Irradiation-induced reduction and luminescence properties of Sm doped in BaBPO5

Usually, Sm²⁺ ions could be reduced by heating the materials in reducing atmospheres. Exposure to ionizing radiations is also known to cause Sm³⁺→Sm²⁺ conversion. In this work, BaBPO₅ doped with the samarium ion was prepared by high temperature solid-state reaction. Sm²⁺ ions were obtained by two different reduction methods, i.e., heating in H₂ reduced atmosphere and X-ray irradiation. The measurements of X-ray diffraction (XRD), and scanning electron microscope (SEM) were investigated. It is found that the conversion of Sm³⁺→Sm²⁺ is very efficient in BaBPO₅ hosts after X-ray irradiation. Sm²⁺ ions under these two reduction methods exhibit different characteristics that were studied by measurements of luminescence and decay. The results showed that the luminescence properties of Sm²⁺ ions in BaBPO₅ were highly dependent on the sample preparation conditions.     

A novel Sr3Y(PO4)3-based white light-emitting phosphor

The Sr₃Y(PO₄)₃:0.05Sm³⁺, Sr₃Y(PO₄)₃:0.005Tb³⁺, and Sr₃Y(PO₄)₃:0.005Tb³⁺, 0.05Sm³⁺ phosphors were synthesized using a conventional solid-state reaction technique at high temperature and their photoluminescence properties under ultraviolet (UV) excitation were studied. We observed the UV sensitization of Sm³⁺ emission (565, 600, and 648 nm) by Tb³⁺ in Sr₃Y(PO₄)₃:0.005Tb³⁺, 0.05Sm³⁺, that leads to a white light emission with the CIE coordinate (0.367, 0.312) of Sr₃Y(PO₄)₃:0.005Tb³⁺, 0.05Sm³⁺ phosphor under UV excitation. The emission is a result of partial energy transfer from Tb³⁺ to Sm³⁺, which is discussed in detail in terms of the corresponding excitation and emission spectra.     

Sol-Gel Processing of Sm2+-Doped Glass and Its Spectral Hole Burning at Room Temperature

The sol-gel process was applied to the preparation of Sm²⁺ ion-doped silicate glasses, which show persistent spectral hole burning at room temperature. The gels synthesized by the hydrolysis of metal alkoxides and SmCl₃·6H₂O were heated in air at 500°C, were then reacted with H₂ gas to form the Sm²⁺ ion. The Al₂O₃−SiO₂2 glasses are appropriate to reduce the Sm³⁺ ion with H₂ gas and show intense photoluminescence of Sm²⁺ ion. Persistent spectra hole burning was observed in the excitation spectrum for the⁷F₀→⁵D₀ transition of the Sm²⁺ ion by the irradiation of DCM dye laser. The hole width and depth were ∼16 cm⁻¹ and ∼10% of the total intensity, respectively, at 20°C.     

Luminescence properties of Dy3+ or/and Sm3+ doped LiLa(WO4)2 phosphors and energy transfer from Dy3+ to Sm3+

The Dy³⁺ or/and Sm³⁺ doped LiLa(WO₄)₂ phosphors are synthesized by a facile solid state reaction method. The phase and luminescence properties of the phosphors are investigated. The powder X-ray diffraction (XRD) results show that the phosphor has a tetragonal phase crystal structure. The quenching concentration of single doped Dy³⁺ and Sm³⁺ in the LiLa(WO₄)₂ are determined to be 6% and 3%, respectively. Under the excitation of 404 nm, warm white light is obtained in the co-doped phosphors. With the concentration of Sm³⁺ increasing, the correlated color temperature (CCT) gradually decreases from 3090 to 2453 K. Two kinds of energy transfer may exist at the same time. The overlap between the emission spectrum of Dy³⁺ and the excitation spectrum of Sm³⁺ reveals that the energy of Dy³⁺ can transfer to Sm³⁺ via radiation. Another way of energy transfer, that is non-radiative energy transfer, is attributed to the excited state of Dy³⁺ (⁴F_9/2) slightly higher than that of Sm³⁺ (⁴I_19/2). The calculation results show that non-radiative energy transfer process from Dy³⁺ to Sm³⁺ ions is predominated by quadrupole–quadrupole interaction.     

Luminescent properties and energy transfer process of Sm3+-Eu3+ co-doped MY2(MoO4)4 (M=Ca,Sr and Ba) red-emitting phosphors

MY₂(MoO₄)₄:Sm³⁺ and MY₂(MoO₄)₄:xSm³⁺,yEu³⁺ (M=Ca, Sr and Ba) phosphors were successfully prepared using solid-state reaction route, and their luminescent properties and energy transfer process from Sm³⁺ to Eu³⁺ were systematically investigated. The results indicate that MY₂(MoO₄)₄:Sm³⁺ phosphors can be effectively excited by 407 nm near UV light originating from the ⁶H_5/2 → ⁴F_7/2 transition of Sm³⁺, and exhibit a satisfactory red emission at 646 nm attributed to the ⁴G_5/2 → ⁶H_9/2 transition of Sm³⁺, in which the emission intensity of SrY₂(MoO₄)₄:Sm³⁺ is the strongest among the MY₂(MoO₄)₄:Sm³⁺ (M=Ca, Sr and Ba) phosphors. For Eu³⁺ co-doped MY₂(MoO₄)₄:Sm³⁺ samples, with increasing Eu³⁺ doping content, the main emission peaks of Sm³⁺ (approximately 646 nm) are decreased, but the emission peaks and intensity of Eu³⁺ are increased while the maximum intensity of luminescence at the Eu³⁺ concentration 0.9. The introduction of Eu³⁺ in the MY₂(MoO₄)₄:Sm³⁺ phosphors can remarkably generate a strong emission line at 616 nm, originating from the ⁵D₀→⁷F₂ transition of Eu³⁺ and Sm³⁺ (⁴G_5/2) → Eu³⁺ (⁵D₀) effective energy transfer process. The energy transfer mechanism from Sm³⁺ to Eu³⁺ was discussed in detail.     

CaWO4:xEu3+,ySm3+,zLi+红色荧光粉的制备及光学性能

采用微波固相法制备了CaWO₄：xEu³⁺,ySm³⁺,zLi⁺红色荧光粉。测量样品的XRD图、激发谱、发射谱及发光衰减曲线,研究并分析了Eu³⁺、Sm³⁺、Li⁺的掺杂浓度,对样品微结构、光致发光特性、能量传递及能级寿命的影响。结果表明,Eu³⁺、Sm³⁺、Li⁺掺杂并未引起合成粉体改变晶相,仍为CaWO₄单一四方晶系结构。Eu³⁺、Sm³⁺共掺样品中,Sm³⁺掺杂为3%时,Sm³⁺对Eu³⁺的能量传递最有效。Li⁺掺杂起到了助熔剂和敏化剂的作用,使样品发光更强。在394 nm激发下,与CaWO₄：3%Eu³⁺样品比较,3%Eu³⁺、3%Sm³⁺共掺CaWO₄及3%Eu³⁺、3%Sm³⁺、1%Li⁺共掺CaWO₄样品的发光分别增强2倍及2.4倍。同一激发波长下,单掺Eu³⁺样品寿命最短,Sm³⁺、Eu³⁺共掺样品随Sm³⁺浓度增加,寿命先减小后增加,且掺杂了Li⁺的样品比不掺Li⁺的样品⁵D₀能级寿命有所增加。     

Microcalorimetric Studies on Influence of Sm^3＋, Dy^3＋ on Growth and Sporulation of Bacillus thuringiensis

By using an LKB-2277 Bioactivity Monitor and cycle-flow method, the thermogenic curves of aerobic growth for Bacillus thuringiensis cry Ⅱ strain at 28 ℃ have been obtained. The metabolic thermogenic curves of Bt cry Ⅱ contain two distinct parts: the first part reflects the changes of bacterial growth phase and the second part corresponds to sporulation phase. From these thermogenic curves in the absence or presence of Sm^3 , Dy^3 ions, the thermokinetic parameters such as the growth rate constants k. the interval time τ1, the maximum power PMAX1 and heat-output QLOG for log phase, the maximum power PMAX2 and heat-output QSTAT for stationary phase, the heat-output QSPOR for sporulation phase and total heat effects QT were calculated. Sm^3 and Dy^3 ions have promoting action on the growth of Bt cryⅡ in their lower concentration range, on the other hand, they have inhibitory action on the sporulation of Bt in their higher concentration range, It has also been found that the effects of Sm^3 and Dy^3 ions on Bt during the sporulation phase were far greater than those during the bacterial growth phase. It was concluded that the application of Bt for controlling insecticide could not be affected by the presence of the rare-earth elements in the environmental ecosystem.     

荧光纳米材料YPO4∶Sm3+@YPO4@聚乙二醇的构筑及其荧光性能

为了改善稀土磷酸盐的疏水性和荧光性能,利用水热和微波的方法构筑了双层荧光纳米材料YPO₄∶Sm³⁺@YPO₄@PEG (PEG为聚乙二醇)。首先通过调控YPO₄∶Sm³⁺与YPO₄的物质的量之比制备不同壳厚的核壳结构纳米发光材料YPO₄∶Sm³⁺@YPO₄,优选能够增强主体荧光性能的最佳物质的量之比。然后选用PEG进行包覆,得到YPO₄∶Sm³⁺@YPO₄@PEG。利用X射线衍射、扫描电子显微镜、透射电子显微镜、傅里叶变换红外光谱和荧光光谱对产物的结构、形貌和荧光性能进行了表征。结果表明：包覆前后的纳米荧光粉都具有单一的四方晶系(YPO₄)结构,呈纳米球型,半径60~100 nm,包覆层的厚度10~20 nm。双层核壳结构的YPO₄∶Sm³⁺@YPO₄@PEG的荧光强度比纳米荧光粉YPO₄∶Sm³⁺增强了6倍多。可见该双层荧光纳米材料不仅具有亲水性和生物相容性,也增强了YPO₄∶Sm³⁺的荧光强度。     

Spectroscopic investigation of La7Ta3W4O30:Sm3+ orange-red phosphor for white LEDs

The novel orange-red light emitting La₇Ta₃W₄O₃₀:xSm³⁺ (x = 0.005–0.20) phosphors were synthesized via the solid-state reaction method. The crystal structure, photoluminescence (PL) properties, optimum concentration, color purity, decay life, and thermal stability of the samples were systematically studied. Under the excitation of 404 nm, La₇Ta₃W₄O₃₀:Sm³⁺ emits intense orange-red light at 597 nm. The PL spectra of La₇Ta₃W₄O₃₀:Sm³⁺ phosphors are ascribed to the ⁴G_5/2 to ⁶H_J (J = 5/2, 7/2, 9/2, and 11/2) transitions of Sm³⁺ ions. The concentration quenching occurs at the doping level of 1 mol%. The quenching temperature is higher than 500 K. Finally, a white LED (w-LED) with the Commission Internationale de L'Eclairage (CIE) chromaticity coordinates of (0.312, 0.296) and good color rendering index (Ra) of 86 was fabricated. As a consequence, all the results suggest that the orange-red phosphors La₇Ta₃W₄O₃₀:Sm³⁺ have potential applications in w-LEDs structures.     

Photoacoustic and photoluminescence studies on ThO<Subscript>2</Subscript>:Sm<Superscript>3+</Superscript>

Nanocrystalline ThO₂:Sm³⁺ was synthesized using wet-chemical route and characterized using X-ray diffraction (XRD), photoacoustic (PA) and photoluminescence (PL) spectroscopy. PA absorptions of Sm³⁺ doped samples are found to be quite weak as compared to Nd³⁺, while PL of Sm³⁺ was intense. As the energy gap between lowest luminescent levels and highest non-luminescent level in samarium ion is around 7000 cm^?1; it is highly fluorescing compared to Nd³⁺ which has close by levels. Through photoacoustic data it was pointed out that large covalent character exists in ThO₂:Nd³⁺ compared to ThO₂:Sm³⁺.     

M5(PO4)3F (M=Ca, Sr, Ba)中Sm3+的电荷迁移态及Sm3+和Eu3+的电荷迁移能量关系

采用高温固相反应合成了M_5-2xSm_xNa_x(PO₄)₃F(M=Ca,Sr,Ba)荧光体,研究了其在真空紫外-可见光范围的发光特性。发现在Ca₅(PO₄)₃F中Sm³⁺的电荷迁移带约在191 nm,在Sr₅(PO₄)₃F中约在199 nm,而在Ba₅(PO₄)₃F中约在204 nm,随着被取代碱土离子半径的增大电荷迁移能量逐渐减小。比较了M₅(PO₄)₃F (M=Ca,Sr,Ba)中Sm³⁺和Eu³⁺电荷迁移能量的关系。     

Structural and luminescent study in lanthanide doped sol–gel glass–ceramics comprising CeF<Subscript>3</Subscript> nanocrystals

Sol–gel derived glass–ceramics containing CeF₃ nanocrystals have been developed for the first time, to the best of our knowledge, by adequate heat treatments of precursor bulk glasses with composition 95SiO₂–5CeF₃ doped with 0.1 Eu³⁺ or 0.1 Sm³⁺ and co-doped with 0.3 Yb³⁺ and 0.1 Er³⁺ ions (in mol%). X-Ray Diffraction and High Resolution Transmission Electron Microscopy confirm the precipitation of CeF₃ nanocrystals. Moreover, this structural analysis is completed using Eu³⁺ and Sm³⁺ as probe ions of the different local environments for rare-earth ions in the nano-structured glass–ceramics. Luminescence measurements led us to discern the final environments for the ions, revealing the partition of a large fraction of these ions into like-crystalline environment of the precipitated CeF₃ nanocrystals. Near infrared emission at 1.5 μm was observed after excitation at 980 nm in Yb³⁺–Er³⁺ co-doped samples for potential applications in telecommunications.     

Tune color of single-phase LiGd(MoO4)2-X(WO4)X: Sm3+, Tb3+ via adjusting the proportion of matrix and energy transfer to create white-light phosphor

A series of LiGd(MO₄)₂: Sm³⁺, Tb³⁺ (M = Mo, W) phosphors was prepared by a conventional solid state reaction method. Powder X-Ray diffraction (XRD) analysis reveals that the compounds are of the same structure type. Their luminescent properties have been studied. The optimal doping concentrations are 8% for Sm³⁺ and 18% for Tb³⁺ in the LiGd(MoO₄)₂ host. Sm³⁺ and Tb³⁺ have different sensitivity to the Mo/W ratio. For LiGd(MoO₄)_2-X(WO₄)_X: Sm³⁺ (X = 0, 0.4, 0.8, 1.2, 1.6, 2.0), the strongest emission intensity is 1.766 times than that of the weakest, while 171 times for LiGd(MoO₄)_2-X(WO₄)_X: Tb³⁺. The experimental results show that Mo/W ratio strong influences on the properties of LiGd(MoO₄)_2-X(WO₄)_X: Tb³⁺. With the increasing of WO₄²⁻ groups concentration, the shape of characteristic excitation peaks of Tb³⁺ is almost the same and the excitation intensity gradually increase. Moreover, the energy transfer from Tb³⁺ to Sm³⁺ has been realized in the co-doped phosphors. The experimental analysis and theoretical calculations reveal that the quadrupole–quadrupole interaction is the dominant mechanism for the Tb³⁺→Sm³⁺ energy transfer. Therefore, luminous intensity can be adjusted by different sensitivities to matrix composition and energy transfer from Tb³⁺→Sm³⁺. By this tuning color method, white-light-emitting phosphor has been prepared. The excitation wavelength is 378 nm, and this indicates that the white-light-emitting phosphor could be pumped by near-UV light.     

Kinetic investigation for sorption of europium and samarium from aqueous solution using resorcinol–formaldehyde polymeric resin

Kinetic study for Eu³⁺ and Sm³⁺ sorption on resorcinol–formaldehyde (RF) polymeric material has been performed using batch method. The sorption process of Eu³⁺ and Sm³⁺ was carried out at different contact time, pH of medium, initial ion concentration and temperature. The experimental data indicated that, RF could be used as an efficient sorbent for Eu³⁺ and Sm³⁺. The sorption kinetic for Eu³⁺ and Sm³⁺ onto RF polymeric resin takes about 1 h to reach equilibrium which is considered as a fast kinetic process. Sorption results were fitted using different kinetic models such as pseudo-first-order, pseudo-second order and intraparticle diffusion models. The results indicated that the sorption of both Eu³⁺ and Sm³⁺ onto RF resin is highly fit with the pseudo-second order model. Moreover, the obtained results showed that the maximum separation factor between Eu³⁺ and Sm³⁺ was obtained at pH 3. Therefore, RF resin is considered as a promising material for sorption of Eu³⁺ and Sm³⁺ form aqueous solution.     

Synthesis of Sm-doped strontium barium niobate crystals in glass by samarium atom heat processing

New glasses giving the crystallization of Sm³⁺-doped Sr_xBa_1−xNb₂O₆ (SBN) ferroelectrics have been developed in the Sm₂O₃−SrO−BaO−Nb₂O₅−B₂O₃ system, and the formation of SBN crystal dots and lines by continuous wave Nd:YAG laser (wavelength:1064 nm, power: 1 W) irradiations, i.e., samarium atom heat processing, has been examined. The formation of Sm³⁺-doped SBN non-linear optical crystals is confirmed from X-ray diffraction analyses, micro-Raman scattering spectra, second harmonic generations, and photoluminescence spectra. Sm³⁺-doped SBN crystal dots with the diameters of 20-70 μm and lines with the widths of 20-40 μm are written at the surface of some glasses such as 10Sm₂O₃·10SrO·10BaO·20Nb₂O₅·50B₂O₃ (mol%) by Nd:YAG laser irradiations with the irradiation times of 20-70 s for the dots and with the scanning speeds of 1-5 μm/s for the lines. The present study suggests that the samarium atom heat processing has a potential for the patterning of optical waveguides consisting of ferroelectric SBN crystals in glass substrates.     

Calorimetric determination of the heats of formation of lanthanide monosulfate complexes in D2O1

Heats of formation of rate-earth monosulfate complexes have been measured calorimetrically for the ions La³⁺, Sm³⁺, Tb³⁺, and Er³⁺, in D₂O and H₂O solvents. Within the limits of experimental error there is no evidence for a solvent isotope effect on the heat and entropy changes of these complexation reactions.This paper was abstracted from W.D.W.'s Ph.D. dissertation, May 1973.     

Preparation, characterization and the standard enthalpy of formation of La0.95MnO3+δ and Sm0.95MnO3+δ

Among the perovskites, the rare earth manganites find application in several electrochemical devices because of their enhanced thermodynamic stability. In this paper, we present the results obtained on the preparation and characterization of La_0.95MnO_3+δ and Sm_0.95MnO_3+δ which were prepared by the solid state and sol–gel methods. XRD characterization of the manganites indicated that the crystal structure depends on the method of preparation and heat treatments. The ratio of Mn³⁺ to Mn⁴⁺ in these samples also depended on the method of preparation and heat treatments, as indicated by thermogravimetric (TG) and temperature programmed reduction (TPR) studies in Ar + 5% H₂ atmosphere. The standard molar enthalpy of formation, which is a measure of the thermodynamic stability of these compounds were determined using an isoperibol calorimeter.     

Effect of Sm3+ substitution on dc electrical resistivity and magnetic properties of Ni–Co ferrites

Sm³⁺ substituted Ni–Co ferrite materials have been developed with the chemical compositions Ni_0.5Co_0.5Fe_2-xSm_xO₄ for x = 0.0, 0.02, 0.04, and 0.06 by solid-state method. A spinel with a single-phase cubic structure was found through XRD analysis. Crystallite size and lattice parameter fluctuation with Samarium content, decreasing with Sm³⁺ doping. When Sm³⁺ is doped, SEM shows a uniform distribution of grains with increasing agglomeration, and the grain size decreases with samarium concentration. Two peaks of absorption mode FTIR spectra show their spinel nature. The samples' negative temperature coefficient measured by the two probe method indicates their semiconducting nature. The DC electrical resistivity of the Ni–Co ferrite system was found to increase from 5.99 × 10³ ($\text{Ω}$-cm) to 9.89 × 10⁹ ($\text{Ω}$-cm) as an increase in Sm concentration. VSM measurement gives the saturation magnetization for the concentration up to x = 0.04 decreased and then increased for x = 0.06. All these properties show our samples' higher applicability in various electronic devices.     

Anodic Dissolution of Samarium in an Acetonitrile Solution in Acetylacetone

Electrochemical dissolution of metallic samarium is studied in an acetonitrile solution containing 0.1 M tetraethylammonium bromide and 0.9 M acetylacetone. The study is performed in an argon atmosphere, at a constant voltage of 3 V and various ratios between the cathode and anode areas. If the cathode area considerably exceeds the anode area, as a result of anodic oxidation of samarium, ions Sm³⁺ form in solution, undergo reduction to Sm²⁺, and 20–25 min later generate chelate complex Sm₄(AA)₈ · 3HAA, which is insoluble in acetonitrile. Simultaneously, Sm³⁺ interacts with deprotonated acetylacetone. Chelate complex Sm(AA)₃ · HAA is extracted from solution. If the anode area exceeds the cathode area, no reduction of Sm³⁺ to Sm²⁺ occurs on the cathode, and eventually adducted samariumtris–acetylacetonate Sm(AA)₃ · 4HAA is extracted from solution. The composition of the obtained compounds is confirmed by IR and mass spectrometry, thermogravimetry, isothermic heating, and elemental analysis for metal.     

Photoluminescence of samarium-doped TiO2 nanotubes

Samarium (Sm)-modified TiO₂ nanotubes (TNTs) were synthesized by low-temperature soft chemical processing. X-ray powder diffraction analyses of the synthesized Sm-doped and non-doped TNTs show a broad peak near 2θ=10°, which is typical of TNTs. The binding energy of Sm ³d_5/2 for 10 mol% Sm-doped TNT (1088.3 eV) was chemically shifted from that of Sm₂O₃ (1087.5 eV), showing that Sm existed in the TiO₂ lattice. Sm-doped TNTs clearly exhibited red fluorescence, corresponding to the doped Sm³⁺ ion in the TNT lattice. The Sm-doped TNT excitation spectrum exhibited a broad curve, which was similar to the UV–vis optical absorption spectrum. Thus, it was considered that the photoluminescence emission of Sm³⁺-doped TNT with UV-light irradiation was caused by the energy transfer from the TNT matrix via the band-to-band excitation of TiO₂ to the Sm³⁺ ion.