GdF3∶Eu3+和NaGdF4∶Eu3+发光粉的可控合成与发光性质

采用聚乙烯吡咯烷酮(PVP)辅助水热法合成了GdF3∶Eu3+和NaGdF4∶Eu3+发光粉。利用X射线衍射(XRD)、扫描电子显微镜和荧光光谱对样品的结构、形貌和发光性能进行了研究。XRD分析表明:GdF3晶相到NaGdF4晶相的转换可以通过改变初始溶液pH值、PVP加入量和NaF与稀土离子(Gd3+和Eu3+)摩尔配比等合成条件实现。NaGdF4∶Eu3+发光粉的形貌受合成条件的影响。荧光光谱研究表明:GdF3∶Eu3+发光粉主发射峰位于593nm处,来自于Eu3+的5 D0→7 F1磁偶极跃迁;NaGdF4∶Eu3+发光粉主发射峰位于616nm,来自于Eu3+的5 D0→7 F2电偶极跃迁。2个样品中Gd3+与Eu3+离子之间存在较好的能量传递,而NaGdF4晶格更有利于2种离子的能量传递。     

Ligand-Sensitised LaF3:Eu3+ and SrF2:Eu3+ Nanoparticles and in Vitro Haemocompatiblity Studies

Luminescent Ln³⁺-doped nanoparticles (NPs) functionalised with the desired organic ligand molecules for haemocompatibility studies were obtained in a one-pot synthesis. Chelated aromatic organic ligands such as isophthalic acid, terephthalic acid, ibuprofen, aspirin, 1,2,4,5-benzenetetracarboxylic acid, 2,6-pyridine dicarboxylic acid and adenosine were applied for surface functionalisation. The modification of the nanoparticles is based on the donor–acceptor character of the ligand–nanoparticle system, which is an alternative to covalent functionalisation by peptide bonding as presented in our recent report. The aromatic groups of selected ligands absorb UV light and transfer their excited-state energy to the dopant Eu³⁺ ions in LaF₃ and SrF₂ NPs. Herein, we discuss the structural and spectroscopic characterisation of the NPs and the results of haemocompatibility studies. Flow cytometry analysis of the nanoparticles’ membrane-binding is also presented.     

氧化物玻璃中Eu~(3＋)离子的发光研究

应用荧光光谱、红外振动光谱和差热分析等研究了Ｅｕ３＋离子在不同氧化物玻璃基质中的发光行为。结果表明：不同氧化物玻璃基质对Ｅｕ３＋离子的激发谱和发光谱的峰位影响很小，发光强度按硅酸盐、硼酸盐、钡磷酸盐、铝磷酸盐玻璃顺序递增。玻璃中Ｅｕ３＋激活离子与最邻近配位体之间共价键因素引起的近距离作用对无辐射跃迁过程影响比多声子驰豫更强烈，讨论了氧化物玻璃配位体对Ｅｕ３＋离子的极化作用与发光强度的关系。     

表面改性剂对CaCO3:Eu3+荧光粉发光性能的影响

采用微波共沉淀法制备了CaCO3:Eu3+红色荧光粉,然后分别用硬脂酸和钛酸酯偶联剂(TC-114)对其进行改性,研究改性前后荧光粉的结构和发光性能的变化。激光粒度和X射线衍射分析表明,经硬脂酸改性后的荧光粉粒径有所增加,而经钛酸酯偶联剂改性后的荧光粉粒径有所减小,改性前后结构未发生变化。红外光谱与热重分析表明,硬脂酸和钛酸酯偶联剂与荧光粉表面羟基发生了化学键合。荧光光谱测试表明,经硬脂酸改性的CaCO3:Eu3+红色荧光粉荧光强度增强,而经钛酸酯偶联剂改性后其荧光强度明显减弱,可能是由改性剂自身结构以及改性前后荧光粉表面的羟基数量和猝灭中心数量不同所致。     

Combustion Synthesis and Enhancement of BiOCl by Doping Eu3+ for Photodegradation of Organic Dye

Eu³⁺‐doped BiOCl with different doping concentrations was synthesized by a simple combustion method. The as‐synthesized photocatalysts were characterized by X‐ray diffraction, scanning electron microscope, transmission electron microscope, Raman spectroscopy, X‐ray photoelectron spectroscopy, electron paramagnetic resonance spectroscopy, and UV–vis diffuse reflectance spectroscopy. The experimental results show that Eu³⁺ was successfully doped into the lattice of BiOCl. The as‐synthesized Eu³⁺‐doped BiOCl photocatalysts show a more intense continuous absorption in UV light region, accompanied with decreased energy band gap. Moreover, the Eu³⁺ doping leads to the formation of oxygen vacancies, small crystallite size, and high specific surface areas. Compared with pure BiOCl, the Eu³⁺‐doped BiOCl photocatalysts exhibits much higher photocatalytic activity for Rhodamine B (RhB) under UV light irradiation. As‐obtained Eu³⁺‐doped BiOCl can be easily reused with excellent stability. In addition, the mechanism of the improved photocatalytic properties of Eu³⁺‐doped BiOCl was discussed in detail.     

Eu3+掺杂磷酸盐的燃烧法合成及发光性质

本文以磷酸盐荧光材料作为研究对象,采用燃烧法制备了不同基质的红色荧光粉,红色荧光粉可以改善光色、提高显色指数,一直是研究的热点.室温下用X射线衍射仪测定了其晶体结构,用F-4600测定了其光致发光性质.结果表明合成的Lu12P2O23∶ Eu3,YP5O14∶Eu3+与La3 PO7∶Eu3+均属单斜相结构,Eu3+在单斜结构基质中占据非对称性格位.在完全相同实验条件下,对不同基质下掺杂Eu3+离子的发光强度进行比较,同时还研究了不同的Eu3浓度对La3PO7发光性质的影响.     

Synthesis of YVO4:Eu3+/YBO3 Heteronanostructures with Enhanced Photoluminescence Properties

Novel YVO₄:Eu³⁺/YBO₃ core/shell heteronanostructures with different shell ratios (SRs) were successfully prepared by a facile two-step method. X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy were used to characterize the heteronanostructures. Photoluminescence (PL) study reveals that PL efficiency of the YVO₄:Eu³⁺ nanocrystals (cores) can be improved by the growth of YBO₃ nanocoatings onto the cores to form the YVO₄:Eu³⁺/YBO₃ core/shell heteronanostructures. Furthermore, shell ratio plays a critical role in their PL efficiency. The heteronanostructures (SR = 1/7) exhibit the highest PL efficiency; its PL intensity of the ⁵D₀–⁷F₂ emission at 620 nm is 27% higher than that of the YVO₄:Eu³⁺ nanocrystals under the same conditions.     

单分散GdxY2-xO3：Eu^3＋纳米颗粒的制备及其荧光性能

本文采用均相沉淀法制备了单分散GdxY2-xO3:Eu3 纳米颗粒,并利用SEM,TEM,XRD和荧光光谱对产品的形貌,晶体结构和荧光性能进行了表征.结果发现适量Gd3 的加入对Y2O3:Eu3 的发光具有显著的增强作用.同时达到最大荧光强度所需的价格较贵的Gd3 用量,也从燃烧法的80%大幅减少到20%.另外,本文还进一步研究了Eu3 浓度对纳米颗粒荧光性能的增强效果.     

Eu^3＋、Dy^3＋对CaTiO3：Pr^3＋红色磷光体发光性能的影响

采用改进高温固相法合成了掺杂Eu3+和Dy3+作为共激活离子的红色长余辉磷光体,详细阐述了Eu3+、Dy3+对CaTiO3:Pr3+红色磷光体发光性能的影响.通过X-射线衍射仪和电子扫描显微镜对所得样品的晶相类型及表面形态进行了表征,结果发现,在一定灼烧温度下,Eu3+或/和Dy3+对晶相的作用是协同的,且Eu3+或/和Dy3+对CaTiO3:Pr3+红色磷光体的粒径也有影响.室温条件下采用荧光/磷光发光光度计对其发光性能进行测定,结果表明,一定量的Eu3+或/和Dy3+能显著改善CaTiO3:Pr3+红色磷光体的发光性能.     

燃烧法合成掺铕硼酸镧钙荧光粉及其发光性能研究

采用燃烧法合成Eu：La2CaB10O19荧光体,用XRD、SEM并研究了所得荧光粉的形态、粒度和物相,用荧光分光光度计测定了荧光粉的发光性能并与高温固相法制备的粉体对比。结果表明Eu：La2CaB10O19荧光体的晶体结构属于单斜晶系结构。燃烧后所得的前驱体样品在800℃下烧结1.5 h便具有很好的晶相,制备产物粒度在300 nm左右,在395 nm激发下的发射强度跟高温固相法制备的Eu：La2CaB10O19强度接近。     

Preparation and Enhanced Luminescence of Au Nanoparticles Including SiO2:Tb3+ Three‐Dimensional Ordered Macroporous Films

Novel photoluminescent films consisting of three‐dimensionally ordered macroporous (3DOM) SiO₂:Tb³⁺ and Au nanoparticles were prepared by template assisted method, and their luminescence properties were investigated. The results show that Au nanoparticles have significant influence on luminescence property of SiO₂:Tb³⁺ 3DOM materials. The Au nanoparticles embedded in the skeleton of SiO₂:Tb³⁺ 3DOM materials could strongly improve their luminescence properties. The enhancement mechanism was discussed and demonstrated, which is attributed to the increasing of radiative decay rates of Tb³⁺ induced by surface plasmon effects of Au nanoparticles.     

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。     

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.     

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.     

Strong Eu2+ light emission in Eu silicate through Eu3+ reduction in Eu2O3/Si multilayer deposited on Si substrates

Eu₂O₃/Si multilayer nanostructured films are deposited on Si substrates by magnetron sputtering. Transmission electron microscopy and X-ray diffraction measurements demonstrate that multicrystalline Eu silicate is homogeneously distributed in the film after high-temperature treatment in N₂. The Eu²⁺ silicate is formed by the reaction of Eu₂O₃ and Si layers, showing an intense and broad room-temperature photoluminescence peak centered at 610 nm. It is found that the Si layer thickness in nanostructures has great influence on Eu ion optical behavior by forming different Eu silicate crystalline phases. These findings open a promising way to prepare efficient Eu²⁺ materials for photonic application.     

Luminescence performance of yttrium-stabilized zirconia ceramics doped with Eu3+ ions fabricated by Spark Plasma Sintering technique

Yttrium stabilized zirconia (YSZ) ceramics doped with Eu³⁺ ions have been successfully fabricated by Spark Plasma Sintering (SPS) technique. The influence of the europium concentration and post-annealing process on the structural, optical, and luminescent properties of the ceramics has been studied. It is shown that an increase in the europium concentration from 0.1 to 3 wt% does not lead to significant changes in the transmission spectra. However, annealing in air atmosphere at temperature from 700 °C to 1300 °C significantly affects the transmission spectrum, as a possible consequenceofthe formation of oxygen vacancy defects. The analysis of the photoexcitation and photoluminescence spectra showed that the main excitation bands are determined by direct excitation of the ⁷F₀ ground state of Eu³⁺ions to the higher 4f energy levels with further radiation transitionsfrom these states. Moreover, the europium ion in the obtained ceramics occupy low-symmetry sites without inversion center.The luminescence decay kineticsare described by a doubleexponential function with decay time τ₁ ~ 20 ns and τ₂~ 90 ns for intrinsic emission centers and millisecond (τ ~ 1.4 ms) for Eu³⁺emission, for all investigated ceramics. The luminescence spectra in nanosecond time region are characteristic for yttrium-stabilized zirconia and are caused by oxygen vacancies in the presence of heavy cations (Y³⁺ and Eu³⁺).     

Synthesis,Crystal Structure,and Enhanced Luminescence of Garnet‐Type Ca3Ga2Ge3O12:Cr3+ by Codoping Bi3+

Garnet‐type compound Ca₃Ga₂Ge₃O₁₂ and Cr³⁺‐doped or Cr³⁺/Bi³⁺ codped Ca₃Ga₂Ge₃O₁₂ phosphors were prepared by a solid‐state reaction. The crystal structure of Ca₃Ga₂Ge₃O₁₂ host was studied by X‐ray diffraction (XRD) analysis and further determined by the Rietveld refinement. Near‐infrared (NIR) photoluminescence (PL) and long‐lasting phosphorescence (LLP) emission can be observed from the Cr³⁺‐doped Ca₃Ga₂Ge₃O₁₂ sample, and the enhanced NIR PL emission intensity and LLP decay time can be realized in Cr³⁺/Bi³⁺ codped samples. The optimum concentration of Cr³⁺ in Ca₃Ga₂Ge₃O₁₂ phosphor was about 6 mol%, and optimum Bi³⁺ concentration induced the energy‐transfer (ET) process between Bi³⁺ and Cr³⁺ ions was about 30 mol%. Under different excitation wavelength from 280 to 453 nm, all the samples exhibit a broadband emission peaking at 739 nm and the intensity of NIR emission increases owing to the ET behavior from Bi³⁺ to Cr³⁺ ions. The critical ET distance has been calculated by the concentration‐quenching method. The thermally stable luminescence properties were also studied and the introduction of Bi³⁺ can also improve the thermal stability of the NIR emission.     

Gd~(3+)/Si~(4+)掺杂对LiZnPO_4:Eu~(3+)荧光粉发光性能的影响

采用高温固相法制备了LiZnPO4:Eu3+红色荧光粉,分别研究了Eu3+掺量、Eu3+和Gd3+共掺杂以及SiO2掺杂对材料发光性能的影响。结果表明:在395nm近紫外光激发下,发射光谱峰值位于593nm,属于Eu3+的5D0→7F1辐射跃迁;激发光谱由200~280nm的宽带和310~500nm的一系列尖峰组成,分别对应于O2–→Eu3+电荷迁移带和Eu3+的f→f能级跃迁吸收,主激发峰位于395nm左右,与近紫外发光二极管(NUV-LED)的发射光谱(360~410nm)匹配。Eu3+最佳掺杂摩尔分数为12%,超过12%后发生浓度猝灭现象,浓度猝灭机理为电多极–电多极相互作用。掺杂Gd3+、SiO2使Eu3+在593nm处的发射分别增强了107%、105%。LiZnPO4:Eu3+是适合NUV-LED管芯激发的白光发光二极管用高亮度橙红色荧光粉。     

793 nm光激发下NaYF4:Eu3+上转换发光性能

利用水热法制备NaYF4:Eu3+的上转换发光材料,用荧光光谱、CIE色坐标和X射线粉末衍射表征样品的发光性质,探索影响上转换发光性能的要素:Eu3+的掺杂量,pH值,EDTA-2Na:Eu3+的摩尔比及Y3+:F-的摩尔比.结果表明:在793 nm激发下,Eu3+的掺杂量为14％,pH值为6,EDTA-2Na:Eu3...