LED.     

Effect of gadolinium incorporation on optical characteristics of YNbO_4：Eu~（3＋） phosphors for lamp applications

Eu3+-doped (Y,Gd)NbO4 phosphor was synthesized by solid-state reaction for possible application in cold cathode fluorescent lamps. A broad absorption band with peak maximum at 272 nm was observed which was due to the charge transfer between Eu3+ ions and neighboring oxygen anions. A deep red emission at the peak wavelength of 612 nm was observed which could be attributed to the 5D0→7F2 transition in Eu3+ ions. The highest luminance for Y1-x-yGdyNbO4:Eux3+ under 254 nm excitation was achieved at Eu3+ concentration of 18 mol.% (x=0.18) and Gd3+ concentration of 8.2 mol.% (y=0.082). The luminance of Y0.738Gd0.082NbO4:Eu3+0.18 was higher than that of a typical commercial phosphor Y2O3:Eu3+ and the CIE chromaticity coordinate was (0.6490, 0.3506), which was deeper than that of Y2O3:Eu3+. The particle size of the synthesized phosphors was controlled by the NaCl flux and particle size as high as 8 μm with uniform size distribution of particles was obtained.     

Fabrication and luminescent properties of red phosphor M3BO6:Eu3+（M=La,Y）

A series of red phosphors M3BO6:Eu3+(M=La,Y) were synthesized at 1150 oC by conventional solid state reaction method and their luminescent properties were investigated.Structural characterization of the luminescent materials was carried out with X-ray powder diffraction(XRD) analysis.Photoluminescence measurements indicated that the La3BO6:Eu3+ phosphor exhibited bright red emission centered at about 612 nm 626 nm under UV excited.La3BO6:Eu3+ phosphor had better luminescent intensity than Y3BO6:Eu3+ phosphors under the same excitation and measuring conditions.It was shown that the 0.08 mol.% Eu3+ ions in La3BO6:Eu3+ phosphors was optimal.The color parameter indicated that La3BO6:Eu3+ phosphor was a preferable red phosphor for white LED.