Al~(3+)掺杂ScVO_4∶Eu~(3+),Bi~(3+)荧光粉的制备及发光性质

采用高温固相法在1 000℃下煅烧6 h合成了Sc VO4∶Eu3+,Bi3+,Al3+荧光粉。使用X射线粉末衍射仪和扫描电镜对样品的结构和形貌进行了表征,采用荧光分光光度计研究了样品的发光性质。用315 nm波长激发Sc VO4∶Eu3+,Bi3+,Al3+样品时,样品在590~620 nm范围内发射强烈的橙红光,最大发射峰位于615nm。少量Al3+的掺入可以增强Sc VO4∶Eu3+,Bi3+荧光粉的发光,而掺入过量Al3+时会使Sc VO4∶Eu3+,Bi3+荧光粉的发光变弱。当Al3+在Sc VO4∶Eu3+,Bi3+中的摩尔分数达到4%时,样品的发光最强且其发光强度较未掺杂Al3+的样品提高了约30%。     

Eu3+掺杂CaMoO4微米荧光粉发光性质的研究

运用化学沉淀的方法合成了不同Eu³⁺掺杂浓度CaMoO₄微米荧光粉样品, 详细研究了样品的光致发光性质. 研究表明: CaMoO₄: Eu可以被蓝光或近紫外光有效激发, 实现高色纯度的红光发射; 样品的黄昆因子数值数量级为10^-2, 是一种弱电声耦合材料; 样品中Eu³⁺的跃迁强度参数(Ω₂)随着掺杂浓度的提高而增大, 但量子效率却随着掺杂浓度的提高而减小; 通过对样品发光的浓度猝灭曲线的分析, 确定Eu³⁺的理想掺杂浓度为25%, 并判断出Eu³⁺在CaMoO₄基质中通过交换相互作用实现能量传递. 沉淀法制备的CaMoO₄: Eu微米荧光粉具有发光色纯度好, 制备工艺简单, 耗时较少的优点, 是一种性能优异的红色荧光粉材料.     

CaMoO4：Eu3+,Bi3+,Li+红色荧光粉的共沉淀制备与表征

采用共沉淀法合成了红色荧光粉Ca_0.75MoO₄：Eu_0.25³⁺、Ca_0.75MoO₄：Eu_0.25-x³⁺,Bi_x³⁺及Ca_0.5MoO₄：Eu_0.25-2x³⁺, Bi_x³⁺,Li_0.25+x⁺,并采用X射线衍射(XRD)、拉曼光谱,扫描电镜(SEM)和荧光光谱(PL)测定分析了其结构形貌特征及发光性能。结果表明：制备的CaMoO₄：Eu³⁺,Bi³⁺,Li⁺红色荧光粉为白钨矿结构,颗粒尺寸约为0.5~1 μm。掺杂Bi³⁺的Ca_0.75MoO₄：Eu_0.25-x³⁺,Bi_x³⁺的相对发光强度明显高于未掺Bi³⁺的Ca_0.75MoO₄：Eu_0.25³⁺荧光粉。Bi³⁺离子的掺杂将吸收来的能量传递给激活离子Eu³⁺,起到了能量传递的作用。当Bi³⁺掺杂量为x=0.005时,在395 nm激发下,主发射峰在616 nm处的相对发光强度最大,但掺杂浓度过高时会出现浓度猝灭现象。另外,电荷补偿剂的掺入能够解决材料中因同晶取代引起的电荷不平衡的问题,以Li⁺作电荷补偿剂、Eu³⁺和 Bi³⁺共掺合成的Ca_0.5MoO₄：Eu³⁺_0.23,Bi_0.01³⁺,Li⁺_0.26红色荧光粉的发光性能强于Ca_0.75MoO₄：Eu_0.25³⁺、Ca_0.5MoO₄：Eu_0.25³⁺, Li_0.25⁺及Ca_0.75MoO₄：Eu_0.24³⁺,Bi_0.01³⁺。     

花状NaY(MoO4)2的合成和(MoO4)2:Eu3+的光学性质

用微波辅助水热-煅烧法成功合成了花状NaY(MoO₄)₂颗粒,用XRD、XPS、FESEM进行了表征,提出了花状NaY(MoO₄)₂颗粒可能的形成机理. 采用相同的方法合成了NaY(MoO₄)₂:Eu³⁺荧光体,该荧光材料在612 nm处有一个强的发射峰,可用作白色发光二极管的红色磷光剂. 此外,微波辅助水热-煅烧法可能发展成为制备其他花状稀土钼酸盐的有效途径.     

Eu3+和Bi3+共掺杂锆酸钡荧光粉的制备及发光性质研究

在还原气氛下采用高温固相法制备了BaZrO₃∶0.05Bi,xEu(x=0, 0.010,0.025,0.050)荧光粉,并研究了其发光性能。研究证实：Bi,Eu共掺杂的BaZrO₃荧光粉在近紫外340 nm 激发下,具有来自于Bi3+的宽带发射峰和Eu3+的特征发射;Bi3+对Eu3+具有能量传递和敏化作用,通过Bi3+和Eu3+之间的能量传递获得了具有白色发光的BaZrO₃荧光粉。     

Dy3+ emission in M5(PO4)3F (M = Ca, Ba) phosphor

Ultrafine M₅(PO₄)₃F:Dy³⁺ (M = Ca, Ba) phosphors were prepared via combustion process using metal nitrates as precursors. The formation of crystalline phosphate was confirmed by X-ray diffraction pattern. The PL excitation spectra show the excitation peaks observed at 250 to 400 nm due to f → f transition of Dy³⁺ ion, which are useful for solid-state lighting purpose (mercury free excitation). The PL emission of Dy³⁺ ion by 348 nm excitation gave an emission at 489 nm (blue), 582 nm (yellow) and 675 nm (red). All the characteristics of BYR emissions like BGR indicate that Dy doped Ca₅(PO₄)₃F and Ba₅(PO₄)₃F phosphors are good candidates that can be applied in solid-state lighting phosphor (mercury free excited lamp phosphor) and white light LED.      

纳米晶ZrO2：Eu3＋-Bi3＋的制备及Bi3＋敏化Eu3＋特征发射的研究

采用化学共沉淀法制备了纳米晶ZrO2：Eu3＋-Bi3＋粉体,所制备的纳米晶粉体均能观测到Eu3＋离子的室温特征发射．研究了样品的晶体结构和发光性质．结果表明：经600℃煅烧后得到的纳米晶ZrO2：Eu3＋-Bi3＋粉体的晶相为四方相,经800,950及1100℃煅烧后的样品为四方相和单斜相的混合晶相．Eu3＋离子在四方相中的室温特征发射明显强于在混合相中的发射．Bi3＋离子的掺入对Eu3＋离子的室温特征发射有显著的敏化作用．     

白光发光二级管用红色荧光粉LiSrBO3: Eu3+的制备与发光性能研究

采用高温固相法制备了LiSrBO₃:xEu³⁺ 荧光粉, 并通过XRD, 红外(FITR) 和荧光光谱(PL) 等对其表征. 结果表明, LiSrBO₃: Eu³⁺ 荧光粉可被波长为395 nm 的紫外线和466 nm 的蓝光有效激发, 且发射主波长为612 nm (Eu³⁺的电偶极跃迁⁵D₀ →⁷F₂) 的红光. 研究了Eu³⁺ 掺杂浓度对LiSrBO₃: Eu³⁺ 材料发光强度的影响, Eu³⁺ 掺杂浓度为6% 时样品的发射强度最大, 并且证实Eu³⁺ 之间的能量传递机制为电偶极子- 电偶极子相互作用. Li⁺, Na⁺, K⁺ 作为电荷补偿剂的引入全部导致LiSrBO₃: Eu³⁺ 材料发射强度增强, 其中, Li⁺ 的引入要优于Na⁺ 和K⁺. 少量Al³⁺的掺杂降低了Eu³⁺ 所处格位的对称性, 增强了Eu³⁺ 的612 nm 的电偶极发射, 改善了LiSrBO₃: Eu³⁺ 红色材料的色纯度. 关键词： 白光发光二级管 光致发光 浓度猝灭 电荷补偿剂     

SrZn2(PO4)2:Sn2+,Mn2+荧光粉的发光性质及其能量传递机理

采用高温固相法制备了SrZn₂(PO₄)₂:Sn²⁺(SZ₂P:Sn²⁺), SrZn₂(PO₄)₂:Mn²⁺(SZ₂P:Mn²⁺), SrZn₂ (PO₄)₂:Sn²⁺, Mn²⁺(SZ₂P:Sn²⁺, Mn²⁺) 荧光粉. 通过X射线衍射、激发和发射光谱详细研究了荧光粉的物相和发光性质. 在SrZn₂(PO₄)₂ 基质中, Sn²⁺离子发射光谱是峰值位于461 nm宽带谱, 归属于Sn²⁺离子的³P₁→¹S₀能级跃迁, SZ₂P:Mn²⁺激发光谱由基质吸收带(200–300 nm)和位于352, 373, 419, 431和466 nm的一系列激发峰组成, 分别对应Mn²⁺离子的⁶A₁(⁶S)→⁴E(⁴D), ⁶A₁(⁶S)→⁴T₂(⁴D), ⁶A₁(⁶S)→[⁴A₁(⁴G), ⁴E(⁴G)], ⁶A₁(⁶S)→⁴T₂(⁴G)和⁶A₁(⁶S)→⁴T₁(⁴G)能级跃迁, 因此, SZ₂P:Sn²⁺ 的发射光谱与SZ₂P:Mn²⁺的激发光谱有较大范围的重叠. 结果表明Sn²⁺对Mn²⁺发光有明显的敏化作用. 基于Dexter电多极相互作用能量传递公式和Reisfeld近似原理分析, 荧光粉SZ₂P:Sn²⁺, Mn²⁺中Sn²⁺-Mn²⁺离子之间的能量传递机理属于电四极-电四极相互作用引起的共振能量传递, 并计算出Sn²⁺-Mn²⁺离子之间能量传递临界距离R_c ≈ 1.78 nm. 通过改变Sn²⁺, Mn²⁺离子掺杂浓度, 实现了荧光粉发光颜色的调节, 在254 nm短波紫外激发下荧光粉发出较强的蓝白光. 研究结果表明SZ₂P:Sn²⁺, Mn²⁺荧光粉有望应用于紧凑型节能灯照明领域, 随着半导体紫外芯片技术的发展, 有潜力应用于未来的白光发光二极管照明领域.     

Eu^2＋：Sr9Ca（PO4）6Cl2中的新型色心及其光激励发光

本文报道了Ｅｕ＾２＋：Ｓｒ９Ｃａ（ＰＯ４）６Ｃｌ２的新型色心。它的吸收带主峰分别位于７０８，７８５，８４５及９９０ｎｍ。用对应于Ｆ心吸收带和这些吸收带波长的光束分别激励样品时得到相同的光激励发光。通过对比研究表明，这些吸收带是由Ｆ心的缔合中心，即由ＦＡ心产生的。由于这些色心的吸收带偏离Ｅｕ＾２＋的发射波长（４５０ｎｍ）更远，故更适应于Ｅｕ＾２＋：Ｓｒ９Ｃａ（ＰＯ４）６Ｃｌ２光波励发光的研究和开发。     

BaGd2(MoO4)4:Tb3+,Eu3+荧光粉的 发光特性与能量传递机理

利用高温固相法制备了BaGd_2(MoO_4)_4∶Tb~(3+)与BaGd_2(MoO_4)_4∶Tb~(3+),Eu~(3+)荧光粉,并借助于X射线衍射(XRD)、激发光谱、发射光谱及荧光衰减曲线对样品的结构及发光性能进行了表征。在290 nm激发下,BaGd_2(MoO_4)_4∶Tb~(3+)样品在550 nm处具有较强的绿光发射,表明该样品可用作绿色荧光粉。Tb~(3+)离子的最佳掺杂浓度为50%,电偶极间相互作用是引起浓度猝灭效应的主要原因。当在BaGd_2(MoO_4)_4∶Tb~(3+)荧光粉中共掺入Eu~(3+)离子后,可同时观测到Tb~(3+)与Eu~(3+)离子的特征发射峰。随Eu~(3+)掺杂浓度的升高,Tb~(3+)离子的发光强度逐渐下降,而Eu~(3+)离子的发光强度逐渐增加。根据BaGd_2(MoO_4)_4∶Tb~(3+),Eu~(3+)中Tb~(3+)离子的荧光寿命计算了Tb~(3+)与Eu~(3+)离子间的能量传递效率,并根据荧光寿命与激活离子掺杂浓度的关系证实了能量传递机制为电偶极间相互作用。     

Luminescence properties of Eu2+ in M2MgSi2O7 (M=Ca, Sr, and Ba) phosphors

The photoluminescence properties of alkali-earth magnesium silicates (M₂MgSi₂O₇, M=Ca, Sr, and Ba) doped with Eu²⁺ were investigated. Solid solutions of Ba _x Sr_2−x Si₂O₇, Ca₂MgSi₂O₇, and Sr₂MgSi₂O₇ were prepared. Ba _x Sr_2−x Si₂O₇ retained a tetragonal crystal structure similar to the structure of the other compounds up to a stoichiometry of x=1.6, which enabled a systematic study of the common structure. Monoclinic Ba₂MgSi₂O₇ was prepared, and the luminescence properties were compared with those of other samples. The emission and excitation spectra of tetragonal M₂MgSi₂O₇ (M=Ca, Sr, and Ba) changed as a function of the covalency, site symmetry, and crystal field strength. The luminescence properties showed excellent agreement with theoretical predictions based on these factors. The Stokes shift differentiated the emission behaviors of the tetragonal and monoclinic structures.     

Eu3+/Dy3+共掺Sr3Y2(BO3)4荧光粉的发光性质研究

稀土掺杂发光材料一直是科研领域研究的热点,被广泛应用于白光LED、温度传感、显示显像、新能源和激光等领域。基质的结构对于稀土离子光致发光特性有非常重要的影响,在众多发光基质材料中,硼酸盐具有透光范围宽、光学损伤阈值高、较好的热稳定性和化学稳定性等优点。碱土-稀土金属硼酸盐Sr₃Y₂(BO₃)₄具有出色的光学性能,对其发光性能的研究具有重要意义。稀土离子Eu³⁺具4f⁶电子层,是一种典型的下转换发光中心离子,常被选作红色发光材料的激活剂。Dy³⁺具4f⁹电子层,也是一种典型的下转换发光中心离子,在紫外光激发下,在蓝色光区和橙色光区有较强的荧光发射。采用高温固相法合成了Sr₃Y₂(BO₃)₄∶Eu³⁺/Dy³⁺荧光粉,通过XRD和SEM对样品的结构和形貌进行了表征,XRD结果表明,1 0...     

Luminescence and energy transfer in Y2O3 CO-doped with Bi3+ and Eu3+

The emission spectra and decay times of the Y₂O₃ CO-doped with Bi³⁺ and Eu³⁺ have been investigated using site-selective excitation and time-resolved spectroscopy in the temperature range 8–296 K. Evidence for an energy transfer from Eu³⁺(S₆) to Eu³⁺(C₂) is given. The critical transfer distance R₀ = 8.6 Å was found from the decay curve.     

正磷酸盐晶体Ba3(PO4)2和Sr3(PO4)2高温拉曼光谱研究

测量了碱土金属正磷酸盐Ba₃(PO₄)₂和Sr₃(PO₄)₂常温及高温拉曼光谱, 对拉曼振动模式进行指认, 并分析了晶体拉曼振动光谱及晶体结构在高温下的变化. 在温度升高的过程中, 拉曼振动频率向低频移动且振动峰宽度展宽, 晶体中的P-O平均键长随温度升高而变长, 但O-P-O的键角并未发生变化. 晶体在900 ℃以下无结构相变发生. 关键词： 3(PO₄)₂和Sr₃(PO₄)₂')" href="#">Ba₃(PO₄)₂和Sr₃(PO₄)₂ 高温拉曼光谱 振动模式 高温结构     

High-pressure Raman spectroscopic studies on orthophosphates Ba3(PO4)2 and Sr3(PO4)2

By using diamond anvil cell (DAC), high-pressure Raman spectroscopic studies of orthophosphates Ba₃(PO₄)₂ and Sr₃(PO₄)₂ were carried out up to 30.7 and 30.1 GPa, respectively. No pressure-induced phase transition was found in the studies. A methanol:ethanol:water (16:3:1) mixture was used as pressure medium in DAC, which is expected to exhibit nearly hydrostatic behavior up to about 14.4 GPa at room temperature. The behaviors of the phosphate modes in Ba₃(PO₄)₂ and Sr₃(PO₄)₂ below 14.4 GPa were quantitatively analyzed. The Raman shift of all modes increased linearly and continuously with pressure in Ba₃(PO₄)₂ and Sr₃(PO₄)₂. The pressure coefficients of the phosphate modes in Ba₃(PO₄)₂ range from 2.8179 to 3.4186 cm⁻¹ GPa⁻¹ for ν₃, 2.9609 cm⁻¹ GPa⁻¹ for ν₁, from 0.9855 to 1.8085 cm⁻¹ GPa⁻¹ for ν₄, and 1.4330 cm⁻¹ GPa⁻¹ for ν₂, and the pressure coefficients of the phosphate modes in Sr₃(PO₄)₂ range from 3.4247 to 4.3765 cm⁻¹ GPa⁻¹ for ν₃, 3.7808 cm⁻¹ GPa⁻¹ for ν₁, from 1.1005 to 1.9244 cm⁻¹ GPa⁻¹ for ν₄, and 1.5647 cm⁻¹ GPa⁻¹ for ν₂.     

一种LED用红色荧光粉BaZn2(BO3)2：Eu3+的合成与发光性能研究

通过高温固相法制得双峰可调节本征半导体发光BaZn₂（BO₃）₂：Eu³⁺荧光粉,此类荧光粉在300~400 nm的紫外波段有很强的吸收。在375 nm的紫外光激发下,该荧光粉产生了两个宽带的发射峰,分别位于550 nm和615 nm处。并且,在395 nm的紫光激发下,荧光粉会由于Eu³⁺离子的⁵D₀→⁷F₂电偶极跃迁产生一个位于615 nm的强宽发射峰,这表明Eu³⁺离子占据了反演对称中心的位置,取代了BaZn₂（BO₃）₂中部分的Ba²⁺离子。当Eu³⁺的摩尔分数达到10%时,发生浓度猝灭。在不同浓度的Eu³⁺离子的掺杂下,BaZn₂（BO₃）₂：Eu³⁺荧光粉的发光从黄色延伸到红色,实现了荧光粉的色度可调。     

On some new green emitting phosphors with Sr3 (PO4)2 type structure

New sodium strontium rare-earth orthophosphates with general formula Na_xSr_3?2xLn_x (PO₄)₂ (Ln = La, Nd, Gd) have been prepared and characterized. They seem to be of Sr₃ (PO₄)₂ structural type. In NaSrLa_1?x?yCe_xTb_y (PO₄)₂, a new green phosphor absorbing in the UV region, high yield results from a Ce³⁺ → Tb³⁺ energy transfer.     

ESR of Cu2+ in the high pressure form of Cd3(PO4)2

ESR spectra of polycrystalline Cu²⁺ doped samples of the high pressure phase of Cd₃(PO₄)₂ were characteristic of the existence of two different paramagnetic centres. The spin—Hamiltonian constants of both defects were determined. Only two of the three possible substitutional cation sites are occupied by copper ions.     

Gd2O3:Eu3+纳米晶的燃烧合成及光致发光性质

采用柠檬酸作燃烧剂用燃烧合成法制备了Gd₂O₃:Eu³⁺纳米晶.用X射线衍射仪(XRD)、高分辨透射电子显微镜(HRTEM)和荧光分光光度计等对Gd₂O₃:Eu³⁺纳米晶的结构、形貌和发光性能进行了分析.结果表明：不同柠檬酸与稀土离子配比(C/M)制备的样品经800℃ 退火1 h后，均得到了纯立方相的Gd₂O₃:Eu³⁺纳米晶，晶粒尺寸约为30 nm，尺寸分布较窄，其中以C/M=1.0时制备的纳米晶结晶性最好，发光强度最大.Gd₂O₃:Eu³⁺纳米晶主发射峰位置均在612 nm处 (⁵D₀→⁷F₂跃迁)，激发光谱中电荷迁移态发生红移，观察到Gd³⁺向Eu³⁺的有效能量传递.对柠檬酸与稀土离子配比(C/M)对结晶度、发光性质等的影响也进行了分析和讨论.