BaAl_2O_4:Eu直接白色荧光粉的制备及其发光性能

采用高温固相法,通过控制反应温度和Eu~(3+)掺杂量,制备Ba Al_2O_4:Eu直接白色荧光粉。以电荷补偿模型为基础讨论了自还原机理。当合成温度为1 200℃、Eu~(3+)掺杂量为12%(摩尔分数)时,荧光粉颜色趋近于白光,色坐标位于(0.36,0.38)。通过X射线光电子能谱、发射和激发光谱以及漫反射光谱,研究了Ba Al_2O_4:Eu荧光粉的发光性能。结果表明:荧光粉中存在2个发光中心,分别与Ba的2种格位相对应。Eu2+和Eu~(3+)共存于基质中,说明Eu~(3+)在空气中发生自还原反应。主峰位于500 nm处的发射宽谱符合Eu2+的4f 65d–4f 7跃迁,596、619、655以及709 nm处的发射峰分别对应Eu~(3+)的4f–4f中5d0–7fJ(J=1,2,3,4)特征发射跃迁,发射峰以619 nm处的5d0–7f2电偶极跃迁为主。     

Si~(4+)掺杂对橙红色荧光粉NaBaSi_xP_(1-x)O_4:Eu~(3+)结构和发光性能的影响

采用高温固相法合成了一系列NaBaSi_xP_(1-x)O_4:Eu~(3+)橙红色荧光粉。表征了荧光粉的晶体结构和发光性能。考察了煅烧温度和Si~(4+)掺杂量对荧光粉结构和发光性能的影响。结果表明:掺杂Si~(4+)对荧光粉的晶型没有明显影响,但是导致了晶格膨胀。750℃煅烧时基质已形成NaBaPO_4相,晶型为六方晶系,荧光粉发射峰强度最强。激发光谱由200~280 nm的宽带和310~500 nm的一系列尖峰组成,分别对应于O~(2–)→Eu~(3+)电荷迁移带和Eu~(3+)的f→f能级跃迁吸收,最强激发峰位于393 nm左右,与近紫外LED芯片的发射光谱匹配。在393 nm近紫外光激发下,最强发射峰和次强发射峰分别位于红光616 nm和橙光591 nm附近,分别属于Eu~(3+)的~5D_0→~7F_2和~5D_0→~7F_1特征跃迁。NaBa_(0.92)Si_xP_(1–x)O_4:0.08Eu~(3+)中Si~(4+)的最佳掺杂量为0.02 mol,Na Ba_(0.92)Si_(0.02)P_(0.98)O_4:0.08Eu~(3+)样品在616和591 nm附近的发射强度比单掺杂Eu~(3+)的样品分别提高了66.6%和63.6%。     

橙红色荧光粉NaBa1-xPO4:xEu3+中Eu3+的占位情况及光谱性质

采用高温固相法合成了NaBa_(1-x)PO_4:xEu~(3+)系列橙红色荧光粉。用X射线衍射、扫描电子显微镜、荧光光谱以及色坐标等手段对荧光粉的晶体结构和发光性能进行表征;考察了Eu~(3+)的掺杂摩尔量对荧光粉的晶体结构和发光性能的影响。结果表明:Eu~(3+)的掺杂并没有改变荧光粉的晶体类型,但是导致了晶格收缩,其基质主相是六方晶系的NaBaPO_4。在393 nm近紫外光激发下,最强发射峰和次强发射峰分别位于红光616 nm和橙光591 nm附近,分别属于Eu~(3+)的~5D_0→~7F_2和~5D_0→~7F_1特征跃迁。Eu~(3+)的掺杂量为0.20 mol时荧光粉的发射峰强度最大。Eu~(3+)的光谱性质及其占据基质晶格中Ba(Ⅱ)和Ba(Ⅰ)位点的比例随Eu~(3+)掺杂量的变化而变化,改变Eu~(3+)的掺杂量可以有效调节荧光粉发射光谱中的红、橙光比例。其中荧光粉NaBa_(0.80)PO_4:0.20Eu~(3+)的性能优异,适合与近紫外LED芯片相匹配发光。     

黄色荧光粉Sr8ZnLu(PO4)7:Eu2+,Mn2+的制备与发光性能研究

采用高温固相法制备新型黄色荧光粉Sr_8ZnLu(PO_4)_7:Eu~(2+), Mn~(2+)。分别通过X射线衍射,扫描电镜和荧光光谱研究了材料的物相结构,形貌和发光性能。单掺Eu~(2+)样品在250～450 nm范围内出现宽峰吸收,预示着该材料可被近紫外芯片有效激发。Eu~(2+)发射光谱峰值位于520 nm,发光猝灭的机理被确定为偶极-偶极相互作用。在Eu~(2+)-Mn~(2+)共掺样品中荧光粉展现400～700 nm范围可调的宽峰发射。研究表明Sr_8ZnLu(PO_4)_7:Eu~(2+), Mn~(2+)黄色荧光粉在近紫外芯片激活的白光LED领域有潜在应用。     

高效红色荧光粉Li1–xAlSiO4+x:xEu3+的制备与发光性能

以碳酸锂、氧化铝、二氧化硅、Eu_2O_3为原料,采用传统高温固相法在1150℃制备系列Eu~(3+)掺杂LiAlSiO_4红色荧光粉Li_(1–x)AlSiO_(4+x):xEu~(3+)(x=0.05～0.18)。利用XRD、SEM和光致发光光谱分别对其晶体结构,粉体形貌和发光性能进行了表征。考察了Eu~(3+)掺杂量对所制红色荧光粉发光强度、色温、色调的影响。结果表明:Eu~(3+)掺杂摩尔分数低于15.0%时,样品为单一基质;样品可以被近紫外350～420 nm波段高效激发,最强激发发射峰位于394 nm。发射光谱呈现出Eu~(3+)的特征峰,谱带峰值在593、616 nm处,分别对应于Eu~(3+)的~5D_0→~7F_1、~5D_0→~7F_2特征跃迁。最强发射对应Eu~(3+)掺杂摩尔分数为12.0%,浓度猝灭主要是因为四极-四极(q-q)相互作用,CIE坐标为(0.6464,0.3526),可应用于近紫外芯片激发LED用红色荧光粉。     

白光LED用Na_(0.45)La_(3.16)W_5O_(20):Eu~(3+)红色荧光粉的发光性质研究

采用共沉淀法制备了Eu~(3+)掺杂Na_(0.45)La_(3.16)W_5O_(20)红色荧光粉,利用XRD、荧光光谱等方法对荧光粉的组成结构及发光性能进行了表征。结果表明,Na_(0.45)La_(3.16)W_5O_(20):Eu~(3+)荧光粉在612nm波长光监测下的激发光谱是由一宽带和系列锐峰组成,其最强激发峰位于蓝光465nm处,这与目前被广泛使用的蓝光LED芯片的输出波长以及商业化生产的460nm光源相匹配。该荧光粉可以被465nm蓝光有效激发,得到614nm处Eu~(3+)非常强的5D0→7F2电偶极跃迁发射峰,是一种能够较好应用在近紫外激发的白光LED用红色荧光粉材料。     

发光增强的红色荧光粉Li6Zr2O7:Eu3+的微波固相合成

以硝酸锆、硝酸锂、Eu(NO_3)_3·6H_2O为原料,采用微波固相烧结法合成了系列红色荧光粉Li_6Zr_2O_7:Eu~(3+)。利用XRD和荧光光度计对样品的组成和发光性能进行了表征。考察了烧结时间、烧结温度及Eu~(3+)的含量对荧光粉发光性能的影响。XRD分析结果表明,Li_6Zr_2O_7:Eu~(3+)荧光粉为纯相晶体结构。根据离子电负性标度可知,Eu~(3+)(1.433)会优先取代电负性相近Zr~(4+)的位置(1.610)。当微波烧结时间为10 min、烧结温度为500℃、Eu~(3+)在晶体中的含量为14%时(以Li_6Zr_2O_7的物质的量为基准,下同),在465 nm激发下,制备得到的Li_6Zr_2O_7:0.14Eu~(3+)荧光粉在615 nm处产生最强的红光发射,且发射光谱在615 nm的强度是激发光谱在465 nm强度的1.54倍。此时荧光粉色坐标为X=0.65,Y=0.35,具有很高的色纯度,与商用红色荧光粉(0.63,0.34)相比更接近国家标准(0.67,0.33)。     

近紫外光激发的颜色可调Sr_2SiO_4:Gd~(3+),Tb~(3+),Eu~(3+)荧光粉的制备及其发光性能研究

采用液相沉淀法制备了近紫外光激发的颜色可调Sr_2SiO_4:0.06Gd~(3+),0.06Tb~(3+)、Sr_2SiO_4:0.06Gd~(3+),0.06Eu~(3+)和Sr_2SiO_4:0.06Gd~(3+),0.03Tb~(3+),0.03Eu~(3+)荧光粉,利用XRD、SEM、荧光光谱以及色坐标分析研究了所制备荧光粉的结构、形貌和发光性能。XRD分析表明,Sr_2SiO_4:0.06Gd~(3+),0.06Tb~(3+)、Sr_2SiO_4:0.06Gd~(3+),0.06Eu~(3+)和Sr_2SiO_4:0.06Gd~(3+),0.03Tb~(3+),0.03Eu~(3+)荧光粉样品属单斜晶系。荧光光谱分析表明,Sr_2SiO_4:Gd~(3+),Tb~(3+),Eu~(3+)的激发光谱包括200~300nm的宽带吸收峰和Tb~(3+)、Eu~(3+)的系列吸收峰。在243nm、354nm紫外光激发下,Sr_2SiO_4:0.06Gd~(3+),0.06Tb~(3+)的发射光谱由Tb~(3+)的~5D_4→~7F6(490nm,蓝绿光)、~5D_4→~7F_5(548nm,绿光)和~5D_4→~7F4(588nm,黄光)跃迁发射峰组成。在243nm、364nm紫外光激发下,Sr_2SiO_4:0.06Gd~(3+),0.06Eu~(3+)的发射光谱由Eu~(3+)的~5D_0→~7F_1(591nm,橙光)、~5D_0→~7F2(614nm,红光)、~5D_0→~7F_3(652nm,红光)跃迁发射峰组成。在243nm、252nm、364nm紫外光激发下,Sr_2SiO_4:0.06Gd~(3+),0.03Tb~(3+),0.03Eu~(3+)的发射光谱由Tb~(3+)的~5D_4→~7F_6(490nm,蓝绿光)、~5D_4→~7F_5 (548nm,绿光)、~5D_4→~7F_4(588nm,黄光)和Eu~(3+)的~5D_0→~7F_1(591nm,橙光)、~5D_0→~7F_2(614nm,红光)、~5D_0→~7F_3(652nm,红光)跃迁发射峰组成。色坐标分析表明,Sr_2SiO_4:0.06Gd~(3+),0.03Tb~(3+),0.03Eu~(3+)是很好的近紫外光激发的三色发光荧光粉。     

Sm~(3+)、Ce~(3+)掺杂Y_2O_3:Eu~(3+)的低温燃烧法制备及发光性能

采用低温燃烧法分别制备了Y_2O_3:Eu~(3+)和钐(Sm~(3+))、铈(Ce~(3+))掺杂的Y_2O_3:Eu~(3+)红色荧光粉,并研究了反应温度及掺杂量对荧光粉性能的影响。使用激光粒度仪、X射线粉末衍射仪和荧光光谱仪,对样品的物相、粒度及发光特性进行了表征和分析。结果表明,Y_2O_3:Eu~(3+)的最佳反应温度为200℃,Sm~(3+)和Ce~(3+)掺杂Y_2O_3:Eu~(3+)的粒径分别分布在396～615 nm和531～955 nm,Sm~(3+)和Ce~(3+)的掺杂均能显著增强Y_2O_3:Eu~(3+)红色荧光粉的发光性能。     

Sr_6La_4(SiO_4)_2(PO_4)_4O_2:xEu~(2+),yMn~(2+)荧光粉的制备及性能

采用高温固相法制备Sr_6La_4(SiO_4)_2(PO_4)_4O_2:xEu~(2+),yMn~(2+)荧光粉。通过X射线粉末衍射和结构精修研究了其物相组成和晶体结构以及该荧光粉的激发光谱、发射光谱、漫反射光谱、荧光热稳定性等发光性能。结果表明:该荧光粉具有磷灰石结构,Eu~(2+)和Mn~(2+)可占据结构中的2种阳离子格位。当Eu~(2+)的掺杂量为1%(摩尔分数)、Mn~(2+)的掺杂量为2%时,此荧光粉发光性能最好;荧光粉的发射光谱为450～550 nm的宽发射带,峰值位于478 nm,其激发光谱为220～400 nm的宽激发带,峰值位于302 nm,其色坐标值为(0.203 5,0.307 8);Mn~(2+)的掺杂有效的促进了荧光粉对近紫外光区域的吸收。当温度提升至150℃,Sr_6La_4(SiO_4)_2(PO_4)_4O_2:0.01Eu~(2+)和Sr_6La_4(SiO_4)_2(PO_4)_4O_2:(0.01Eu~(2+),0.02Mn~(2+))荧光粉的发射光谱强度分别为室温的34.46%和51.79%;Mn~(2+)的掺杂显著提升了其热稳定性。     

白光LED用红色荧光粉Gd2-xMo3O9:Eux3+制备和研究

用高温固相法成功制备了Gd2-xMo3O9:Eux3+,用XRD荧光光谱仪对其物相以及粉体的激发和发射光谱进行表征和研究;结果表明:在395和464nm两主激发峰均可得到616nm处红光发射峰,属于Eu3+典型的5D0→7F2的跃迁所致。由464nm激发得到的发射峰为单峰,峰宽较窄且发射强度较强。     

Anomalous thermal quenching of Ca2-xGe7O16:xMn2+ orange-emitting phosphors

The anomalous thermal quenching of phosphors maintains good luminescence properties at higher temperatures, which is great significant in the application of phosphors. Here, Ca_2-xGe₇O₁₆:xMn²⁺ phosphor has been synthesized by a solid sintering method. The luminescence properties of Ca_2-xGe₇O₁₆:xMn²⁺ is studied systematically It produce a broad spectrum emission around 600 nm under 222-nm ultraviolet excitation, with a maximum emission intensity as the concentration x = 0.015. The fluorescence lifetime decreased from 9.4 to 8.0 ms, with Mn²⁺ increasing from 0.005 to 0.03. The most interesting phenomenon is that the emission increases first and then decreases with temperature growing up. The maximum emission is 113% at 100 °C of that at room temperatures. The intensity is 101% as the temperature is 150 °C. The excellent thermal stability is very useful in the application.     

Characterization of Ca2SiO4:Eu2+ Phosphors Synthesized by Polymeric Precursor Process

The green emitting Ca₂SiO₄:Eu²⁺ (C₂S:Eu) phosphors were synthesized by the polymeric precursor process (Pechini-type), and the effects of calcination temperature and europium (Eu) doping concentration on the luminescent properties were investigated. The crystalline β-C₂S was obtained in the calcination temperature of 1100°–1400°C, and Eu was reduced into Eu²⁺ by annealing in 5% H₂/N₂ atmosphere. The obtained C₂S:Eu²⁺ phosphors exhibited a strong emission at 504 nm under the excitation of λ_exc=350 nm. The highest photoluminescence (PL) intensity was observed in the C₂S:Eu²⁺ phosphors either calcined at 1300°C or doped with 3 mol% Eu. The obtained PL properties were discussed in terms of crystal structure, particle size and shape, surface roughness, and effect of concentration quenching.     

Synthesis and optical characterization of novel Sr3Ga2O6:Eu phosphor

Alkaline earth metal gallets have been identified as an important ceramic material. The crystal chemistry of many of these gallets is well explored; however, very rare studies regarding optical properties of rare earth (RE) ions doped in such gallets, particularly in Sr₃Ga₂O₆ host, have been carried out. The present study reports on synthesis and characterization of novel Sr₃Ga₂O₆:Eu³⁺ phosphors. The phosphors have been synthesized using a conventional solid state reaction method. Crystal structure, morphology and luminescence properties (excitation, emission and CIE coordinate) of these phosphors have been studied as a function of sintering temperature and Eu³⁺ concentration. X-ray diffraction study reveals that the phosphor sintered at low temperature (900 °C) contains an impurity phase which is removed at higher sintering temperatures and results into cubic crystalline phase of Sr₃Ga₂O₆. Particle size of the phosphor increases with an increase in sintering temperature which results to a red shift in the peak position of excitation band lying in a broad range from 250 to 370 nm. Optimum emission intensity is attained for 0.12 mol% concentration of Eu³⁺ ions; above this concentration, a quenching in emission intensity is observed.     

溶胶-凝胶法合成掺铕硼酸镧钙荧光粉及其表征

首次采用溶胶-凝胶法制备Eu:La<,2>CaB<,10>O<19>,借助XRD、SEM和荧光光谱仪等测试手段对荧光粉进行表征与分析.结果表明,煅烧温度对产物的物相有较大影响,700℃煅烧前驱体12 h便具有单一晶相;800℃煅烧前驱体12 h得到的荧光粉,粒径为100 nm左右;用溶胶-凝胶制备的Eu:La<,2>L...     

用于白光LED的Sr_3SiO_5:Eu~(3+)材料制备及发光特性(英文)

采用高温固相法制备了Sr3SiO5:Eu3+材料.测量了Sr3SiO5:Eu3+材料的激发与发射光谱:材料的发射光谱由576、585、611、618nm和650nm几个发射峰组成,分别对应于Eu3+的5D0→7F0、5D0→7F1、5D0→7F2、5D0→7F2和5D0→7F3辐射跃迁.监测618 nm主发射峰时所得激发光谱为一多峰宽谱,主峰分别为400nul和470nm.研究了Eu"浓度对Sr3Si05:Eu3'材料发光强度的影响,结果显示:随Etl3'浓度的增大,发光强度先增大后减小,Eu3+的摩尔分数为3%时,材料的发光强度最大,根据Dexter理论,其浓度猝灭机理为电偶极一偶极跃迁.引入电荷补偿剂Cl-、Li+、Na+和K+时,材料的发光强度均得到了提高,其中Cl-和Li+的提高幅度较明显.     

Cathodoluminescence and thermoluminescence of ZnB2O4:Eu3+ phosphors prepared via wet-chemical synthesis

In present work, a series of Eu doped zinc borate, ZnB₂O₄, phosphors prepared via wet chemical synthesis and their structural, surface morphology, cathodoluminescence (CL) and thermoluminescence (TL) properties have been studied. Phase purity and crystal structure of as-prepared samples are confirmed by X-ray diffraction measurements (XRD) and they were well consistent with PDF card No. 39-1126, indicating the formation of pure phase. The thermoluminescence (TL) behaviors of Eu activated ZnB₂O₄ host lattice are studied for various beta doses ranging from 0.1 to 10?Gy. The high-temperature peak of Eu activated sample located at 192?°C exhibited a linear dose response in the range of 0.1–10?Gy. Initial rise (IR) and peak shape (PS) methods were used to determine the activation energies of the trapping centres. The effects of the variable heating rate on TL behaviour of Eu activated ZnB₂O₄ were also studied. When excited using an electron beam induced light emission (i.e cathodoluminescence, CL) at room temperature (RT), the as-prepared phosphors generate reddish-orange color due to predominant emission peaks of Eu³⁺ ions located at 576–710?nm assigned to the ⁵D₀→⁷F_J (J=1,2,3, and 4) transitions. The maximum CL intensity for Eu³⁺ ions at 614?nm with transition ⁵D₀→⁷F₂ was reached Eu³⁺ concentration of 5?mol%; quenching occurred at higher concentrations. Strong emission peak for Eu³⁺ ions at 614?nm with transition ⁵D₀→⁷F₂ is observed. The CL experimental data indicate that ZnB₂O₄:Eu³⁺ phosphor as an orange-red emitting phosphor may be promising luminescence materials for the optoelectronic applications.     

Anomalous enhancement of photoluminescence intensity of sintered YAG:Ce particles‐embedded glasses

For high‐power white LED applications, YAG:Ce‐based yellow phosphors were embedded in a low‐T_g Bi₂O₃–B₂O₅–ZnO–Sb₂O₅ glass by sintering route. Effects of sintering temperature (325‐390°C) on the microstructure and photoluminescence properties were investigated. X‐ray diffraction was used to measure the retained fraction of YAG:Ce phase after sintering. Scanning electron microscope and transmission electron microscope, equipped with energy‐dispersive X‐ray spectrometry, were used to examine the microstructure, including the element distribution across the phosphor–glass interface. Photoluminescence properties of the samples before and after sintering were compared. With the increasing sintering temperature, the retained fraction of YAG:Ce decreased from 83.3% to 82%. This effect tends to reduce the luminescence intensity of the samples after sintering. The increasing sintering temperature also enhances the diffusion of cations (esp. Bi) from glass matrix to YAG:Ce. This effect tends to increase the luminescence intensity of the YAG:Ce particles after sintering. When the sintering temperature was lower (325°C), the effect of YAG:Ce loss was dominant, thus the luminescence intensity was reduced after sintering. When the sintering temperature was higher (350‐390°C), the effect of solute dissolution was dominant, resulting in luminescence intensity anomalously higher than that before sintering. Similar result has not been reported in literatures. The maximum luminescence intensity of the sintered samples is 1.57 times as high as that of the samples before sintering.     

Photoluminescence properties and energy transfer between activators at different crystallographic sites in Ce3+ doped Sr2MgAl22O36

In this paper, a series of Ce3+ doped Sr₂MgAl₂₂O₃₆ (SMA) phosphors have been prepared by high temperature solid-state reaction method. The phase structure of prepared samples was checked by the powder X-ray diffraction (XRD). The morphology of the samples was inspected using a field-emission scanning electron microscope (SEM). Under different UV radiation, this phosphor exhibits different emission bands due to the Ce³⁺ ions located at different lattice sites. The corresponding luminescence and energy transfer mechanisms have been proposed in detail. The phosphor exhibits different concentration quenching mechanisms because the Ce³⁺ ions substitute two different crystallographic sites in the host. Moreover, the temperature dependent emission properties of SMA:Ce³⁺ were conducted from 30 °C to 200 °C, as much as 72.96% of the room-temperature emission intensity is retained at 150 °C. The SMA:Ce³⁺ phosphor exhibits bright blue emission with CIE coordinates (x=0.16, y=0.12) under UV excitation. The results indicate that SMA:Ce³⁺ phosphor has great potential applications in UV-pumped light emitting diodes.     

Synthesis and Luminescence Properties of Y3Al5O（12）：Eu^（3＋） Phosphors under Vacuum Ultraviolet Excitation

采用凝胶–燃烧法合成了掺Eu3＋的Y3Al5O12（YAG：Eu3＋）荧光粉。分别采用X射线衍射（XRD）、扫描电子显微镜（SEM）、发光光谱等测试手段分析了不同温度下煅烧所得粉体的物相、形貌与发光性质。XRD和SEM结果表明：YAG：Eu3＋的最低合成温度为900℃,并且在该反应过程中没有中间相YAP（YAlO3）和YAM（YAl）的产生。1 100℃合成的晶粒尺寸比较均匀,平均粒径在90 nm左右。发光光谱的测试表明：在592 nm监控下的真空紫外激发光谱由峰值位于147、156、169nm和214nm的系列激发带组成,其分别归属于铝酸根的基质吸收以及Y3＋和Eu3＋的电荷迁移带吸收。在147nm激发下YAG：Eu3＋荧光粉最强发射峰位于592nm处,属于Eu3＋的5D0→7F1跃迁。Eu3＋在基质中的最佳掺杂摩尔分数为4%。