Eu3+掺杂羟基磷灰石的制备及其发光性质

采用沉淀法制备了Eu3+掺杂的羟基磷灰石(hydroxyapatite,HAP),用荧光光谱、X射线衍射和扫描电镜等测试手段对所得样品进行了表征.结果表明:Eu3+的发光特性以及其占据HAP晶格中Ca(Ⅱ)和Ca(Ⅰ)位点的比例随Eu3+掺杂浓度和烧结温度改变而变化;随着Eu3+掺杂量的增加,Eu3+掺杂HAP的红光发...     

Effect of Al3+ on the spectroscopic properties of Eu2+- and Tb3+-Doped high silica glass

In this study, Eu²⁺/Al³⁺-, Eu²⁺/Tb³⁺-, and Eu²⁺/Tb³⁺/Al³⁺-doped high silica glasses were prepared, and the effect of Al³⁺ on the spectroscopic properties of Eu²⁺ and Tb³⁺ and the energy transfer of Eu²⁺→Tb³⁺ was investigated. The results revealed that the addition of Al³⁺ increased the luminescent intensity of the Eu²⁺-doped glass by approximately 400 times. An obvious Eu²⁺→Tb³⁺ energy transfer occurred in the Eu²⁺/Tb³⁺-doped high silica glass, whose transfer efficiency can reached 66.9%. However, the efficiency continuously decreased as the Al³⁺ concentration increased, and eventually, it dropped to 7.2%. These phenomena can be explained by the following: Al³⁺ not only disperses Eu²⁺ but also changes the field strength and symmetry of its neighboring environment, thus increasing its emission intensity. Moreover, Al³⁺ destroys the strong dipole–dipole interactions between Eu²⁺ and Tb³⁺ in high silica glass due to its dispersive ability, which inhibits the energy transfer of Eu²⁺→Tb³⁺. This indicates that a small amount of Al³⁺ can significantly modify the neighboring environment of Eu²⁺ and change its light-emitting characteristics, potentially yielding efficient blue and green phosphors excited by near-ultraviolet light for use in white light-emitting diodes.     

掺铒高增益磷酸盐激光玻璃的研究进展

掺铒磷酸盐激光玻璃具有受激发射截面大、增益系数高和量子效率高等优点,目前已成为通信领域中广泛应用的一种新型光纤放大器材料.本文主要介绍其性能特点、最新研究进展和应用以及工艺改善方法.     

稀土Eu~(3+)与牛血清白蛋白配合物合成及其分子光谱表征

研究了稀土 Eu3 +与牛血清白蛋白 ( BSA)的固体配合物合成方法 ,产物经傅里叶红外光谱分析表明 :Eu3 + 与牛血清白蛋白羧基的氧和胺基或酰胺基的氮形成强烈配位的配合物。在模拟生理条件下研究了 Eu3 + 与 BSA的结合性质。荧光光谱表明 :Eu3 + 与 BSA形成 2 .75∶ 1的配合物 ,表观配位常数为 lg K=1 2 .2 6     

Structure and Upconversion Luminescence Properties of Pr3+-Doped Y2SiO5 Phosphor

Silicon - Ultraviolet-C light has significant application prospects in the fields of disinfection, air purification, etc. Herein, an effective UVC upconversion phosphor Y2SiO5:Pr3+ was successfully...     

Preparation,characterization and photoluminescence properties of SiO2 and SiO2:Eu3+ submicron rods

SiO₂ and Eu³⁺-doped SiO₂ submicron rods were conveniently fabricated via a sol–gel process at room temperature. In this process, citric acid served as a unique structural modifier through hydrolysis of TEOS at alkaline condition to obtain the silica submicron rods. The morphology of the products was sensitive to the conditions, such as stirring, gelation time and the dropping speed of NH₄OH. By sampling the products at different reaction times, we discussed the formation and growing mechanism of SiO₂:Eu³⁺ submicron rods in detail. The weak interactions between ammonium citrate crystals and silica species may be the reasons of the rods formation. The obtained silica submicron rods were 5–6 μm in length and 650–750 nm in width and there was no obvious change after doping. Under UV light excitation, the undoped silica submicron rods exhibited blue emission, which may be associated with defect centers in the structures of the products. The Eu³⁺-doped silica submicron rods exhibited red emission, which was due to the 4f→4f transition of Eu³⁺. The effect of different doping concentrations of Eu³⁺ ions on the luminescence was investigated. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR), Thermo-gravimetry Analysis (TGA), Scanning electron microscope (SEM), Transmission electron microscope (TEM), Energy-dispersive spectroscopy (EDS) and Photoluminescence spectrum.     

Li2SrSiO4:Eu2+,Tb3+中Eu2+和Tb3+的发光特性和能量传递

用高温固相法在N2/H2=95/5(v/v)还原气氛下合成了Li2SrSiO4:Eu2+,Tb3+荧光粉发光材料,通过荧光光谱研究其发光特性,并从理论上探讨了Eu2+与Tb3+之间的能量转移类型。结果表明:该发光材料主发射峰值550nm,与Eu2+在4f7-4f65d1产生跃迁有关;通过掺杂,共存于Li2SrSiO4基质中的Tb3+通过电多级相互作用将能量传递给Eu2+;在500~650nm范围内对Eu2+具有很强的敏化作用,使其在主发射峰550nm的发射强度显著增强;当名义化学组成为Li2Sr0.995SiO4:0.005Eu2+,0.010Tb3+时,发光强度为最佳。     

Ca2Na2La6(SiO4)4(PO4)2O: Eu2+/Eu3+: A visual dual-emitting fluorescent ratiometric temperature sensor

A novel apatite-based UV-excited dual-emitting Ca₂Na₂La₆(SiO₄)₄(PO₄)₂O: Eu²⁺/Eu³⁺ phosphor (CNL: Eu²⁺/Eu³⁺) was designed and successfully synthesized by a solid-state reaction. Compared with previous reports on this family of materials, a structural study based on DFT calculation exhibited a new consequence that the monovalent ions in this system are more inclined to occupy the seven-coordinate cationic sites rather than the nine-coordinate sites. This result was confirmed by the structural refinement and high-resolution transmission electron microscopy (HRTEM) data. Due to the coexistence of Eu²⁺ and Eu³⁺ dopants in the material, under 345 or 392 nm excitation, CNL: 0.02Eu²⁺/Eu³⁺ exhibited a green Eu²⁺ emission band (528 nm) and red Eu³⁺ emission peaks (around 618 nm). The application potential of CNL:0.02Eu²⁺/Eu³⁺ in luminescent thermometry was studied by exploiting the temperature sensitivity of the fluorescent intensity ratio (green/red) at different temperatures. It was found that, under 345 nm excitation, the fluorescent intensity ratio of CNL: 0.02Eu²⁺/Eu³⁺ displayed linear correlation over the temperature range of 298 to 473 K with a high sensitivity of 2.82%K⁻¹. Additionally, the emission color of the CNL: 0.02Eu²⁺/Eu³⁺ sample under UV lamp (254 and 365 nm) excitation showed an obvious change (from green to red) as the temperature increased from 298 to 473 K (from green to red). These results indicated that CNL: Eu²⁺/Eu³⁺ can serve as an excellent visual luminescent ratiometric thermometer. Furthermore, this work provides a novel reference for developing high-performance luminescence temperature-sensing materials.     

低温固相合成掺铜磷酸锌钠及其数据挖掘的研究

以ZnSO4·7H2O,Na3PO4·12H2O为原料,硫酸铜为掺杂剂,以PEG-400为表面活性剂,经低热固相反应合成得到掺杂铜的磷酸锌钠纳米晶.用产物XRD图谱数据计算得到的结晶度作为试验的考察指标,试验中应用了均匀设计试验法及数据挖掘技术,在数据挖掘成果的指导下进行了试验.试验结果表明,用最优工艺条件合成得到的产物为52 nm的掺铜NaZnPO4·H2O,结晶度为98.80%,与数据挖掘得到的最佳结果相吻合.     

Synthesis and photoluminescence properties of Eu2+/Eu3+ or Ce3+/Eu3+ co-doped Sr5(BO3)3F compounds

The synthesis and photo-luminescence properties of Eu²⁺/Eu³⁺ or Ce³⁺/Eu³⁺ co-doped Sr₅(BO₃)₃F compounds are reported. Using the Sr₅(BO₃)₃F as the host, through the solid state reaction under the reductive atmosphere, Eu²⁺/Eu³⁺ and Ce³⁺/Eu³⁺co-doped samples were prepared. These compounds exhibit good photo-luminescence properties. Under the excitation of 376 nm, an unusual red orange emission coming from the Eu²⁺ ions can be obtained in Eu ions doped Sr₅(BO₃)₃F, which exhibits a broadband emission in the range of 450–800 nm with the peak at around 600 nm. At the same time, the characteristic f-f excitation and emission of Eu³⁺ can improve and adjust the Eu²⁺ emission in Eu³⁺/Eu²⁺ codoped Sr₅(BO₃)₃F. In addition, the adjustable luminescence properties from blue to white of Sr₅(BO₃)₃F:Ce³⁺, Eu³⁺ are investigated. The energy transfer behavior from Ce³⁺ to Eu³⁺ was confirmed. In the spectra of the co-doped samples, we can hardly observe the characteristic peak of Eu²⁺, because Ce⁴⁺ can oxidize Eu²⁺ to Eu³⁺, and Ce⁴⁺ itself is reduced to Ce³⁺. The CIE coordinates from (0.2758, 0.2420) to (0.3857, 0.3015) show Sr₅(BO₃)₃F:3%Ce³⁺, x%Eu³⁺ (x = 1,3,5,7,9) are in the white light emission region. All results demonstrate that the Sr₅(BO₃)₃F:Eu³⁺/Eu²⁺ and Sr₅(BO₃)₃F:Ce³⁺/Eu³⁺ phosphors have good application prospects for LED plant growth and white LED, respectively. The bond energy method was used to explain the reason why the Eu²⁺/Eu³⁺ ion instead of only Eu²⁺ and Ce³⁺/Eu³⁺ instead of Ce³⁺/Eu³⁺/Eu²⁺ can exist in the host Sr₅(BO₃)₃F. The theoretical analysis agree well with the experimental result.     

Eu2+掺杂的发光材料的制备及荧光性能

采用溶胶-凝胶法制备了系列Sr_2MgSiO_5:Eu~(2+)发光材料,并采用X射线衍射仪(XRD)、荧光光谱(PL)等测试方法对样品的物相结构和发光特性进行了表征及测试。研究结果表明:Sr_2MgSiO_5:Eu~(2+)发光材料中,加入少量Eu~(2+)离子后没有明显改变Sr_2MgSiO_5晶体结构,提高晶化温度有利于Sr_2MgSiO_5晶相的生成。当晶化温度为1150℃时,晶化时间为2 h,光谱强度最大Ba2MgSiO5:Eu~(2+)发光强度最佳。本文合成Sr_2MgSiO_5:Eu~(2+)发光材料可以应用到白光LED的技术中。     

Eu~(3+)掺杂的红色荧光粉制备及荧光性能研究

利用溶胶凝胶法制备了Eu3+掺杂的Y2O3荧光粉。考察了Y2O3:Eu3+的制备条件,进行了物相表征,研究了Y2O3:Eu3+的荧光性能。结果表明,在612 nm波长监测下,Y1.98O3:Eu3+0.02的激发光谱为300~550 nm,最大激发峰值位于466 nm,归属于Eu3+的7F0→5D2的跃迁。在466 nm波长激发下,Y2O3:Eu3+的发射光谱为550~700 nm,最大发射峰值位于612 nm,归属于Eu3+的5D0→7F2的跃迁主峰。Eu3+的掺杂量为x=0.02,p H=1时Y2O3:Eu3+荧光粉可以得到最强的红光荧光粉。     

La3+掺杂CdS/TiO2复合膜的制备及性能表征

采用溶胶-凝胶和旋涂工艺在普通玻璃表面制备La3+掺杂CdS/TiO2薄膜,采用XRD和UV-VIS等测试手段研究了CdS复合量、La3+掺杂量、焙烧温度和镀膜层数对La3+掺杂CdS/TiO2薄膜的结构、光学性能及光催化性能的影响.结果表明,经过合理掺杂和复合技术制备的TiO2纳米复合膜具有比单独掺杂或复合薄膜更好的光催化能力.当CdS的复合量40%(CdS/TiO2摩尔比0.4)、La3+掺杂量0.5%(La3+/Ti4+摩尔比0.005)、焙烧温度600℃、膜层数为6时,薄膜在可见光区域具有良好的透过率,在太阳光下4 h对0.4 mg·L-1甲基蓝溶液的降解率可达到60%以上.     

Effects of Eu content on the luminescent properties of Y2O3:Eu3+ aerogels and Y(OH)3/Y2O3:Eu3+@SiO2 glassy aerogels

This article describes the morphological, structural, and luminescent properties of Y₂O₃:Eu³⁺ aerogels and Y(OH)₃/Y₂O₃:Eu³⁺@SiO₂ glassy aerogels synthesized by the sol-gel method with Eu concentrations from 2.5 mol% to 30 mol%. XRD measurements indicated that both the aerogels and glassy aerogels had a monoclinic phase, but the crystallinity in the glassy aerogels was lower due to the presence of SiO₂. SEM images reveal that a three-dimensional porous network was formed in the aerogels due to the interconnection of coalesced Y₂O₃:Eu³⁺ nanoparticles. The 3D porous network was also observed in the glassy aerogels, coated with a silica shell. In both the aerogels and glassy aerogels, the size of the agglomerates decreased as the europium concentration increased. This, in turn, increased the average size of the macropores that formed their 3D network. Furthermore, the luminescent properties of the aerogels and glassy aerogels were studied under UV excitation, and it was observed that their red emission intensity increased continuously as the Eu³⁺ concentration increased. The luminescence of the aerogels was on average 50% higher than that of the glassy aerogels. Hence, our results indicate that porous and luminescent aerogels with and without silica are adequate for applications in sensing and catalysis.     

SiO_2-Al_2O_3-CaO-MgO高强度玻璃纤维掺杂TiO_2的结构性能研究

采用高温熔融的方法制备了不同TiO_2掺杂量的Si O_2-Al_2O_3-Ca O-Mg O高强玻璃纤维,借助FT-IR、XRD和SEM等研究了玻璃的结构和性能。结果表明:随着TiO_2掺杂量的增加,玻璃的密度先快速上升后变缓,玻璃的摩尔体积则先快速下降后变缓;玻璃的介电常数出现极大值,介电损耗出现极小值;玻璃纤维的拉伸强度和断裂伸长率均呈现先增大后减小的趋势。XRD和SEM表明掺杂TiO_2不会使玻璃析晶倾向增加,不影响玻璃纤维的拉丝工艺。     

Synthesis,structure, luminescence and photocatalytic properties of CaTiO(SiO4):Eu3+

Titanite CaTiO(SiO₄):Eu³⁺ were synthesized by a solvothermal-calcination method and an improved high-temperature solid-state synthesis method. Their structure, luminescence properties and photocatalytic propoties were comparatively studied in detail. It was found that CaTiO(SiO₄):Eu³⁺ synthesized by the two methods belong to two different types of crystalline and each of them has its own advantages and disadvantages. Titanite synthesized by solvothermal-calcination method has rough and porous surface morphology, larger BET, and smaller crystallite size, which result in a weaker luminescence intensity than the one synthesized by high-temperature solid-state method. But in the experiment of photocatalysis, all these disadvantages are turned into advantages. In addition, the high temperature process also increases the symmetry of Eu³⁺ occupation and leads to many surface traps, which result in a less red color and a shorter fluorescence life than solvothermal synthesized titanite. We hope that this comparative study will extend the applications and research ideas of titanite.     

某磷尾矿制备超细二氧化硅的工艺研究

对云南某磷尾矿进行了物相和成分分析,针对其SiO2含量较高的特点,以碳酸钠为熔剂提取磷尾矿中的SiO2,再以反应制得的硅酸钠母液为原料通过化学沉淀法制备了超细SiO2,考察了SiO2提取条件和超细SiO2制备条件。确定最优的SiO2提取条件为:煅烧温度850℃、投料比1.6∶1、煅烧时间10min;超细SiO2制备条件为:终点pH=7、盐酸浓度1mol·L-1、表面活性剂CTAB添加量0.94%。用XRF、XRD、BET、激光粒度仪、FTIR对产品进行了表征,所得超细SiO2是非晶态物质,D50=120nm、比表面积652.1866m2·g-1、纯度99.05%。     

SiO2-MTES-CTAB-Al2O3纳米复合薄膜的制备及性能研究

以异丙醇铝和正硅酸乙酯为主要原料,采用溶胶-凝胶分步水解法,通过引入有机硅烷甲基三乙氧基硅烷和表面活性剂十六烷基三甲基溴化氨,并用乙二醇甲醚替换铝溶胶中水作为对比,制备了SiO2-MTES-CTAB-Al2O3纳米复合薄膜.通过FT-IR、可见光透射光谱分析、薄膜表面接触角测量及机械性能测试,研究了化学组成、煅烧温度和有无乙二醇甲醚替换对复合薄膜的影响.结果表明:不用乙二醇甲醚替换效果更好,经400 ℃热处理后不同配比复合薄膜在可见光区的透光率均大于85%,且不影响复合薄膜的疏水性,由于铝氧化物颗粒、十六烷基三甲基溴化氨和甲基三乙氧基硅烷的存在,所制备的纳米复合薄膜的硬度及耐摩擦性能均有较大提高,改善了力学性能,从而获得了具有良好的疏水性、透过率及硬质的SiO2-MTES-CTAB-Al2O3纳米复合薄膜.     

Fluorescence properties with red-shift of Eu2+ emission in novel phosphor-silicate apatite Sr3LaNa(PO4)2SiO4 phosphors

A series of Eu²⁺-activated novel phosphor-silicate apatite Sr₃LaNa(PO₄)₂SiO₄ phosphors were synthesized by solid-state reaction. The X-ray diffraction (XRD) and Rietveld refinement, diffuse reflectance spectra, luminescent spectra, decay curves and thermal quenching properties were applied to characterize the obtained phosphors. The XRD result revealed that all the samples possessed only a single phase with hexagonal structure and the doping of Eu²⁺ ions were successfully incorporated into the crystal lattice. The reflectance spectra showed an obvious red-shift of the wavelength from 400 to 700 nm with increasing Eu²⁺ ion concentration. The three different crystallographic sites of Eu²⁺ ions had been confirmed by their lifetimes. All the samples exhibited broad absorption bands from 200 to 450 nm, revealing the phosphor-silicate phosphor interesting for application in the near-UV used phosphor-converted LED chips. These results suggested that the Eu²⁺-activated phosphor-silicate Sr₃LaNa(PO₄)₂SiO₄ phosphors have the potential for near-UV pumped white-light-emitting diodes (w-LEDs).     

溶胶-凝胶法合成纳米Ca3SiO5:Eu2+荧光粉

用溶胶-凝胶法在弱还原气氛下合成了纳米级Ca3SiO5:Eu2 绿色荧光粉.研究了Eu2 浓度的含量对发光强度的影响,表明在Ca3SiO3:Eu2 中添加Eu2 的最佳含量为0.005 mol.x射线衍射分析表明:在1000～1200 ℃合成的Ca3SiO5:0.005 Eu2 样品为单相Ca3SiO5晶体.根据Scherrer公式计算样品的平均晶粒尺寸为30 nm左右,与扫描电镜分析结果基本相符.样品的发射光谱与激发光谱都为宽带谱,其中发射光谱是峰值为505 nm的不对称宽带谱,而激发光谱是主峰为374 nm的连续光谱.