Tb^(3+)、Eu^(3+)离子共掺杂的MgAl_(2)O_(4)发光性能研究

采用水热辅助固相法,以Al(NO_(3))_(3)·9H_(2)O和Mg(NO_(3))_(2)·6H_(2)O为原料,尿素为沉淀剂,制备了Tb^(3+)、Eu^(3+)共掺杂镁铝尖晶石荧光粉。用X射线衍射、扫描电子显微镜对所得产物的相结构和形貌予以表征,结合荧光激发、发射光谱和CIE色度图分析了荧光粉的光致发光性能。结果表明:在一定浓度范围内,掺杂Tb3+和Eu^(3+)离子后基质MgAl_(2)O_(4)的晶体结构并未发生改变,而当引入沉淀剂后,获得了具有良好分散性的棒状颗粒,且Tb^(3+)与Eu^(3+)间的浓度变化对样品形貌的影响甚微。在此基础上,以377 nm近紫外光作为激发光源实现了可见光区由粉至红的多色可调谐发射。

新型红色荧光粉Sr_(3)CaNb_(2)O_(9):Sm^(3+),Eu^(3+)的发光特性和能量传递分析

利用高温固相反应法制备一系列单基质荧光粉Sr_(3)CaNb_(2)O_(9):xSm^(3+),yEu^(3+)(x=0.04~0.09,y=0.03~0.15),并对样品的物相形貌、发光性能、能量传递机制和CIE色坐标进行分析。研究表明,Sr_(3)CaNb_(2)O_(9):xSm^(3+)荧光粉在激发波长为407 nm时的浓度淬灭点为x=0.07。在Sr_(3)CaNb_(2)O_(9):0.07Sm^(3+),yEu^(3+)荧光粉中,随着Eu^(3+)掺杂浓度的增加,Sm^(3+)的发光强度降低而Eu^(3+)发光强度却先增加后降低,Eu^(3+)的浓度淬灭点为y=0.09。Sm^(3+)→Eu^(3+)的能量传递以电偶极-电偶极相互作用为主,能量传递效率达到76.6%。色坐标图表明Eu^(3+)离子的加入可使色坐标从橙红色区域向纯红色区域移动。此外,样品还具有较高的色纯度和较低的色温。结果表明,Sr_(3)CaNb_(2)O_(9)∶Sm^(3+),Eu^(3+)荧光粉有望成为白光LED发出红光物质的候选材料。

具有持续反应活性的g-C_(3)N_(4)/Sr_(2)MgSi_(2)O_(7):Eu^(2+),Dy^(3+)复合材料的光学-催化行为研究

为促进环境友好型光催化技术的应用推广,通过热解聚合方式将g-C3N4负载于多孔Sr_(2)MgSi_(2)O_(7):Eu^(2+),Dy^(3+)蓝色长余辉荧光粉上,制备具有持续反应活性的g-C_(3)N_(4)/Sr_(2)MgSi_(2)O_(7):Eu^(2+),Dy^(3+)复合材料。首次采用累积污染物降解效率等一系列指标评价材料在光照及暗态下综合去除污染物效果。通过微观表征手段和NO去除试验研究了单组分复配质量比对复合材料的光学及催化性能的影响。结果表明,g-C_(3)N_(4)的复合对Sr_(2)MgSi_(2)O_(7):Eu^(2+),Dy^(3+)的荧光强度和余辉性能产生了不利影响;但光照下,提高的光生载流子分离效率和光吸收能力使复合材料的光催化活性增强;暗态下,内在光源Sr_(2)MgSi_(2)O^(7):Eu^(2+),Dy^(3+)的存在赋予了复合材料持续去除NO的能力,该能力的持续时间与余辉亮度、光催化活性有关。本研究有助于推动持续活性光催化体系的发展。

近紫外光LED芯片用红色荧光粉SrIn_2O_4:Eu^(3+),Sm^(3+)的制备及性能研究

利用高温固相法制备了Eu^(3+)、Sm^(3+)单掺杂及共掺杂的SrIn_2O_4荧光材料.通过XRD、激发光谱、发射光谱等对SrIn_2O_4∶Eu^(3+)、Sr In_2O_4∶Sm^(3+)、Sr In2O4∶Eu^(3+),Sm^(3+)进行表征。结果表明,Sr In2O4∶Eu^(3+)在近紫外光395 nm激发下能够有效的产生616 nm的红光发射.在Sr In2O4∶Sm^(3+)体系中发现,该系列样品适合于407 nm的紫光激发,发射峰位于607 nm.在Sr In_2O_4∶Eu3^(3+)Sm^(3+)体系中,通过光谱分析发现,基质中存在Eu^(3+)和Sm^(3+)激活剂之间的相互能量传递过程.该能量传递过程使Sr In2O4∶Eu^(3+),Sm^(3+)更适合于390~410 nm紫外芯片激发的LED用红色荧光粉。

Eu^(3+)掺杂Ca_(2)ZrSi_(4)O_(12)的红色荧光粉性能分析

采用高温固相法制备Ca_(2(1-x))ZrSi_(4)O_(12):2x Eu^(3+)系列红色荧光粉,并对样品的物相结构、荧光特性、热稳定性和色坐标进行实验分析。分析结果表明:红色荧光粉Ca_(2)ZrSi_(4)O_(12):Eu^(3+)可以被紫外光或蓝光激发,并在612 nm处表现出较强的红光发射;Eu^(3+)的最佳掺杂浓度为60%,浓度淬灭机理归因于电四级-电四极相互作用;样品在室温到453 K这一温度范围内有较为良好的热稳定性;所有样品色坐标均位于红色发光区域。表明Eu^(3+)掺杂Ca_(2)ZrSi_(4)O_(12)荧光粉在白光LED领域具有潜在的应用前景。

溶胶-凝胶法合成SrAl_(2)O_(4):Eu^(2+),Dy^(3+)发光材料及其影响因素

SrAl_(2)O_(4):Eu^(2+),Dy^(3+)是商用的绿光长余辉发光材料,在许多领域具有实际的应用。本文采用溶胶-凝胶法制备SrAl_(2)O_(4):Eu^(2+),Dy^(3+)材料,通过控制变量法指导学生分析铝/锶投料比、铝/尿素投料比和煅烧气氛等几个关键因素对SrAl_(2)O_(4):Eu^(2+),Dy^(3+)的发光性质和氧化还原性质的影响。SrAl_(2)O_(4):Eu^(2+),Dy^(3+)材料的溶胶-凝胶法的最佳合成条件是化工生产的重要参数,本教学工作有助于培养学生的科学研究的思路和实验操作能力,研究工作也为优化SrAl_(2)O_(4):Eu^(2+),Dy^(3+)材料的品质和发光性能提供重要的参考意义。

Improving luminescent property of SrIn_2 O_4 :Eu^(3+) by co-doped A^+ (A = Li, Na, K) or Sm^(3+)

A series of SrIn2 O4 ：Eu^3＋ phosphors are synthesized by a high temperature solid-state method, and their luminescent properties are investigated. They can be excited by 395-nm radiation, and produce red emission （619 nm）; however, they have a low absorption of near-ultraviolet light with the wavelength of 400nm–405 nm. When co-doped with A^＋ （A=Li, Na, K）, the emission intensity of SrIn2O4 ：Eu^3＋ is significantly enhanced, but its emission and excitation spectral profile is unchanged. With co-doping Sm^3＋ , not only is the emission intensity of SrIn2 O4 ：Eu^3＋ enhanced, but also the absorption is broadened and strengthened in the range of 400 nm–405nm. The effect of Sm^3＋ -doped content on the emission intensity of SrIn2O4 ：Eu^3＋ , Sm^3＋ is investigated, and the optimal Sm^3＋ content is 0.02 mol.

沉淀-燃烧法合成SrAl_2O_4:Eu^(2+),Dy^(3+)长余辉材料

通过沉淀-燃烧法合成了SrAl_2O_4:Eu^(2+),Dy^(3+)长余辉材料,对合成样品进行了物相、形貌、发光特性研究,探讨了尿素用量对材料发光性能的影响。结果表明,当尿素用量为原料中金属硝酸盐总物质的量的6倍时,产物主晶相为单斜晶系的SrAl_2O_4;激发、发射光谱均为宽带谱,峰值分别位于368nm、518nm处;测得初始发光亮度为18700mcd/m^2,在暗室中放置9天后,仍可观察到明显发光现象。

SiO_(2)包覆对SrAl_(2)O_(4):Eu^(2+),Dy^(3+)及其复合涂层发光性能影响

以正硅酸乙酯(TEOS)为前驱体,采用溶胶-凝胶法制得SiO_(2)-SrAl_(2)O_(4)包覆粉体,利用超音速等离子喷涂技术在45#钢基体上制备了Cu-14Al-X/SrAl_(2)O_(4)(未包覆/包覆)复合涂层。采用扫描电子显微镜、X射线衍射仪和激光粒度分析仪对SrAl_(2)O_(4):Eu^(2+),Dy^(3+)磷光粉和SiO_(2)-SrAl_(2)O_(4)包覆粉体进行表征。利用荧光分光光度计对包覆前后磷光粉及Cu-14Al-X/SrAl_(2)O_(4)(未包覆/包覆)复合涂层的发光性能进行分析,探究超音速等离子喷涂过程中SiO_(2)表面包覆防猝灭工艺效果。结果表明:SiO_(2)包覆膜层未改变SrAl_(2)O_(4):Eu^(2+),Dy^(3+)磷光粉的晶体结构,对磷光粉的发光性能影响不大,可起到有效的隔离和保护作用,使磷光粉的发光性能得到改善,防猝灭效果较好。

MgAl_(2)O_(4):Eu^(3+)荧光粉的制备及其光谱特性

采用水热辅助固相法合成一系列Eu^(3+)掺杂MgAl_(2)O_(4):Eu^(3+)荧光粉。主要考察粉体的物相结构、形貌、颗粒尺寸及电/磁偶极跃迁强度随Eu^(3+)摩尔分数的变化规律。结果表明:当Eu^(3+)不等价取代Mg^(2+)后并未影响基质材料的晶体结构,产物全部为立方相MgAl_(2)O_(4),但间隙O^(2−)的存在会影响被取代离子Mg^(2+)的配位关。当Eu^(3+)掺入时,其会与溶液中的NH_(4)^(+)共同参与调控样品的形貌和尺寸,以致片状颗粒的厚度减小、不规则程度加剧。基于J-O理论认为,在248 nm紫外和395 nm近紫外光激发下,Eu^(3+)在MgAl_(2)O_(4)中所处格位的对称性差异是引起电偶极(^(5)D_(0)→^(7)F_(2))和磁偶极(^(5)D_(0)→^(7)F_(1))跃迁相对强度不同的主要原因。

低热猝灭新型Sr_(3)Ga_(2)Ge_(4)O_(14)∶Sm^(3+)橙红色荧光粉

采用高温固相法制备一系列新型Sr_(3-x)Ga_(2)Ge_(4)O_(14)∶xSm^(3+)(x=0~0.20)及Sr_(2.88)Ga_(2)Ge_(4)O_(14)∶0.06Sm^(3+),0.06M(M=Li^(+),Na^(+),K^(+))荧光粉,通过物相形貌、荧光光谱、热稳定性及CIE色度坐标等分析手段对样品性能进行了详细研究。根据不同掺杂浓度Sr_(3-x)Ga_(2)Ge_(4)O_(14)∶xSm^(3+)的荧光发射谱,发现Sm^(3+)最佳掺杂浓度为x=0.06,其荧光浓度猝灭归因于Sm^(3+)之间的电偶极-电偶极相互作用。研究发现,通过共掺杂M(M=Li^(+),Na^(+),K^(+))做电荷补偿离子可以提升Sr_(3-x)Ga_(2)Ge_(4)O_(14)∶xSm^(3+)的发光性能。此外,随着Sm^(3+)掺杂浓度提高,其荧光寿命不断减小。最后探讨了Sr_(3-x)Ga_(2)Ge_(4)O_(14)∶xSm^(3+)的CIE色度坐标和热稳定性,其CIE色度坐标位于橙红光区域,且在423 K的发光强度大概为其室温的95%。研究表明,Sr_(3-x)Ga_(2)Ge_(4)O_(14)∶xSm^(3+)作为新型橙红荧光粉有望应用于白光发光二极管(WLED)。

PET夜光纤维中SrAl_(2)O_(4)∶Eu^(2+),Dy^(3+)的回收及发光性能研究

为探究SrAl_(2)O_(4)∶Eu^(2+),Dy^(3+)稀土发光材料循环再生利用的可行性,以废弃夜光聚酯(PET)长丝作为原材料,采用乙二醇醇解法降解夜光PET长丝。回收夜光纤维中的发光材料SrAl_(2)O_(4)∶Eu^(2+),Dy^(3+)。并通过改变催化剂(乙酸锌)的用量,探究催化剂含量对回收夜光纤维中发光材料性能的影响。利用扫描电镜、X射线衍射仪、荧光余辉亮度测试仪和荧光光谱仪对夜光纤维中回收得到的发光材料的表面形貌和发光性能进行分析与表征。结果表明:发光材料的X射线衍射峰与PDF卡片基本一致,纺丝和降解过程不影响发光材料的光色特性和余晖衰减规律;当催化剂添加质量为0.5%时,回收得到的夜光粉纯度为91.67%,初始余晖亮度达到4.0891cd/m^(2)。

白光LED用Ba_(6)Gd_(2)Ti_(4)O_(17):Sm^(3+)红色荧光粉的制备及发光性能研究

采用传统的高温固相法制备一种新型的红色荧光粉Ba_(6)Gd_(2)Ti_(4)O_(17):Sm^(3+),并通过X射线衍射(X-ray diffraction,XRD)、扫描电子显微镜(scanning electron microscope,SEM)、荧光(photoluminescence,PL)光谱及色坐标表征系列样品的物相、形貌和发光性能.PL光谱表明该荧光粉可以被近紫外光有效激发,在407 nm近紫外光激发下,发射光谱由四个发射峰组成,最强发射峰位于616 nm处,归结为Sm^(3+)的^(4)G_(5/2)→^(6)H_(7/2)跃迁.随着Sm^(3+)掺杂量的增加,荧光粉的发光强度先增大后减小,最佳掺杂比例(物质的量分数)为3%.系列掺杂比例荧光粉的色坐标基本不变,均位于红光区.研究结果表明,该荧光粉是一种具有应用前景的新型白光发光二极管(light-emitting diode,LED)用红色荧光粉.

Magnetic and luminescent properties of bifunctional composite Fe_(3)O_(4)@Y_(2)O_(2)S:Eu^(3+)

As a kind of non-destructive testing method,magnetic particle inspection is widely used in the fields of aviation and high-speed rail.The properties of magnetic fluorescent bifunctional composites,such as fluorescence intensity and magnetic properties,have increasing demands in magnetic particle inspection.Rare earth compounds offer potential as novel materials for fluorescent magnetic bifunctional composites due to their excellent optical properties and extremely narrow emission spectra.In this work,the rare earth fluorescent material Y_(2)O_(2)S:Eu^(3+) was synthesized by solid-state reaction method.Fe_(3)O_(4)nanoparticles prepared by hydrothermal method were uniformly coated on the Y_(2)O_(2)S:Eu^(3+) particles through physical adsorption of surfactants.The obtained Fe_(3)O_(4)@Y_(2)O_(2)S:Eu^(3+) exhibits dark red color under the ultraviolet light.In additio n,X-ray diffractio n,morphology,photoluminescence and hyste resis loop of Fe_(3)O_(4)@Y_(2)O_(2)S:Cu^(3+) were investigated.The luminescence mechanism of Y_(2)O_(2)S:Eu^(3+) is described in detail Fe_(3)O_(4)@Y_(2)O_(2)S:Cu^(3+) displays good paramagnetism and has a good controllability under a magnetic field.The magnetic particle inspection of Fe_(3)O_(4)@Y_(2)O_(2)S:Eu^(3+) was performed using a 4-pole electromagnet and a test piece shim.The magnetic fluorescent bifunctional composite presented in this work can be applied for non-destructive testing.

Quenching Study on Iron Impurity in Eu^(2+), Dy^(3+) Doped Strontium Aluminate Phosphor Prepared by Nano-Coating Process

A series of long afterglow phosphors, Eu2+, Dy3+, with different iron content were prepared by nano-coating process. The resulted precursors were characterized by Transmission Electron Microscope (TEM), which suggested that the precursor particles had nanometer size distribution. The optical quenching of iron impurity on the phosphor powders were investigated by X-Ray powder Diffraction (XRD) and photoluminescence methods. The XRD indicates that a pure monoclinic SrAl2O4∶Eu2+, Dy3+ was formed at 1200 ℃ and iron impurity up to 296.36×10-4% had no effect on the SrAl2O4∶Eu2+, Dy3+ phase structure. However, the luminescence intensity were strongly dependent on the trace iron impurity, which might be explained that iron displace the aluminium and form Fe-O bond, which competed energy with Eu2+ and transfer red them to infrared sites.

新型橙红色荧光粉Sr_(4)Nb_(2)O_(9):Sm^(3+)的光致发光性能研究

采用高温固相法制备了一系列新型Sr_(4-x)Nb_(2)O_(9):xSm^(3+)橙红色荧光粉,对Sr_(4-x)Nb_(2)O_(9):xSm^(3+)的物相结构、光致发光性能、荧光衰减、热稳定性等进行了研究。结果表明,Sr_(4-x)Nb_(2)O_(9):xSm^(3+)橙红色荧光粉能被近紫外和蓝光有效激发,并在607 nm处呈现出较强的橙红光发射带。研究了样品的浓度猝灭机制,样品的最佳掺杂浓度为0.02,其浓度猝灭归因于Sm^(3+)离子间的电偶极间相互作用。此外,还探讨了Sr_(3.98)Nb_(2)O_(9):0.02Sm^(3+)样品的热稳定性,在453 K时的发光强度大约为室温下的89.6%。最后对样品的荧光寿命和CIE进行了测试,随着Sm^(3+)掺杂浓度提高,荧光寿命不断变短;所有样品的相关色温较低,具有较高的色纯度。上述结果表明,Sm^(3+)掺杂Sr_(4)Nb_(2)O_(9)的橙红色荧光粉在固态照明领域中具有潜在的应用前景。

Photoluminescence properties and energy transfer of novel orange–red emitting phosphors:Ba_(3)Bi_(2)(PO_(4))_(4):Sm^(3+),Eu^(3+) for white light-emitting diodes

Sm^(3+), Eu^(3+)co-coped Ba_(3)Bi_(2)(PO_(4))_(4) phosphors,as potential phosphors for white light-emitting diode applications, were synthesized through the solid-state reaction method for the first time. The crystal structure,absorption spectra, photoluminescence properties, decay time, energy transfer mechanism, temperature-dependent properties, and Commission International De L’Eclairage(CIE) chromaticity coordinates were investigated systematically. The pure eulytite-type Ba_(3)Bi_(2)(PO_(4))_(4) phase was obtained after heating at 980 ℃ for 5 h. A notably enhanced absorption efficiency at 393 nm was observed when Sm^(3+), as a sensitizer, was doped into Ba_(3)Bi_(1.82)(PO_(4))_(4): 0.18 Eu^(3+)and the band gap of the Ba_(3)Bi_(2)(PO_(4))_(4) host was estimated to be 4.19 eV. The emission intensity of Ba_(3)Bi_(1.82)(PO_(4))_(4): 0.18 Eu^(3+)was significantly enhanced when Sm^(3+)was co-doped. The existence and mechanism of energy transfer from Sm^(3+) to Eu^(3+)were evaluated by photoluminescence spectra and decay time measurements. The CIE chromaticity coordinate of Ba3 Bi1.75(PO4)4: 0.07 Sm^(3+), 0.18 Eu^(3+) phosphor was calculated to be(0.5746, 0.4197), respectively.

Y_(2)O_(2)SO_(4):Eu^(3+)亚微米棒的合成及发光性能

以Na_(2)SO_(4)和K_(2)SO_(4)为熔盐,采用熔盐法合成了一维Y_(2)O_(2)SO_(4):Eu^(3+)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、Eu^(3+)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Y_(2)O_(2)SO_(4):Eu^(3+)亚微米棒,Y_(2)O_(2)SO_(4):Eu^(3+)亚微米棒的长度大于10μm,宽度为500~800 nm。在270 nm紫外光的激发下,Y_(2)O_(2)SO_(4):Eu^(3+)亚微米棒呈红光发射,最强发射峰位于616 nm处,归属于Eu^(3+)的^(5)D_(0)→^(7)F_(2)跃迁,Y_(2)O_(2)SO_(4):Eu^(3+)亚微米棒Eu^(3+)的最佳掺杂浓度为10mol%。

微波辐射法合成Gd_(2)O_(2)SO_(4)∶Eu^(3+)发光材料及性能研究

以Gd_(2)O_(3)、Eu_(2)O_(3)和NH_(4)HSO_(4)为原料,采用微波辐射法合成了Gd_(2)O_(2)SO_(4)∶Eu^(3+)发光材料。并用X射线衍射仪、扫描电镜、荧光光谱仪对所得发光材料的物相、形貌和发光性能进行了表征。结果表明,微波辐射30 min可以合成纯相Gd_(2)O_(2)SO_(4)∶Eu^(3+)发光材料,晶体结构为正交晶系,与Gd_(2)O_(2)SO_(4)结构相同;其形貌不规则,存在团聚现象;Gd_(2)O_(2)SO_(4)∶Eu^(3+)发光材料呈红光发射,发射光谱由一系列铕离子的^(5)D_(0)→^(7)F_(j)(j=0,1,2,3,4)能级跃迁的尖峰组成,激发光谱主要由处于200 nm~350 nm的宽激发带和位于397 nm和466 nm的窄激发带组成。

Optical performance study of Sr_2ZnSi_2O_7:Eu^(2+),Dy^(3+), SrAl_2O_4:Eu^(2+),Dy^(3+) and Y_2O_2S:Eu^(3+),Mg^(2+),Ti^(4+) ternary luminous fiber

In this study, down-conversion fluorescent powder of Sr2ZnSi2O7：Eu-（2＋）,Dy-（3＋）, SrAl2O4：Eu-（2＋）,Dy-（3＋） and Y2O2S：Eu-（3＋）,Mg-（2＋）,Ti-（4＋）, which were the common three primary colors materials with long afterglow, were synthesized by high temperature solid state method. The blends of rare earth（RE） luminescent materials have been of interest to reinvest the luminescent characteristics of polyethylene terephtahalate（PET） luminous fiber. The scanning electron microscopy（SEM） and an inversion fluorescence microscope were used to characterize the surface morphology and the dispersion of inclusion. Through analysis of microcosmic morphology, three typical dispersions of luminescent particles were summarized. The X-ray diffraction indicated that the phase structure of fiber samples and crystal structure of luminescence materials kept complete after prilling and spinning. From the fluorescence spectra and CIE 1931 coordinates, it could be found that different combinations of luminous fibers were desired to obtain divers colors emission luminous fiber. And the fiber samples were a light sensation which could induct different excitation wavelengths and convert it down to different colors. The afterglow decay curve and its differential curve were summarized indicating the three decay stages. The decay curve and decay rate curve showed that the contents of Sr2ZnSi2O7：Eu-（2＋）,Dy-（3＋）, SrAl2O4：Eu-（2＋）,Dy-（3＋） and Y2O2S：Eu-（3＋）,Mg-（2＋）,Ti-（4＋） had obvious influence on the afterglow of fiber samples.