Structure and luminescence properties of Sm^(3+) doped Y_2MoO_6 phosphor under near ultraviolet light excitation

A series of Sm3＋ doped Y2MoO6 were prepared through high temperature solid state reaction technique. Their phase structures, morphologies and luminescence properties were investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and photoluminescence spectrometry. The most intense absorption of Y2MoO6 host occurred at 367 nm. Energy transfer from host lattice to Sm3＋ ions could be observed, and the schematic diagram of energy transfer was constructed, The critical energy transfer dis- tance and energy transfer mechanism between Sm3＋ ions were discussed in detail. Considering the high color purity and appropriate emission intensity, Sm3＋ doped Y2MoO6 could be a promising phosphor under near ultraviolet light excitation.

Applications and recent advances of rare earth in solid oxide fuel cells

Solid oxide fuel cells(SOFCs)are an all-solid energy conversion device from the chemical energy of fuels to electric energy at intermediate and high temperatures.Up to now,massive efforts have been made in developing different components of solid oxide fuel cells,including electrolyte,anode,cathode and interconnect materials.Rare earth elements play an indispensable role in different components of SOFCs which have been extensively studied in the recent decades.In this review,we concentrate upon the rare earth application and recent advances in SOFCs and related materials.Materials structure involves perovskites,Ruddlesden-Popper,fluorite,spinel,pyrochlore,apatite and so on.Moreover,the effects of rare earth based oxides as matrix or dopants in different components are also discussed.Structures and properties of the materials are related to the element type,valence,coordination and ion radius.This article will provide a comprehensive research direction towards SOFCs components for their composition,structural design and mechanisms research.

Characterization and photoluminescence of Lu_2O_3-Eu^(3+) nano-phosphor prepared by modified solution combustion method

Nanoscale Lu2O3：Eu3＋ phosphor was prepared by a modified solution combustion method using urea and acrylamide monomer.The particle sizes and photoluminescent properties of nano-phosphor were closely related to the molar ratio of urea-to-RE nitrates and acrylamide monomer-to-RE nitrates.The as-prepared samples with the sizes of 9.6-11.6 nm were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscopy and energy dispersive spectrometer.Lu2O3：Eu3＋ nano-phosphor that depicted high photoluminescence in the size around 10 nm was reported.Compared with the sample prepared by solid state reaction,the photoluminescence of sample was increased sufficiently to be 45.1%.The emission spectra of the samples presented the typical emission from 5D0 level to 7FJ（J=0,1,2,3,4） level of the Eu3＋ ion.

Blue light-induced rare-earth free phosphors for the highly sensitive and selective imaging of latent fingerprints based on enhanced hydrophobic interaction

The demand for in-situ detection of latent fingerprints(LFPs)in ways of high sensitivity,high selectivity,high contrast,low cost and user-friendly is still urgent.To overcome this challenge,a moisture-stable,red-emitting fluoride phosphor K_(3)AlF_(6):Mn^(4+)(KAF:Mn^(4+))with an organic hydrophobic skin was prepared.The phosphor has a uniform and superfine morphology with excellent luminescence properties.More importantly,this non-ultraviolet(UV)or non-near infrared(NIR)induced phosphor was proved to be an ideal fluorescent label for LFP imaging,which is both friendly for touch DNA analysis and compatible to forensic light sources.The well-defined ridge details with little background interference on various surfaces were presented by the oleic acid(OA)modified KAF:Mn^(4+)(KAF:Mn^(4+)-OA)phosphor in few seconds using the powder dusting method.To confirm the high selectivity of KAF:Mn^(4+)-OA for LFP imaging,an efficient quantitative evaluation method is proposed with the aid of ImageJ&Origin software.Due to the superiority of the Mn^(4+)-doped fluoride for the rapid imaging of LFPs in terms of lowcost,high compatibility and good availability,it is expected to be a promising candidate for forensic science as well as fluorescence imaging in other fields instead of rare earth luminescent materials.

Synthesis and luminescence properties of BaWO_4:Pr^(3+) microcrystal

BaWO4：Pr^3＋ （hereafter BWO：Pr） microcrystals were prepared via a hydrothermal route, and characterized by X-ray diffraction （XRD）, scanning electron microscope （SEM）, photoluminescence excitation and emission spectra. The as-prepared products with different morphologies of egg-shape rod, olive-like, and quasi-sphere were obtained by the addition of the surfactants and chelating agents. The emis-sion spectra of BWO：Pr microcrystals showed the strong red emission （642 nm） assigned to the Pr^3＋ ions of 3P0→3F2 transition with blue ex-citation （484.6 nm, 3H4→3P0）.

Experimental study and thermodynamic calculation of Lu2O3-SiO2 binary system

As a binary system of BaO-Lu_2O_3-SiO_2 ternary system, Lu_2O_3-SiO_2 system was optimized and calculated by CALPHAD approach based on available phase diagram and relevant thermodynamic data of RE_2O_3-SiO_2（RE=Lu,Yb,Y） binary systems as well as our experimental data of Lu_2O_3-SiO_2 system obtained by quenching experiment. The Gibbs free energy of high temperature solution was described by an ionic two-sublattice model as（Lu^（3＋））P（O^（2-）, SiO_2~0）Q. The calculated phase diagram below 1873 K was in good agreement with experimental data at 1573, 1773 and 1873 K. The calculated Gibbs energies of two intermediate phases Lu_2SiO_5 and Lu_2Si_2O_7, the activity of Lu_2O_3 and SiO_2 and specific heat capacities of intermediate phases agreed well with experimental results of Y_2O_3-SiO_2 system. This tentative study will offer help for the research of single-phase phosphor and related metallurgical slags, refractories, high-temperature superconductivity material systems.

Photoluminescence enhancement of YAG:Ce^(3+) phosphor prepared by co-precipitation-rheological phase method

YAG：Ce3＋ phosphor was prepared by a novel co-precipitation-rheological phase method.The resulting YAG：Ce3＋ phosphor was characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM） and photoluminescent emission spectra.By using acetic acid as solvent,YAG：Ce3＋ powder with small particle size（≤2 μm） was obtained at a relatively lower sintering temperature of 1400 oC.With the content of acetic acid increasing,small particles dissolved and disappeared,but larger particles grew up and changed its shape from spherical to partially rectangular.Meanwhile,the emission intensity of the sample prepared by co-precipitation-rheological phase method was about 43% higher than that of the sample prepared by co-precipitation method.It was assumed that the significant improvement of luminescence was mainly because the rheological phase presented a better diffusion environment,and therefore,a better homogeneity of activators of Ce3＋.

Energy transfer and cross-relaxation induced multicolor upconversion emissions in Er^3+/Tm^3+/Yb^3+ doped double perovskite La2ZnTiO6 phosphors

Investigation on the bright and stable upconversion(UC)phosphors with multicolor emissions is fundamental and significant for the frontier applications of display and tempe rature probe.He re,dive rse emitting colors with blue,cyan and yellowish green,which are caused by the energy transfer and crossrelaxation processes,are obtained by altering Er^3+,Tm^3+and Yb^3+concentrations in Er3+singly,Er^3+-Tm^3+-Yb^3+co-and tri-doped double perovskite La2ZnTiO6(LZT)phosphors synthesized by a simple solid-state reaction.In addition,excellent infrared emission at 801 nm located at"first biological windo w"is collected in Tm^3+-Yb^3+co-doped phosphors.Meanwhile,the temperature sensing properties based on the thermally coupled levels((^2H11/2)/(^4S3/2))of Er3+ions were analyzed from 298 to 573 K of LZT:0.15 Er^3+/0.10 Yb^3+phosphor,demonstrating that the maximal sensitivity value is about56×10^-4 K^-1 at 448 K.All these results imply that this kind of UC material has potential applications in display,bioimaging and optical device.

Study on hydrogen adsorption on WO_(3)(001) surface by density functional theory calculation

Hydrogen reduction of tungsten oxide is currently the most widely used technology to produce metal tungsten for its simplicity and pollution-free nature.The computer simulation is a powerful tool for exploring the mechanism of hydrogen reduction of tungsten oxide from a microscopic view.The density functional theory(DFT) is applied to investigate the adsorption characteristic of hydrogen molecule on the surface and inside the lattice of WO_(3).The adsorption energy of hydrogen on the WO_(3)(001) surface is 66.56 kJ.mol^(-1) which is larger than the adsorption energy of hydrogen molecule inside the lattice of WO3 which indicates that once the hydrogen diffuses inside the lattice,it is easier to adsorb on the O atom to break W-O bond.And The diffusion process of a hydrogen molecule from the WO-terminated WO_(3)(001) surface to the inside of the WO_(3) lattice and hydrogen molecule adsorption inside the lattice was investigated.The activation energy of hydrogen molecule diffusion from the surface down to the first interstitial and diffusion from the first interstitial down to the second interstitial is 195.41 and 172.81 kJ·mol^(-1),respectively.The controlling step of hydrogen reduction of tungsten oxide may be the hydrogen molecule diffusion inside the oxides lattice through the interstitial.

Single-phase full-color Ba_3Lu_2(SiO_4)_3:Eu^(2+) phosphor for white-light emitting diodes

we developed a new silicate-based full-color phosphor Ba3Lu2（SiO4）3：Eu2＋ through solid state reaction.The host crystal structure was isostructural with Ca3Y2（SiO4）3 instead of garnet-type.The phosphor absorbed near-ultraviolet light from 250 to 400 nm,which was very suitable for a color converter of white LED that used UV-LED as the primary light source.The photoluminescence peak wavelength of Ba3Lu2（SiO4）3：Eu2＋ was about 461 nm and a shoulder peak was around 522 nm,which resulted from the 5d-4f transition of the Eu2＋.The optimum concentration of Eu2＋ was 3.45 mol.% of Ba2＋ content in Ba3Lu2（SiO4）3 host.It is a promising candidate for application in white LED as a white light converter.

FeNiS_(2)/reduced graphene oxide electrocatalysis with reconstruction to generate FeNi oxo/hydroxide as a highly-efficient water oxidation electrocatalyst

It is critical to developing electrocatalysts with highly active and cost-effective for oxygen evolution to resolve environmental pollution and energy issues,in which FeNi-based nanomaterials hold a great promise.Herein,(Fe_(0.33 )Ni_(0.67))S_(2) and(Fe_(0.33 )Ni_(0.67))S_(2)/reduced graphene oxide(rGO)-x%(x=10,20) composites,which exhibited highly efficient oxygen evolution reaction(OER)electrocatalytic activity under alkaline conditions,were synthesized via a hydrothermal approach and following thermal treatment with sulfur powders.Benefiting from the integrated structure of(Fe_(0.33 )Ni_(0.67))S_(2)and support of conductive graphene backbones,(Fe_(0.33 )Ni_(0.67))S_(2)/rGO-20%electrocatalyst showed the best OER activity with an overpotential of 172 mV at 10 mA·cm^(-2)and Tafel slopes of 45 mV·decade^(-1).The composition,phase,and surface structure of the catalyst were characterized before and after OER reaction.The results indicated that crystal phase of the catalyst was reconstructed to the amorphous crystalline features after OER,with oxidation of iron-nickel sulfide and appearance of Ni-Fe oxo/hydroxide species,which may play a crucial role in the high OER performance as the catalytic-active.Moreover,in a two-electrode system towards overall water splitting with(Fe_(0.33 )Ni_(0.67))S_(2)/rGO-20%/NF and Pt/C/NF as the anode and cathode,respectively,the catalysts exhibited excellent catalytic performance with the voltage of only 1.42 V at 10 mA·cm^(-2).