Zn2+掺杂诱导Eu3+激活BiOCl层状半导体的反常发光性能研究

采用固相法在500℃下成功制备Zn²⁺掺杂BiOCl:Eu³⁺层状半导体, 并研究了Zn²⁺ (0~20mol%)掺杂对Eu³⁺激活BiOCl层状半导体发光性能的影响。利用X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电镜(SEM)、傅里叶变换红外光谱(FT-IR)、激发-发射光谱、荧光寿命衰减曲线对样品的结构和性能进行表征。研究发现, 随Zn²⁺掺杂浓度增大, BiOCl晶体结构不变, Eu³⁺荧光寿命延长, 但发光强度却出现先减后增的反常现象。综合分析表明这可能与BiOCl特殊的层状结构有关。通过XRD和XPS的表征可以推断: 当Zn²⁺掺杂浓度≤10mol%, Zn²⁺在BiOCl中掺杂方式以晶胞层间隙掺杂为主; 当Zn²⁺掺杂浓度>10mol%后, 掺杂方式逐渐向取代掺杂转变。两种掺杂机制对Eu³⁺荧光寿命的改变以及形成缺陷对基质能量传递效率的影响可能是形成上述反常现象的主要原因。研究结果有助于认识稀土掺杂层状半导体的发光性能及影响规律, 并对Eu³⁺掺杂BiOCl这类新型发光材料的开发设计具有指导意义。     

Copper Extraction from Waste Printed Circuit Boards

The quick development in the electronics industry has allowed an increase in e-waste generation; which cannot be disposed of a traditional way due mainly to the content of hazardous and polluting elements. This has given rise to a social and environmental problem in terms of handling and end disposal. Further, these wastes have become a source of heavy metals, posing challenges for recovering them and development of efficient and environmentally responsible extraction methods. An extraction process to copper extraction from printed circuit boards has been proposed. This method consists on a size reduction, concentration by magnetic and electrostatic separation, leaching of copper in sulfuric acid solution with hydrogen peroxide and oxygen and electrowinning and copper oxychloride precipitation. Concentrates with up to 63% copper and 85% maximum recovery were obtained. Copper extraction over 95% in 100 mL of 2.3 M sulfuric acid solution with 18 mL of hydrogen peroxide during 60 min of process was achieved. Metallic copper with purity over 99% and copper oxychloride as a value-added product also were obtained. This process represents a viable alternative for the recovery of copper from e-waste, contributing to management and end disposal problems, closure of the metals cycle and global sustainable development.     

Electrochemical Immuno-Vascular Solid State Point of Care Testing （POCT）

In this work, it is proposed a POCT and innovative method of immunoassay for the detection of C-reactive protein and IgG, using Amperometry coupled to solid state kit, connected to a micro-flow system with comparable sensitivity to a high sensitivity CRP ELISA （hsCRP） and IgG ELISA, with 1-3 min turnaround time to result. Samples of CRP （0 to 250 ng·mL-1） and IgG or diluted spiked human serum are injected through a solid state polymeric kit, micro-flow sensor channels of a SWCT SPE nano-modified biosensor. Preparing two kits immuno-assays, in the same micro-column, built on oxirane groups of polymeric bead surface, with biological support to CRP and IgG biomarkers recognition, in a real time scheme, at the end of analyte injection the initial rate of change in current intensity I/A was proportional to CRP respectively IgG concentration, with low detection limit （LOD） of 0.1 ng·mL-1. It was revealed that CRP/IgG concentrations in serum that might be expected in both normal and pathological conditions can be detected in a real-time-efficient, multi-immunoassay with solid state detection kit technology with determined CRP/lgG concentrations in close agreement with those determined using a commercially available high sensitivity EL1SA.     

Effect of Impact Milling and Ball Milling on Microstructure of Lead Titanate Powders Synthesized by Solid-State Reaction

Single phase lead titanate （PbTiO3） was prepared by solid-state route using lead （1I） oxide （PbO） and titanium dioxide （TiO2） as precursors. The effects of using impact mill （IM） and ball mill （BM） in solid state reaction have been observed. X-ray diffraction （XRD） pattern was recorded at room temperature and analyzed by employing Rietveld method. X-ray diffraction （XRD） pattern shows that the PbTiO3 particles are tetragonal with tetragonality （c/a） ratio ranging from 1.058 to 1.063 and average crystallite size from 40.8 to 64.2 nm. It is found that the impact mill （IM） can be used to produce pure tetragonal perovskite with a lower tetragonality and average crystallite size.     

v-PrBO3的晶体结构、相变和光学性质

采用高温固相合成法分别在1200和1500℃合成了λ-PrBO₃和ν-PrBO₃样品, 并通过单晶X射线衍射确定了ν-PrBO3的晶体结构。结果表明该结构为三斜晶系, 空间群为P1, 晶胞参数为a = 0.6302 (4) nm, b = 0.6521 (4) nm, c = 0.6525 (4) nm,α = 94.312(7)°,β = 107.335(7)°,γ = 106.455(7)°, V = 0.2417(2) nm³, Z = 4。同时研究了从λ-PrBO₃到ν-PrBO₃的相变过程, 并从漫反射光谱得出λ-PrBO3和?-PrBO3的光学带隙均为4.96 eV。在X射线和紫外激发下,均未观测到λ-PrBO3和?-PrBO3样品在紫外可见波长范围内的Pr³⁺特征发光。     

Er3+掺杂弛豫铁电材料PMNT的单晶生长与性能表征

按照0.71Pb(Mg_1/3Nb_2/3)O₃-0.26PbTiO₃-0.03Pb(Er_1/2Nb_1/2)O₃化学式所示组分比例, 采用分步高温固相反应合成出Er³⁺掺杂PMNT多晶, 通过熔体坩埚下降法生长出尺寸φ25 mm×100 mm的Er³⁺掺杂PMNT晶体, Er³⁺离子以三元固溶体组元方式被掺杂进入钙钛矿相铁电体晶格; 测试了Er³⁺掺杂PMNT晶片的介电、压电与铁电性能以及上转换发光性能。结果表明, Er³⁺掺杂PMNT晶体呈现跟三方相纯PMNT晶体相近的介电、压电与铁电性能; 在980 nm激发光作用下, 该掺杂晶体呈现出Er³⁺离子特有的较强上转换荧光发射, 并且极化后掺杂晶体的上转换发光强度得到增强。     

Thermoluminescence behaviour of KCL(1-x)Br(x):Pb2+ exposed to gamma radiation

The thermoluminescence (TL) behaviour of solid solutions of lead doped KCl(1-x)Br(x) (X = 0.02, 0.35, 0.50, 0.65, 0.85, 1) mixed crystals exposed to gamma radiation at different doses from 60Co is reported. The TL glow curves of KCl(1-x)Br(x):Pb2+ crystal exposed in the range of 0-140 Gy is strongly dependent on composition X. The maximum temperature of the main TL glow peak was found to shift towards lower temperatures as composition X increased and a significant enhancement of the TL efficiency in KCl(1-x)Br(x):Pb2+ was found for X = 0.50 which is attributed to an increase in the vacancy concentration of the mixed halides at middle composition. The participation of the F-centre in the TL phenomenon particularly related to the main TL glow peak observed in mixed samples was also confirmed.     

Nanorods of white light emitting Sr2SiO4:Eu2+: microemulsion-based synthesis,EPR, photoluminescence,and thermoluminescence studies

White light emitting Sr₂SiO₄:Eu²⁺ nanoparticles were prepared using reverse micellar route using Tergitol as a surfactant. The systems were characterised by X-ray diffraction, scanning electron microscopy (SEM), photoluminescence, thermoluminescence (TL), and electron paramagnetic resonance (EPR) spectroscopy. SEM shows the formation of silicate nanorods. Two emission bands of bluish-green at 490 nm (S(I)) and of orange-red at 605 nm (S(II)) were observed. The two emission bands are assigned to the 4f–5d transition of Eu²⁺ ions in two different cation sites in α′-Sr₂SiO₄ orthorhombic lattices. Gamma-irradiated Sr₂SiO₄:Eu showed the presence of three TL glow peaks at 437, 487 K and weak peak at 540 K; however, no glow was observed in the undoped sample. Reduction of Eu³⁺ to Eu²⁺ is confirmed by EPR spectroscopy.     

Growth of n-type and p-type ZnSe thin films using an electrochemical technique for applications in large area optoelectronic devices

ZnSe layers have been grown by a low temperature (65 °C) electrochemical deposition technique in an aqueous medium. The resulting thin films have been characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive analysis by X-rays (EDAX), glow discharge optical emission spectroscopy (GDOES) and X-ray fluorescence (XRF) for bulk material properties. A photo-electrochemical (PEC) cell and an optical absorption method have been used for determination of the electrical and optical properties of the thin films. XRD patterns indicate the growth of ZnSe layers with (1 1 1) as the preferred orientation. The XPS spectra are similar to those of commercially available ZnSe and the EDAX, GDOES and XRF also indicate the presence of Zn and Se in the layers. PEC studies show p-type semiconducting properties for the as deposited layers and n-type ZnSe can be produced by appropriate doping. Optical absorption is maximum around 460 nm indicating a band gap of 2.7 eV. Annealing at 200 °C for 15 mins improves both the crystallinity of the layers and the photoresponse of the electrolyte/ZnSe liquid/solid Schottky junction. © 1998 Chapman & Hall     

Thermoluminescent properties of Mn-doped YAP synthesized by the solution combustion method

The work describes results of Mn-doped YAlO₃ (YAP) nanocrystalline materials synthesized by the solution combustion method using urea as a fuel. The materials were characterized by X-ray powder diffraction, scanning electron microscopy and luminescence techniques. The combustion synthesis method with codoping with Hf⁴⁺ ions allows to obtain highly efficient YAP:Mn²⁺ phosphor with negligible emission from Mn⁴⁺ ions that can be applicable for thermoluminescent dosimetry of ionizing radiation. Namely, the phosphor has a single dominating thermal glow peak at about 200 °C with the green emission near 530 nm related to Mn²⁺(Y) ions.     

Ca10K（PO4）7:Eu3+红色荧光粉的制备及其发光性质

高温固相法合成了Ca10-xK(PO4)7:xEu3+(x=0.02,0.04,0.06,0.08,0.10,0.12,0.14和0.16)的红色荧光粉。X射线衍射表明,样品具有标准的Ca10K(PO4)7六角晶体结构,且无第二相存在。在393nm的波长激发下,样品获得由Eu3+的4f-4f跃迁产生红光发射,其中以613nm附近的5 D0→7F2电偶极跃迁发射为最强。通过调节Eu3+的掺杂浓度,获得了色坐标与商业化Y2O2S:Eu3+荧光粉十分接近的接近纯色的红色荧光粉。Ca10K(PO4)7:Eu3+是一种可望应用于紫外激发的白光LED的红色荧光粉。     

Effect of concentration on the photoluminescence properties of Sm3+ and Dy3+: cadmium lithium boro tellurite glasses

Rare-earth (Sm3+ or Dy3+) ions doped cadmium lithium boro tellurite glasses have been prepared by melt quenching method for their spectral studies. From X-ray diffraction (XRD) patterns the glass amorphous nature has been confirmed. Vis-NIR absorption, excitation and emission spectra of these glasses have been analyzed systematically and also rare earth ion concentration is optimised Sm3+: CLiBT glasses have shown strong orange-reddish emission at 598 nm (4G5/2-->6H7/2) with an excitation wavelength lambda(exci) = 401 nm and Dy3+: CLiBT glasses have shown strong yellow emission at 574 nm (6F9/2-->6H13/2) with lambda(exci) = 451 nm.     

Zn3-xMnxTeO6的晶体结构与吸收光谱和磁性研究

本工作主要研究Mn ²⁺离子掺杂的类刚玉系氧化物Zn₃TeO₆(0<x≤2.0)的晶体结构与光学性质和磁性的变化。Zn_3-xMn_xTeO₆粉末样品通过固相反应合成。Mn掺杂量的相图表明, x<1.0时保持单斜(C2/c)结构, 1.0≤x≤1.6为单斜(C2/c)和三方六面体混合相(R-3), x≥1.8时完全转变为R-3相, 且x=2.0时形成ZnMn₂TeO₆, Te-O和Mn/Zn-O键长增大, 八面体发生更大畸变。X射线粉末衍射结构精修也表明R-3相中Zn/MnO₆为畸变八面体。随着Mn ²⁺掺杂含量的增加, Zn_3-xMn_xTeO₆系列化合物不仅结构发生变化, 其颜色也由浅变深。紫外吸收光谱中随着掺杂浓度的增加, 400~550 nm处的吸收增强, 样品的光学带隙也由3.25 eV (x=0.1)逐渐减小到2.08 eV (x=2.0), 分析表明, 可见区吸收的增强是源于MnO₆八面体中Zn/MnO₆八面体中Mn ²⁺离子的d-d跃迁, 导致样品由浅黄色逐渐变为暗黄色。 磁性测试表明, 固溶体的反铁磁转变温度随着Mn ²⁺掺杂量的提高而逐渐增加, 且掺入的Mn ²⁺离子以高自旋态 存在。     

A high-power low-pressure iodine lamp pumped by glow discharge

We present the working characteristics of a high-power UV-VUV electric-discharge lamp filled with a working mixture of helium and iodine vapor (He-I₂) at a low pressure (0.1–1.5 kPa) and pumped by a dc glow discharge at a power of 15–200 W. The power of the total output UV radiation and the main emission peak at λ = 206.2 nm were studied as dependent on the electric power supplied to the glow discharge and on the partial pressure of helium in the He-I₂ mixture. The emission characteristics of the glow discharge plasma were studied in the spectral range from 200 to 350 nm. In this range, the lamp is operating predominantly on a resonance emission line of excited iodine atoms (λ = 206.2 nm, FWHM = 0.10–0.12 nm) and on a system of electronic-vibrational bands of excited iodine molecules with the main peak at λ = 342 nm. The contribution of the resonance emission due to excited iodine atoms to the total UV emission from the glow discharge plasma does not exceed 50%. The optimum partial pressure of helium is within 400–800 Pa. The total UV radiation power of the lamp operating in the optimum regime reaches 25 W at an efficiency of η ≤15%.     

Scintillation and dosimeter properties of <Superscript>6</Superscript>LiF/CaF<Subscript>2</Subscript>:Eu eutectic composites

We investigated scintillation and dosimeter properties of ⁶LiF/CaF₂ eutectic composites doped with different concentrations of Eu (0.005, 0.02, 0.1, 0.3, and 1.0). In the photoluminescence (PL) and scintillation spectra, an emission peak at 430 nm due to the 5d–4f transitions of Eu²⁺ was observed. The intensity of PL and scintillation for ⁶LiF/CaF₂:0.005%Eu was the highest among the samples tested. In thermally stimulated luminescence (TSL), several glow peaks of ⁶LiF/CaF₂:0.005%Eu were observed after X-ray irradiation of 1000 mGy. The TSL response exhibited a linear response against X-ray dose over a dose range of 1–10,000 mGy. In optically stimulated luminescence (OSL), an emission peak was observed at 430 nm during a stimulation by 630 nm light after X-ray irradiation of 1000 mGy. The OSL intensity was the highest for ⁶LiF/CaF₂:0.005%Eu among all the samples investigated.     

Wear resistance of TiN coatings implanted with Al and N ions

Titanium nitride (TiN) coatings were prepared on HS 6-5-2 high-speed steel cutting inserts and next implanted either with Al ions (fluence 2×10¹⁷ ions/cm²) or with Al and N ions (fluence (1+1)×10¹⁷ ions/cm²) on the rake face. Microhardness and friction coefficient of the implanted surfaces were examined. A noticeable increase of microhardness in Al implanted inserts has been observed.The elemental composition and structural properties of the surface layer were examined by glow discharge optical emission spectroscopy (GDOES) and gliding angle X-ray diffraction (XRD).The tests of turning of 40 H constructional steel with the cutting inserts have shown an improvement in the implanted inserts, especially marked in those implanted with Al+N.     

Eu2+在多铝酸钠体系中的发光

应用高温固相法合成了Na的多铝酸盐,并研究了Eu^2＋在体系中的发光性能．结果表明,Na_1＋xMgAl_11－xO₁₇体系在整个组成范围内保持Na的β－Al₂O₃结构不变,而对于Na_1．67－2xBa_xAl1_0．33O₁₇体系,在x＝0．30附近体系结构发生转变,x＜0．30,体系形成Na的外β－Al2O3结构的固溶体,x＞0．30,体系形成Ba的β－Al₂O₃结构的有序体;与体系组成和结构的变化相对应,Eu^2＋的发射能量和发光强度产生相应的变化,在Na的β－Al₂O₃中Eu^2＋存在高、低能两种发射中心;通过系列化研究,获得了新的组成的、具有β－Al₂O₃结构的荧光体Na_0．67Ba_0．50Mg_0．67Al_10．33O₁₇：Eu^2＋,在较低的掺杂浓度（0．05mol）下可以产生较强的发光．     

Hydrothermal synthesis and photoluminescence of Eu(2-x)Sm(x)Sn2O7 (x = 0-2.0) nanophosphors

Eu(2-x)Sm(x)Sn2O7 (x = 0, 0.1, 0.5, 1.0, 1.5, and 2.0) solid solutions were successfully synthesized by a simple, mild hydrothermal process. The crystal structure, particle size, and chemical composition of the solid solutions were characterized by X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. X-ray diffraction patterns and transmission electron microscopy images reveal that all the products were cubic pyrochlore-type Eu(2-x)Sm(x)Sn2O7 nanocrystals with the diameter of approximately 20 nm. Due to efficient energy transfer from Sm3+ to Eu3+, the Eu(2-x)Sm(x)Sn2O7 (x = 0.1, 0.5, 1.0, and 1.5) nanocrystals exhibited strong 5D0 --> 7F1 photoluminescence emission of Eu3+. The dominant 5D0 --> 7F1 transition revealed good monochromaticity and low distortion of the Eu(2-x)Sm(x)Sn2O7 nanophosphors.     

Luminescence Study of LiY<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>Eu<Subscript>x</Subscript>(MoO<Subscript>4</Subscript>)<Subscript>2</Subscript>

The luminescence spectra of LiY_{1 − x} Eu_x(MoO₄)₂ (x = 0.0005, 0.001, 0.01, 0.05, 0.1, 0.5, 1) scheelite solid solutions are measured under laser excitation at 337.1 nm. The effect of Eu³⁺ concentration on the luminescence behavior of the solid solutions is examined. The highest integrated emission intensity is offered by LiY_0.5Eu_0.5(MoO₄)₂. Eu³⁺ substitution for Y³⁺ has no effect on the symmetry of the emission centers involved. Eu³⁺ is shown to occupy only one site in the structure of the solid solutions. X-ray diffraction and luminescence data indicate that all of the solid solutions have an undistorted scheelite structure.__________Translated from Neorganicheskie Materialy, Vol. 41, No. 7, 2005, pp. 871–875.Original Russian Text Copyright © 2005 by Zaushitsyn, Mikhailin, Romanenko, Khaikina, Basovich, Morozov, Lazoryak.     

Effect of heat treatment on photoluminescence behavior of BaMgAl10O17:Eu phosphors

The blue phosphor of BaMgAl₁₀O₁₇:Eu²⁺ (BAM) powders were prepared by solid-state reaction. The thermal degradation of BAM phosphor significantly reduces the intensity of the blue emission. BAM is reduced by an amount of 50% after heating at around 800 °C for 1 h. Photoluminescence (PL) excitation and emission spectra showed that the blue emission of 450 nm peak decreased with increasing annealing temperature. The ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂ transition of Eu³⁺ were observed at 590 and 615 nm emission lines over 1100 °C. Electron paramagnetic resonance (EPR) spectrum also detected two signals of Eu²⁺, corresponding to g=3.7156(9) for 88 mT, and g=2.9507(9) for 133 mT. X-ray absorption near edge structure (XANES) spectrum decreased the intensity of Eu²⁺ for 6977 eV with increasing annealing temperature, while high-energy peak of Eu³⁺ for 6984 eV was increased. The combined use of X-ray and neutron data by the Rietveld refinement appears to support that the secondary phase of EuMgAl₁₁O₁₉ magnetoplumbite structure in BAM may be formed by heat treatment.