纳米Ln2O3:Eu(Ln=Gd,Y)荧光粉的燃烧法合成及其光致发光性质

本文报道了用燃烧法制备的纳米（5～100nm）Gd2O3：Eu和Y2O3：Eu荧光粉，对它们的晶体结构和光致发光性质进行了研究．结果表明，纳米Gd2O3：Eu和Y2O3：Eu的光致发光性质与常规的Gd2O3：Eu和Y2O3：Eu的性质有很大的差别，纳米Gd2O3：Eu和Y2O3：Eu表现出很强的介观效应．对实验结果进行了初步的探讨．     

稀土(铕、铽)三元配合物的合成、表征与发光性能

合成了Eu(TFA)3(TPPO)2、Tb(TFA)3(TPPO)2三元配合物以及Eu1／2Tb1／2(TFA)3(TPPO)2三元双核配合物，并经元素分析、紫外-可见吸收光谱和红外透射光谱确认。研究了配合物的发光性质,发现了该三元体系配合物的摩擦发光现象,且三元双核配合物经摩擦发出明亮的白光。     

A general aqueous sol-gel route to Ln(2)Sn(2)O(7) nanocrystals

This paper describes a general aqueous sol-gel route for the synthesis of a series of rare earth stannates, Ln(2)Sn(2)O(7) (Ln = Y, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb and Lu), with pure pyrochlore phase via the assistance of a cetyltrimethyl ammonium bromide (CTAB) surfactant. The route involves first the formation of CTAB-inorganic lamellar structures and then their thermal decomposition at 800?°C to yield the pyrochlore Ln(2)Sn(2)O(7) nanocrystals. Techniques using a thermo-gravimetric/differential thermal analyzer (TG-DTA), x-ray diffraction (XRD) and transmission electron microscopy (TEM) as well as selected-area electron diffraction (SAED) have been employed to characterize the as-synthesized Ln(2)Sn(2)O(7) nanocrystals. Furthermore, photoluminescence (PL) of the 5% Eu(3+) activated Ln(2)Sn(2)O(7) nanocrystals and carbon monoxide catalytic oxidation over the as-obtained Ln(2)Sn(2)O(7) nanocrystals were investigated. The results indicate that the PL properties as well as the catalytic activity changes significantly with the ionic radii of the rare earth elements.     

Luminescence properties of nano-crystalline Ba3MgSi2O8:Eu2+, Mn2+ phosphors

Ba3MgSi2O8:Eu2+, Mn2+ phosphors were synthesized by the sol-gel method and high temperature solid-state reaction method, respectively. XRD (X-ray diffraction), FT-IR (Fourier transform infrared spectroscopy), PL (photoluminescence spectra), and PLE (photoluminescence excitation spectra) were measured to characterize the samples. Emission and excitation spectra of our Ba3MgSi2O8:Eu2+, Mn2+ phosphors monitored at 441, 515, and 614 nm are depicted in the paper. The emission intensities of 441 and 515 nm emission bands increase with increasing Eu2+ concentration, while the peak intensity of the 614 nm band increases with increasing Mn2+ concentration. We conclude that the 515 nm emission band is attributed to the 4f(6)5d transition of Eu2+ ions substituted by Ba2+ sites in Ba2SiO4. The 441 nm emission band originates from Eu2+ ions, while the 614 nm emission band originates from Mn2+ ions of Ba3MgSi2O8:Eu2+, Mn2+. Nano-crystalline Ba3MgSi2O8:Eu2+, Mn2+ phosphors prepared by the sol-gel method show higher color rendering and better color temperature in comparison with the samples prepared by high temperature solid-state reaction method.     

Y2O3∶Eu$1纳米晶的尺寸调控与发光性能研究

以尿素为沉淀剂,柠檬酸为表面活性剂,通过水热法得到了非晶态的水合硝酸氧钇前驱体,进一步烧结处理后生成了立方相Y2 O3纳米晶．利用X－射线衍射（ XRD）、扫描电镜（ SEM）、透射电镜（ TEM）、红外光谱（ FTIR）和荧光光谱（ PL）分别对所得样品的相结构、形貌粒度、表面结构以及发光性能进行研究．结果表明：当烧结温度从600℃升高到900℃,Y2 O3∶Eu3＋纳米颗粒的结晶性增强,并实现了粒径调控,由13．0 nm增加至27．9 nm．随着Y2 O3∶Eu3＋纳米颗粒尺寸的增加,比表面积减小会导致发光离子附近的表面晶格缺陷降低,同时纳米晶表面吸附水、硝酸根以及柠檬酸根等杂质离子逐渐被去除,减少了荧光猝灭中心,从而有利于增强荧光发射强度以及延长荧光寿命．     

Study on UV excitation properties of Y2O3:Ln3+ (Ln = Eu3+ or Tb3+) luminescent nanomaterials

Y2O3:Ln3+ (Ln = Eu or Tb) nanocrystals with different Ln3+ doping concentrations and average sizes were prepared by chemical self-combustion. The corresponding bulk materials with various doping concentrations were obtained by annealing the nanomaterials at high temperature. The emission spectra, excitation spectra, and X-ray diffraction spectra were used in this study. It was found that the charge transfer band of Y2O3:Eu3+ red-shifted as particle size decreased, and the charge transfer band in the 5-nm particles obviously broadened toward the long wavelength. It was also found that the profile of excitation spectra corresponding to the 4f5d (4f8 --> 4f(7)5d1) transition changed a lot with the variation of the particle size. The dependence of the excitation spectra of Y2O3:Ln3+ on particle size was investigated.     

Sol-gel fabrication and photoluminescence properties of SiO2 @ Gd2O3:Eu3+ core-shell particles

A uniform nanolayer of europium-doped Gd2O3 was coated on the surface of preformed submicron silica spheres by a Pechini sol-gel process. The resulted SiO2 @ Gd2O3:Eu3+ core-shell structured phosphors were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence (PL) spectra as well as kinetic decays. The XRD results show that the Gd2O3:Eu3+ layers start to crystallize on the SiO2 spheres after annealing at 400 degrees C and the crystallinity increases with raising the annealing temperature. The core-shell phosphors possess perfect spherical shape with narrow size distribution (average size: 640 nm) and non-agglomeration. The thickness of the Gd2O3:Eu3+ shells on the SiO2 cores can be adjusted by changing the deposition cycles (70 nm for three deposition cycles). Under short UV excitation, the obtained SiO2@Gd2O3:Eu3+ particles show a strong red emission with 5D0-7F2 (610 nm) of Eu3+ as the most prominent group. The PL intensity of Eu3+ increases with increasing the annealing temperature and the number of coating cycles.     

Encapsulation and photoluminescent property of [Eu(bpy)2]3+ in mesoporous material HMS

The photoluminescence properties of europium (III) ions and its complex with 2,2'-bipyridine, [Eu(bpy)2]3+, encapsulated in the hexagonal mesoporous material HMS are reported. X-ray diffraction spectra, ICP analysis, IR spectra, N2 adsorption measurements, and the photoluminescence spectra were used to characterize the corresponding impregnated samples. All the impregnated HMS samples exhibit the typical photoluminescence properties of Eu3+ when excited with a xenon lamp. These results show that HMS is an efficient host lattice for the photoluminescence of the europium (III) ions bound to an appropriate ligand.     

Preparation and luminescence properties of LaMgAl11O19:Eu3+ phosphor powder

LaMgAl11O19, is a kind of rare earth aluminate with the hexagonal structure, which has been used as a host material for the luminescence of various rare earth and magnet-like ions. LaMgAl11O19:Eu3+ phosphors have been prepared through the one-pot method. X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TG-DTA) and photoluminescence spectra were used to characterize the resulting phosphors. The results of XRD indicated that the phosphors crystallized completely at 1,400 degrees C. In LaMgAl11O19:Eu3+ phosphors, the Eu3+ shows its characteristic red emission at 615 nm (5D0-7F2) upon excitation into 404 nm, with an optimum doping concentration of 15 mol% of La3+ in the host lattices.     

The two-photon excitation of SiO(2)-coated Y(2)O(3):Eu(3+) nanoparticles by a near-infrared femtosecond laser

In order to improve the photoluminescence property of Eu(3+)-doped nanoparticles, Y(2)O(3):Eu(3+) nanoparticles were synthesized using the Pechini-type sol-gel method, then coated with SiO(2) shells by using the St?ber method for different coating times. The SiO(2)-coated nanoparticles were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy and Raman spectroscopy, and their photoluminescence spectra were recorded under 800?nm femtosecond laser excitation. The results indicate that a two-photon simultaneous absorption upconversion luminescence is obtained, and their upconversion luminescence intensities are further enhanced after the surfaces of the nanoparticles are coated with different thickness SiO(2) shells. Compared to the upconversion luminescence intensity of non-coated nanoparticles at 611?nm, the upconversion luminescence intensities of SiO(2)-coated Y(2)O(3):Eu(3+) nanoparticles with coating times of 60, 90 and 120?min were enhanced by 3.30, 3.96 and 4.13 times, respectively. This can be attributed to the contributions of the increased amounts of Eu(3+) ions populated at the (5)D(0) level on the surfaces of the nanoparticles because the cooperative ligand fields between the Y(2)O(3) core and non-crystalline SiO(2) shell interfaces activate the 'dormant' Eu(3+) ions near or on the surfaces of the nanoparticles. From a Judd-Ofelt (J-O) theory analysis, the coated shell structures can improve the radiative quantum efficiencies of Eu(3+)-doped nanoparticles. It is therefore concluded that more intense red upconversion luminescence with high radiative quantum efficiencies can enable the SiO(2)-coated Y(2)O(3):Eu(3+) nanoparticles to have the great potential to be used as a fine resolution phosphor.     

Synthesis and photoluminescence of Y2O3:RE3+ (RE=Eu, Tb, Dy) porous nanotubes templated by carbon nanotubes

Y2O3:RE3+(RE=Eu, Tb, Dy) porous nanotubes were first synthesized using carbon nanotubes as template. The morphology of the coated precursors and porous Y2O3:Eu3+ nanotubes was determined by scanning electron Microscopy (SEM) and transmission electron microscopy (TEM). It was found that the coating of precursors on carbon nanotubes (CNTs) is continuous and the thickness is about 15 nm, after calcinated, the Y2O3:Eu3+ nanotubes are porous with the diameter size in the range of 50-80 nm and the length in micrometer scale. X-ray diffraction (XRD) patterns confirmed that the samples are cubic phase Y2O3 and the photoluminescence studies showed that the porous rare earth ions doped nanotubes possess characteristic emission of Eu3+, Tb3+, and Dy3+. This method may also provide a novel approach to produce other inorganic porous nanotubes used in catalyst and sensors.     

Synthesis and luminescence properties of lanthanide (III)-doped YF3 nanoparticles

Synthesis process and luminescence properties of trivalent lanthanide ions (Ln3+) doped YF3 nanoparticles have been investigated. To synthesis Ln(3+)-doped YF3 nanoparticles, the mixture of (YCl3 x nH2O + LnCl3 x nH2O), and NH4F was hydrothermal treated at 180 degrees C in a Teflon-liner auto-clave or heated at higher temperatures (400 degrees C - 600 degrees C) in a stove. The XRD patterns showed that the Ln(3+)-doped orthorhombic YF3 nanoparticles with no second phase have been prepared. The solid solution Y(1-x)Eu(x)F3 (x = 0 - 0.4) nanoparticles have been synthesized. The luminescence concentration quenching resulted from resonance energy transfer between neighboring Eu3+ ions occurred at higher Eu3+ concentrations (30 mol%). The upconversion luminescence of Er(3+)-Yb3+ codoped YF3 nanoparticles under 980 nm excitation has also been observed. With increase of heated temperature, the size of the Er(3+)-Yb3+ codoped YF3 nanoparticles increased gradually, and upconversion luminescence intensity increased significantly.     

Structure, charge transfer bands and photoluminescence of nanocrystals tetragonal and monoclinic ZrO2:Eu

Eu(3+)-doped tetragonal and monoclinic ZrO2 (called t-ZrO2:Eu and m-ZrO2:Eu, respectively) nanoparticles were prepared using the Pechini sol-gel process. The samples were characterized via X-ray diffraction (XRD) and field-emission-scanning electron microscopy (FE-SEM), and with photoluminescence spectra. The influences of the Eu3+ concentration and the fired temperature on the crystal phase composition of the tetragonal and monoclinic ZrO2:Eu were reported. The typical interesting photoluminescence (PL) properties of the t-ZrO2:Eu and m-ZrO2:Eu nanoparticles were presented. In the t-ZrO2:Eu and m-ZrO2:Eu, the main emission peaks were at 607 and 615 nm, respectively, both of which originated from the 5D0-7F2 transition. The excitation band of the t-ZrO2:Eu powder with a lower Eu3+ doping concentration that was obtained at a low temperature (450 degrees C) consisted of a broad band of 230-500 nm. Both broad excitation bands in the t-ZrO2:Eu and m-ZrO2:Eu were ascribed to the O(2-) - Eu3+ charge transfer (CT) transition. The reason was discussed based on the relationship between the CT energy and its crystal structure. The CT energy of m-ZrO2:Eu is higher than that of t-ZrO2:Eu. A detailed chemical bond analysis was performed to explore the CT energy difference between t-ZrO2: Eu and m-ZrO2:Eu.     

Effect of doping of calcium fluoride nanoparticles on the photoluminescence properties of europium complexes with benzoic acid derivatives as secondary ligands and 2-aminopyridine as primary ligand

The present article reports the synthesis of three Eu(III) complexes [Eu(BA)₃(2-ap)] (1), [Eu(HBA)₃(2-ap)] (2) and [Eu(ABA)₃(2-ap)] (3) (BA = benzoic acid, HBA = 2-hydroxy benzoic acid, ABA = 2-amino benzoic acid and 2-ap = 2-aminopyridine) carried out in ethanol solution. The complexes were further doped with CaF₂ nanoparticles and a change in the photoluminescence properties was observed. The compositions and structural investigation of the complexes were determined by elemental analysis and Fourier transform infrared spectroscopy (FTIR) which suggest the coordination of ligands with the central Eu(III) ion. The optical properties of the complexes were studied by Ultraviolet Visible absorption spectroscopy (UV–Vis) and photoluminescence studies (PL). The relative PL intensity was enhanced in the Eu(III) complexes doped with CaF₂ nanoparticles as compared to the pure Eu(III) complexes, however the increase in intensity varied in the order of ligands ABA > HBA > BA. The photoluminescence lifetime decay curves also revealed the longer lifetime (τ) and higher quantum efficiency (η) for europium complexes with ABA ligands suggesting the efficient energy transfer and better sensitizing ability of the ligand to europium ion. The morphology of the synthesized compounds were studied by Scanning Electron Microscopy (SEM) revealing spherical morphology with agglomeration of the nanoparticles.     

Ln(Ln=Gd3+,Cu+,Sm3+,Dy3+)助激活的Ca8Mg（SiO4）4Cl2∶Eu2+荧光粉的光谱特性和Eu2+的格位计算

采用高温固相法合成了掺杂Ln(Ln=Gd3+,Cu+,Sm3+,Dy3+)作助激活离子的氯硅酸镁钙荧光粉。通过X射线衍射(XRD)对Ca8Mg(SiO4)4Cl2∶Eu2+,Ln进行了表征,结果表明Ln的共掺杂并没有影响基质晶体的面心立方结构。所合成的荧光粉发射峰值位于507nm的绿光区,激发光谱在330~430nm之间均有较强吸收,与紫光InGaN芯片(395nm)相匹配。掺杂Ln作助激活剂增强了荧光粉的发光强度。借助Uitert经验公式计算出Eu2+在Ca8Mg(SiO4)4Cl2基质中占据八配位Ca(Ⅱ)格位。     

Novel molecular precursor of lanthanide complexes with long chain mono cis-butene dicarboxylate to the controlled synthesis of Y2O3:Eu3+ phosphors

Maleic anhydride was modified with long chain alcohols (1-hexadecanol, 1-octadecanol, 1-eicosanol and docosyl) to their corresponding amphiphilic mono-L cis-butene dicarboxylates (L = hexadecyl, octadecyl, eicosyl and docosyl). Subsequently, corresponding amphiphilic lanthanide (Y3+, Eu3+) complexes with these four mono-L cis-butene dicarboxylate ligands [Ln(L')3, Ln = Eu, Y; L' = MAH, MAO, MAE, MAD] were synthesized. Then, under heating at various temperatures (700, 800, 900, 1000, and 1,100 degrees C), twenty kinds of nanosized Y2O3:Eu3+ phosphors were prepared using these four as-derived amphiphilic lanthanide (Y3+, Eu3+) complexes as precursors. All four complexes can form nanosized micelle-like aggregates by special self-assembly. Results show that, under heating at 1,000 degrees C, the four Y2O3:Eu3+ phosphors present more regular dispersion particle-like morphology, and the particle size is in the range of 30-80 nm. They exhibit an especially strong emission at 609 nm, and the luminescence intensity of the sample derived from MAD at 1,000 degrees C is best.     

Y2O2S:0.03Eu,0.03Ti的长余辉特性及Ti向Eu3+的余辉传能机制

采用高温还原法合成了Eu，Ti共激活橙红色Y2O2S长余辉发光材料，并测量了Y2O2S：0．03Eu,0．03Ti磷光体的荧光光谱，余辉分辨和余辉衰减曲线谱．实验结果表明，Y2O2S：0．03Eu,0．03Ti磷光体的发射谱由一系列Eu^3＋离子内部能级跃迁的尖峰组成；余辉分辨谱则不同，由一个主峰位于565nm的宽发射带和一系列波长范围位于500nm以上的窄发射带两种峰形组成，可分别归为Ti离子的宽带余辉发射和三价Eu^3＋的线状余辉发射,分析认为，样品中存在Ti余辉发射向Eu^3＋内部能级间产生选择性的余辉传能机制，从而导致Y2O2S：0．03Ti，0．03Eu磷光体中同时出现两种发光中心离子的余辉分辨谱现象．     

A facile synthesis, in vitro and in vivo MR studies of d-glucuronic acid-coated ultrasmall Ln₂O₃ (Ln = Eu, Gd, Dy, Ho, and Er) nanoparticles as a new potential MRI contrast agent

A facile one-pot synthesis of d-glucuronic acid-coated ultrasmall Ln(2)O(3) (Ln = Eu, Gd, Dy, Ho, and Er) nanoparticles is presented. Their water proton relaxivities were studied to address their possibility as a new potential MRI contrast agent. We focused on the d-glucuronic acid-coated ultrasmall Dy(2)O(3) nanoparticle because it showed the highest r(2) relaxivity among studied nanoparticles. Its performance as a T(2) MRI contrast agent was for the first time proved in vivo through its 3 T T(2) MR images of a mouse, showing that it can be further exploited for the rational design of a new T(2) MRI contrast agent at high MR fields.     

Fabrication and luminescent enhancement of Eu3+-doped Y2O3@YOF core-shell nanocrystals

In this paper, a two-step synthesis method for preparing Eu3+ ion-doped Y2O3@YOF core-shell nanocrystals is introduced. Eu3+ ion-doped Y2O3@YOF core-shell nanocrystals were prepared by combining an autocombustion process with a low temperature solid state reaction. X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), photoluminescence (PL) and fluorescence decay were employed to characterize the prepared samples. The results of XRD, TEM and EDS indicated that the products prepared by this method were not a mixture of Y2O3:Eu3+ and YOF:Eu3+ nanocrystals, but Eu3+ ion-doped Y2O3@YOF core-shell nanocrystals. Compared with Y2O3:Eu3+ nanocrystals, a 20% increment in luminescence intensity was observed in the Eu3+ ion-doped Y2O3@YOF core-shell nanocrystals, thus suggesting that coating with a YOF:Eu3+-shell can efficiently block the nonradiative relaxation channels that are induced by surface defect states.     

聚对苯乙炔/Eu（phen）_2Cl_3杂化材料的合成及光学性能

采用原位脱氯化氢缩合聚合法制备了聚（2-甲氧基-5-辛氧基）对苯乙炔/二元稀土配合物Eu（phen）2Cl3（PMO-COPV/Eu（phen）2Cl3）杂化材料。红外光谱证实了在Eu（phen）2Cl3表面的包覆层为PMOCOPV。紫外-可见吸收光谱表明与PMOCOPV相比,PMOCOPV/Eu（phen）2Cl3的...