High-temperature High-pressure Hydrothermal Synthesis of Dy3＋-doped YNbO4 Single Crystal and Its Luminescence Properties

Single crystal Dy3＋ doped YNbO4phosphors were prepared via a high-temperature high-pressure hydrothermal procedure. Under excitation at 270 nm, the Dy3＋-doped YNbO4 phosphor shows bright white emission, which is composed of two strong bands at 492 and 576 nm corresponding to the characteristic 4F9/2→6H15/2 and aF9/2→6H13/2 transitions of Dy3＋, respectively. The dominant band was observed at 352 nm, which corresponds to the 6H15/2→6p7/2 transition of Dy3＋. Nearly white light was achieved at 2ex 270, 310 and 388 nm and the CIE（International Commission on Illumination） values were （0.3135, 0.3421）, （0.3088, 0.3380） and （0.3146, 0.3296）, respectively.     

Synthesis and Fluorescence Properties of Eu^2＋-Doped KMgF3 Nanoparticles

Introduction Nanomaterialsusuallyshowsomenoveloptical,electronic,magneticandchemicalpropertiessignifi cantlydifferentfromthoseofthebulkmaterialsbecause oftheirextremelysmallsize,largespecificsurfaceare asandpeculiarquantumsize.Thepotentialoftheirap plicat…     

Vacuum Ultraviolet Excited Photoluminescence Properties of Y2O2S：Eu^3＋,Bi^3＋ Phosphor

As an Hg-free lamp using phosphor, the Bi^3＋ and EH^3＋ co-doped Y2O2S phosphors were prepared and their luminescence properties under vacuum ultraviolet（VUV） excitation were investigated. The VUV photoluminescent intensity of Y2O2S：Eu^3＋ was weak, however, considerably stronger red emission at 626 nm with good color purity was observed in Y2O2S：Eu^3＋,Bi^3＋ systems. Investigation on the photoluminescence reveals that the strong VUV luminescence of Y2O2S：Eu^3＋,Bi^3＋ at 147 nm is mainly because the Bi^3＋ acts as a medium and effectively performs the energy transfer process： Y^3＋-O^2-→Bi^3＋→Eu^3＋, while the intense emission band at 172 nm is attributed to the absorption of the characteristic ^1So-^1P1 transition of Bi^3＋ and the direct energy transfer from Bi^3＋ to Eu^3＋. The Y2O2S：Eu^3＋,Bi^3＋ shows excellent VUV optical properties compared with the commercial （Y,Gd）BO3：Eu^3＋. Thus, the Y2O2S：Eu^3＋,Bi^3＋ can be a potential red VUV-excited candidate applied in Hg-free lamps for backlight of liquid crystal display.     

Vacuum Ultraviolet Excited Photoluminescence Properties of Y2O2S：Eu^3＋,Bi^3＋ Phosphor

As an Hg-free lamp using phosphor, the Bi3+ and Eu3+ co-doped Y2O2S phosphors were prepared and their luminescence properties under vacuum ultraviolet(VUV) excitation were investigated. The VUV photoluminescent intensity of Y2O2S:Eu3+ was weak, however, considerably stronger red emission at 626 nm with good color purity was observed in Y2O2S:Eu3+,Bi3+ systems. Investigation on the photoluminescence reveals that the strong VUV luminescence of Y2O2S:Eu3+,Bi3+ at 147 nm is mainly because the Bi3+ acts as a med...     

Study on the Synthesis of La（3）-doped Nano-TiO_2 and Photocatalytic Degradation of Methyl Orange

In this paper,La(3)-doped Nano-TiO2(La(3)-TiO2) was synthesized via hydrothermal process.Structure and optical properties of the synthesized samples were characterized via XRD,FT-IR,DRS,etc.The results showed that the phase transformation of TiO2 from anatase to rutile was effectively prevented by La(3)-doping,which improved the thermal stability of anatase,and also suppressed particle aggregation and grain growth of TiO2.The formation of Ti-O-La bond promoted UV absorption intensity of TiO2,and provoked red shift of absorbed light.And the spectra response range of TiO2 was extended significantly to visible light by La(3)-doping,then photocatalytic performance was improved effectively.Compared with pure nano-TiO2,the performance of La(3)-TiO2 which photocatalyticly degraded methyl orange was increased significantly.     

Synthesis,Crystal Structure,and Photoluminescence Properties of One Novel D-π-D Type a-Cyanostilbene Derivative

Researches on a-cyanostilbene derivatives demonstrated them to be promising AIE or AIEE structural molecules and potential photoelectric materials. One novel a-cyanostilbene derivative, namely （E）-2-（4-butoxyphenyl）-3-（4-（diethylamino）phenyl）acrylonitrile （BPDPA）, has been designed, synthesized and characterized. The crystalline structure of BPDPA has been studied in detail. The single-crystal X-ray diffraction revealed BPDPA crystallizes in triclinic space group Pi, with a = 12.860（5）, b = 13.327（5）, c = 15.016（5）А, a = 72.650（5）, β = 66.969（5）, Y = 62.897（5）°, Mr = 696.95, V= 2085.6（13） A3, Z = 2, Dc = 1.110 g/cm-3, p = 0.068 mm1, F（000） = 752, Rint = 0.0264, R（I〉 2σ（/）） = 0.0649, wR（l〉 2σ（/） = 0.1724, R（all data） = 0.1321, wR （all data） = 0.2158, completeness to theta = 25.00 is 99.4% and GOF = 1.067. Like most reported a-cyanostilbene derivatives, BPDPA possesses a somewhat twisted molecular structure. UV-Vis and FL measurements showed an obviously bathochromic effect of BPDPA with increasing the polarity of the solvents.     

Synthesis, Characterization and Thermochemistry of 2MgO：B2O3：1.5H2O

Introduction　　 2MgO·B2 O3(Mg2 B2 O5)and 2MgO·B2 O3·H2 Omightbepreparedaswhiskermaterials .12MgO·B2 O3·H2 OnamedszaibelyiteisamagnesiumboratemineralwithastructuralformulaofMg2 [B2 O4 (OH) 2 ].2 Itisdifficulttosynthesizethiscompoundinthelaboratory .Recently ,weobtainedasimilarcompound 2MgO·B2 O3·1 5H2 Owhenwetriedtopreparewhiskerof 2MgO·B2 O3·H2 Obythephasetransformationof 2MgO·2B2 O3·MgCl2 ·14H2 OinH3BO3solutionunderhydrothermalcondition .Itishope fultopreparewh…     

Hydrothermal Synthesis of PEG-capped ZnS：Mn2＋ Quantum Dots Nanocomposites

Water-soluble Mn2＋-doped ZnS nanocrystals surface capped with polyethylene glycol（expressed as PEG-ZnS：Mn2＋） were synthesized in aqueous solution with PEG as surface modifier without ligand exchange.The particles were obtained via chemical precipitation method at 100 ℃ with an average diameter of 3 nm and a zinc blende structure.The PEG modified on the surface of PEG-ZnS：Mn2＋ nanocrystals rendered the nanocrystals water soluble and biocompatible.And the PEG-ZnS：Mn2＋ nanocrystals have the potential application in molecular assembly and biological fluorescence analysis.The effects of the Mn2＋ concentration,stabilizer concentration,and synthesis time on the photoluminescence（PL） intensity of ZnS：Mn2＋ QDs were also investigated.     

Hydrothermal Synthesis ofAgLnMo2O8（Ln=La, Nd, Eu） Hierarchical Structures： Growth Mechanism and Photoluminescence Property

<正>Uniform AgLnMo_2O_8(Ln=La,Nd,Eu) hierarchical architectures were firstly synthesized via a facile hydrothermal method.These three dimensional architectures were assembled from primary micro-rods and the average diameter was about 5μm.According to the time-depend experiments,a possible growth mechanism was proposed to be a self-assembling process followed by an Ostwald ripening step.The concentrations of precursor and pH value were also found to have great influences on the final morphologies of the products.In addition,the photoluminescence properties of the products were investigated.     

Synthesis,Structure and Photoluminescence of a Binuclear Zinc（Ⅱ） Coordination Polymer Based on 2-Carboxycinnamic Acid and Dipyrido [3,2-a： 2＇,3 ＇-c]-phenazine

A binuclear zinc（Ⅱ） complex with 2-carboxycinnamic acid （2-ccm） and dipyrido- [3,2-a：2＇,3＇-c]phenazine （DPPZ）, {[Zn2（2-ccm）2（DPPZ）2]·2H2O}n, was synthesized and characterized by elemental analysis, IR, single-crystal X-ray diffraction, thermal gravimetry and fluo- rescent emission. It crystallizes in monoclinic, space group P21/c with a = 13.409（4）, b = 25.530（7）, c = 13.952（4） A, β = 99.554（3）°, V= 4710（2） A3, Z= 4, C56H36N8O10Zn2, Mr= 1111.67, Dc = 1.568 g/cm3, μ（MoKα） = 1.093 mm^-1, F（000） = 2272, R = 0.0422 and wR = 0.0895. In the crystal, the basic unit of 1 is a binuclear Zn2 entity which is linked by 2-ccm ligand to form a 1D double chain along the a axis. The O-H...O hydrogen bonding and π-π interactions lead to a 3D supramolecular motif. In addition, thermal and luminescent properties of complex 1 have also been investigated.     

静电纺丝法制备Mn2O3纳米纤维及其磁性研究

采用溶胶-凝胶过程和静电纺丝技术相结合方法, 以聚丙烯腈和醋酸锰为前驱物, 制得了PAN/Mn(CH₃COO)₂复合纳米纤维. 将该复合纤维高温煅烧, 获得了Mn₂O₃纳米纤维. 采用扫描电镜(SEM)、红外光谱(FTIR)、差热-热重(TG-DTA)和X射线衍射(XRD)分析等对样品进行了表征. 结果表明, Mn₂O₃纳米纤维为规则的一维结构, 直径分布均匀, 具有铁磁性-反铁磁性-顺磁性相互转化的特性.     

Transferring CdTe Nanoparticles from Liquid Phase to Polyvinylpyrrolidone Nanofibers by Electrospinning and Detecting Its Photoluminescence Property

The major aim of this work was to synthesize thio-stabilized CdTe nanoparticles(NPs) in an aqueous solution,which was then enwrapped with cetyltrimethylammonium bromide(CTAB),and finally transferred to the polyvinylpyrrolidone(PVP) matrix by electrospinning,The PVP nanofibers containing CdTe NPs were characterized by scanning electron microscopy(SEM) and transmission electron microscopy(TEM),to observe the morphology of the nanofibers and the distribution of CdTe NPs,The selective area electronic diffraction(SAED) pattern verified that CdTe NPs were cubic lattice,The photoluminescence(PL) spectrum indicated that CdTe NPs existed in an optical style in PVP nanofibers,Moreover,X-ray photoelectron spectra(XPS) revealed that thiol-stabilized CdTe NPs were enwrapped by CTAB,and PVP acted as a dispersant in the process of electrospinning.     

Synthesis and Photoluminescence Properties of Uniform Y2O3:Eu3+ Hollow Spheres with Tunable Shell Thickness

Y2O3:Eu3+ hollow spheres were successfully prepared with melamine formaldehyde(MF) spheres as template. The MF spheres played a significant role in directing the formation of the hollow shells which are composed of numerous primary nanoparticles. Furthermore, the shell thickness of these hollow spheres could be readily tailored by adjusting the dosage of MF template. Based on the photoluminescence(PL) investigation, the red emission intensities(613 nm) of these Y2O3:Eu3+ hollow spheres are greatly influenced by their shell thickness and it was found that hollow spheres with thin shell thickness and intact hollow structures permit a better PL performance.     

A Low‐Temperature Synthesis Route for CaAlSiN3 Doped with Eu2+

A new low‐temperature synthesis route of the strongly red‐emitting Eu²⁺ activated nitride phosphor CaAlSiN₃ is presented. The fluorides CaSiF₆ and AlF₃ were used as a source of metal ions and Li₃N as a nitrogen source. A KCN/LiCl flux system was employed to lower the temperature of the reaction from 1100 to 750 °C. The course of the reaction was studied by differential thermal analysis, and the product of the reaction was inspected by X‐ray powder diffraction and luminescence measurements of CaAlSiN₃:Eu.     

Sr2Si5N8:Eu2+荧光粉的制备与发光性能

以α-Si3N4,SrCO3,Eu2O3为原料,采用碳热还原氮化法制备了Sr2Si5N8:Eu2+荧光粉.研究了材料的结构与光谱特性,分析了影响材料发光性能的工艺因素.结果表明,石墨粉含量和助熔剂的用量对Sr2Si5N8相的形成和发光性能有重要影响.当nc/nSr=1.5,助熔剂用量为4wt%时,合成样品的主晶相为正交晶系Sr2Si5N8,在400～550 nm可见光激发下,可发射峰值波长位于 609nm荧光.激发带的位置与Eu2+离子浓度无关,为400～550 nm之间的宽带激发;但发射强度随Eu2+离子浓度的增加而增加.Eu2+离子浓度达到5mol%时发射强度达最大值,在Eu2+离子浓度为2mol%～5mol%之间,观察到发射峰的红移现象.     

Transferring CdTe Nanoparticles from Liquid Phase to Polyvinylpyrrolidone Nanofibers by Electrospinning and Detecting Its Photoluminesccnce Property

The major aim of this work was to synthesize thio-stabilized CdTe nanoparticles（NPs） in an aqueous solution, which was then enwrapped with cetyltrimethylammonium bromide（CTAB）, and finally transferred to the polyvinylpyrrolidone（PVP） matrix by electrospinning. The PVP nanofibers containing CdTe NPs were characterized by scanning electron microscopy（SEM） and transmission electron microscopy（TEM）, to observe the morphology of the nanofibers and the distribution of CdTe NPs. The selective area electronic diffraction（SAED） pattern verified that CdTe NPs were cubic lattice. The photoluminescence（PL） spectrum indicated that CdTe NPs existed in an optical style in PVP nanofibers. Moreover, X-ray photoelectron spectra（XPS） revealed that thiol-stabilized CdTe NPs were enwrapped by CTAB, and PVP acted as a dispersant in the process of electrospinning.     

Sr3SiO5:Eu2+荧光粉的微波合成及性能研究

0 引 言 白光LED是一种具有广阔前景的节能照明灯具,被誉为人类的第四代照明用灯具.白光LED实现主要有两种方案,其中在蓝光LED芯片上涂覆黄色荧光粉,蓝光芯片发出的蓝光与荧光粉发出的黄光复合而获得白光,受到人们的重点关注[1-5].     

核壳型Gd2O3:Eu3+@Y2O3纳米发光材料的制备与发光性能

采用均相沉淀法制备了均匀球形的Gd2O3:Eu3+@Y2O3核壳结构纳米发光材料.XRD结果表明经过800℃焙烧后样品为立方晶系的Gd2O3,并且晶体发育良好,包覆Y2O3之后Gd2O3的衍射峰位置无明显变化,但随着包覆厚度的增加,出现了立方晶系Y2O3的衍射峰.FTIR谱图观测到了Gd-O,Y-O伸缩振动吸收峰,随着包覆厚度的减少吸收峰增强,认为当包覆层的厚度适当时,颗粒表面的悬空键(断键)变少,Gd(Eu,Y)-O键增多所致.SEM表明包覆前后样品为均匀分散的球形结构.XPS分析进一步证明了表面包覆上了Y2O3.荧光光谱表明:纳米Gd2O3:Eu3+表面包覆不同厚度的基质Y2O3后,均观测到Eu3+离子的特征红光发射,当包覆厚度R=4:1时的发光强度比未包覆的Gd2O3:Eu3+增强,认为核-壳型样品降低了纳米Gd2O3:Eu3+的表面效应给发光强度带来的负面影响.     

纳米SrAl2O4:Eu2+,Dy3+长余辉发光材料的制备与性能

采用水热-均匀共沉淀法制备了纳米SrAl2O4:Eu2+,Dy3+长余辉发光材料.通过XRD、TEM、荧光光谱、热释光谱对其结构和性能进行分析.XRD结果表明所制备的SrAl2O4:Eu2+Dy3+纳米发光材料为单相,属单斜晶系.TEM测试表明纳米SrAl2O4:Eu2+,Dy3+发光材料为规则的球状粒子,粒径为50～80 nm,且分散性良好.激发和发射光谱测试表明,样品的激发光谱是峰值在356 nm 的连续宽带谱,发射光谱是峰值位于512 nm的宽带谱,与SrAl2O4:Eu2+,Dy3+粗晶材料相比,激发和发射光谱都出现了"蓝移"现象.样品的热释光峰值位于358 K,适合于产生长余辉.     

静电纺丝法制备NiO纳米纤维及其表征

纳米级NiO因具有优良的催化和热敏等性能而被广泛用于催化剂^[1]、电池电极^[2,3]、光电转化材料^[4～6]、电化学电容器^[7～8]等诸多方面.迄今,已成功地制备出N iO的纳米颗粒^[9]、纳米线^[10]及纳米薄膜^[11],但是对于具有准一维结构的NiO纳米纤维的制备及性能研究尚未见报道.