Nd^(3+):GdScO_(3)晶体场能级及拟合分析

采用提拉法生长出了钕掺杂钪酸钆晶体(Nd^(3+):GdScO_(3)),通过低温吸收光谱和室温发射光谱,对其中Nd^(3+)的实验能级进行分析指认,确定了Nd^(3+):GdScO_(3)的66个实验Stark能级,拟合了其自由离子参数和晶体场参数,拟合均方根误差为13.17 cm^(–1).与Nd^(3+):YAP和Nd^(3+):YAG相比,Nd^(3+):GdScO_(3)的晶场强度较弱.弱的晶体场强度有可能是Nd^(3+):GdScO_(3)晶体具有优良激光特性的原因之一.本文数据集可在https://www.doi.org/10.57760/sciencedb.15702中访问获取.

Nd^(3+)掺杂钙钛锆石(Ca_(1-x)Nd_(x)ZrTi_(2)O_(7+x/2))相变行为的研究

为研究钙钛锆石对放射性元素Am^(3+)的稳定固化作用,以Nd^(3+)为Am^(3+)的模拟元素,系统研究了高温固相法制备Ca_(1-x)Nd_(x)ZrTi_(2)O_(7+x/2)时,Nd^(3+)异价取代钙钛锆石晶格中Ca^(2+)位(0≤x≤1.0)所导致的相态演变行为。合成Ca_(1-x)Nd_(x)ZrTi_(2)O_(7+x/2)的XRD、Raman、BSE和EDS测试结果表明:钙钛锆石(Zirconolite)晶格对Nd^(3+)离子的固溶量可达70%(x=0.7),可有效实现对Am^(3+)模拟元素Nd^(3+)离子的固化。但随着Nd^(3+)掺杂量(x≤0.3)增加,Zirconolite-2M晶格中O^(2-)和Nd^(3+)的无序化程度逐渐增加、(Ca/Nd)-O键长逐渐变小,直至(x=0.4)引起Zr^(2+)、Ti^(4+)附近的O^(2-)配位数发生改变(ZrO7→ZrO8、TiO5→TiO6),Zirconolite-2M晶格结构开始向Zirconolite-4M转变。x=0.5时,陶瓷体完全转变为Zirconolite-4M晶格且O^(2-)和Nd^(3+)有序度重新变高、Ti—O键长增加;直至x=0.6、x=0.7时,陶瓷体仍为单一Zirconolite-4M结构,但晶格中O^(2-)和Nd^(3+)的有序度又逐渐降低,以至于在x=0.7陶瓷体亚晶格中微量Ca^(2+)、Zr^(4+)、Nd^(3+)离子占位转变为烧绿石(Pyrochlore)结构。而在0.8≤x≤0.9范围内,Zirconolite-4M结构完全消失,陶瓷体为多相共存状态(Pyrochlore、ZrTiO_(4)和Nd2(TiZr)_(4)O_(11)物相)。Nd^(3+)完全取代Ca^(2+)位(x=1.0)时,陶瓷体变为单一Nd2(TiZr)_(4)O_(11)固溶体相。陶瓷体晶粒的BSE和EDS分析证实了这种相变规律。

Yb^(3+)/Nd^(3+)掺杂对Sr_(9)Ga(PO_(4))_(7)∶Cr^(3+)发光性能的影响

近红外荧光粉由于其独特的物理特性和广阔的应用前景吸引了人们极大的研究兴趣。本文通过高温固相反应法合成Sr_(9)Ga(PO_(4))_(7)∶0.8Cr^(3+)近红外荧光粉,使用460 nm蓝光激发样品的发射波长位于833 nm,半峰宽为117 nm。随后引入稀土离子合成Sr_(9)Ga(PO_(4))_(7)∶0.8Cr^(3+),Yb^(3+)和Sr_(9)Ga(PO_(4))_(7)∶0.8Cr^(3+),Nd^(3+)近红外荧光粉。相比Sr_(9)Ga(PO_(4))_(7)∶0.8Cr^(3+),460 nm蓝光激发的Sr_(9)Ga(PO_(4))_(7)∶0.8Cr^(3+),Yb^(3+)同时出现Cr^(3+)和Yb^(3+)特征发射峰,经过光谱分析和荧光寿命变化证明Cr^(3+)-Yb^(3+)存在能量传递通道,最高使Cr^(3+)-Yb^(3+)能量传递效率达80.2%,得益于Yb^(3+)卓越的热稳定性促使整体荧光光谱热稳定性提高约3.7倍。设计合成的Sr_(9)Ga(PO_(4))_7∶0.8Cr^(3+),Nd^(3+)样品调制出833,876,1 060 nm的多峰发射,显著拓宽了近红外光谱范围。最终,讨论了荧光粉在温度传感和无损检测领域的应用,证明该系列荧光粉具有广阔的应用前景。

Self-assembled S-scheme In_(2.77)S_(4)/K^(+)-doped g-C_(3)N_(4)photocatalyst with selective O_(2) reduction pathway for efficient H_(2)O_(2) production using water and air

The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In_(2.77)S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2) production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In_(2.77)S_(4)/respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In_(2.77)S_(4) according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2) production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2) around the active centers,the energy barriers of O_(2) protonation and H_(2)O_(2) desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2) photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.

First-Principles Investigation of Charge Transfer Mechanism of B-Doped 3C-SiC Semiconductor Material

This study delves into the charge transfer mechanism of boron (B)-doped 3C-SiC through first-principles investigations. We explore the effects of B doping on the electronic properties of 3C-SiC, focusing on a 12.5% impurity concentration. Our comprehensive analysis encompasses structural properties, electronic band structures, and charge density distributions. The optimized lattice constant and band gap energy of 3C-SiC were found to be 4.373 Å and 1.36 eV respectively, which is in agreement with previous research (Bui, 2012;Muchiri et al., 2018). Our results show that B doping narrows the band gap, enhances electrical conductivity, and influences charge transfer interactions. The charge density analysis reveals substantial interactions between B dopants and surrounding carbon atoms. This work not only enhances our understanding of the material’s electronic properties, but also highlights the importance of charge density analysis for characterizing charge transfer mechanisms and their implications in the 3C-SiC semiconductors.

Fabrication of Gd_(2)O_(3)-doped CeO_(2)thin films through DC reactive sputtering and their application in solid oxide fuel cells

Physical vapor deposition(PVD)can be used to produce high-quality Gd_(2)O_(3)-doped CeO2(GDC)films.Among various PVD methods,reactive sputtering provides unique benefits,such as high deposition rates and easy upscaling for industrial applications.GDC thin films were successfully fabricated through reactive sputtering using a Gd_(0.2)Ce_(0.8)(at%)metallic target,and their application in solid oxide fuel cells,such as buffer layers between yttria-stabilized zirconia(YSZ)/La0.6Sr0.4Co0.2Fe0.8O_(3−δ)and as sublayers in the steel/coating system,was evaluated.First,the direct current(DC)reactive-sputtering behavior of the GdCe metallic target was determined.Then,the GDC films were deposited on NiO-YSZ/YSZ half-cells to investigate the influence of oxygen flow rate on the quality of annealed GDC films.The results demonstrated that reactive sputtering can be used to prepare thin and dense GDC buffer layers without high-temperature sintering.Furthermore,the cells with a sputtered GDC buffer layer showed better electrochemical performance than those with a screen-printed GDC buffer layer.In addition,the insertion of a GDC sublayer between the SUS441 interconnects and the Mn-Co spinel coatings contributed to the reduction of the oxidation rate for SUS441 at operating temperatures,according to the area-specific resistance tests.

溶液燃烧法制备Nd^(3+)掺杂LaBO_(3)荧光粉

以La(NO_(3))_(3)·6H_(2)O、H_(3)BO_(3)为原料、C_(2)H_(5)NO_(2)为燃烧剂、Nd(NO_(3))_(3)·6H_(2)O为改性剂,通过溶液燃烧法合成Nd^(3+)掺杂LaBO_(3)荧光粉。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射光谱(UV-Vis DRS)以及荧光光谱(PL)对产物进行表征分析。结果表明,制备的粉体均为正交晶系硼酸镧,在煅烧温度875℃、Nd^(3+)掺杂量3%的优化条件下制备的硼酸镧荧光粉发光性能最好,且其在紫外光区和可见光区均表现出良好的光吸收性能,发蓝绿色光,可广泛应用于激光照明和LED照明等领域。

Nd^(3+)掺杂磷酸盐激光玻璃猝灭浓度的计算与预测

通过研究稀土离子在玻璃中激发态布居数与掺杂浓度之间的关系,建立了一种半定量的激光玻璃发光猝灭浓度预测的研究方法。研究发现,在Nd^(3+)掺杂磷酸盐玻璃中,无辐射跃迁速率与浓度的线性相关性大于其与浓度的平方相关性,表明OH-对无辐射跃迁几率的影响大于稀土离子之间的能量传递过程。选择低浓度下的荧光寿命代替自发辐射跃迁寿命预测猝灭浓度,有效降低了多声子弛豫以及OH-的影响,预测发光猝灭浓度与实验值的绝对误差从0.82%降低到了0.16%。本文所提出的预测计算方法具有较高的准确性和普适性,这为理论预测激光玻璃的猝灭浓度提供了一定的指导意义,有助于新型激光玻璃的研究和探索。

具有光热转换能力的近红外光学测温材料BaY_(2)O_(4)∶Nd^(3+)

光热治疗亟需一种准确、高效、分辨率高且适用于深层生物组织的测温手段以辅助其治疗过程。本文以高温固相法合成了BaY_(2)O_(4)∶Nd^(3+)材料,并基于Nd^(3+):^(4)F_(3/2)的Stark劈裂能级实现了较为精准的光学测温。数据表明,其测温的绝对灵敏度、相对灵敏度及分辨率的最佳值可分别达到0.09%·K^(-1)、0.69%·K^(-1)和0.05 K,优于大多数同类型温度计的相应数值。与此同时,因该光学温度计的激发和发射波长均位于生物窗口之内,使其在生物组织中的穿透深度可达到8 mm。另外,该材料还具有一定的光热转换能力。上述结果表明,Nd^(3+)单掺的Ba Y_(2)O_(4)在深层组织的光热治疗方面具备一定的应用潜力。

Spectroscopic Properties of Nd^(3+)-Doped Tellurite Glasses

The Nd^3＋-doped pared. The absorption and tellurite glasses were preemission spectra of Nd^3 ＋- doped tellurite glasses at room temperature were measured. The Judd-Ofelt parameters （Ω2, Ω4, Ω6） of the glasses were calculated from measured absorption spectra. The calculation results of luminescence properties （A, β, τrad, σ） of Nd^3＋ ions in the tellurite were glasses were given. Spectroscopic properties, concentration quenching in these kinds of the glasses were investigated. The results indicate that the tellurite glasses with composition of 70% TeO2, 20% ZnO, （ 10 - x ） % La2O3, x % Nd2O3 （ mol% ） show high emission cross section and low phonon energy. The fluorescent intensity and the emission cross section have a maxi- mum value at x = 0.5, namely, the optimum Nd^3 ＋ ion concentration in the tellurite glass is 0.5% （1.93 × 10^20 ions·cm^-3）. The fluorescence properties of Nd^3＋ measured are basically in accord with the calculated results.

Ca_(2)MnO_(4)-layered perovskite modified by NaNO_(3)for chemical-looping oxidative dehydrogenation of ethane to ethylene

Chemical-looping oxidative dehydrogenation(CL-ODH)is a process designed for the conversion of alkanes into olefins through cyclic redox reactions,eliminating the need for gaseous O_(2).In this work,we investigated the use of Ca_(2)MnO_(4)-layered perovskites modified with NaNO_(3) dopants,serving as redox catalysts(also known as oxygen carriers),for the CL-ODH of ethane within a temperature range of 700-780℃.Our findings revealed that the incorporation of NaNO_(3) as a modifier significantly-nhanced the selectivity for-thylene generation from Ca_(2)MnO_(4).At 750℃and a gas hourly space velocity of 1300 h^(-1),we achieved an-thane conversion up to 68.17%,accompanied by a corresponding-thylene yield of 57.39%.X-ray photoelectron spectroscopy analysis unveiled that the doping NaNO_(3) onto Ca_(2)MnO_(4) not only played a role in reducing the oxidation state of Mn ions but also increased the lattice oxygen content of the redox catalyst.Furthermore,formation of NaNO_(3) shell on the surface of Ca_(2)MnO_(4) led to a reduction in the concentration of manganese sites and modulated the oxygen-releasing behavior in a step-wise manner.This modulation contributed significantly to the enhanced selectivity for ethylene of the NaNO_(3)-doped Ca_(2)MnO_(4) catalyst.These findings provide compelling evidence for the potential of Ca_(2)MnO_(4)-layered perovskites as promising redox catalysts in the context of CL-ODH reactions.

Guiding properties of proton-implanted Nd^(3+)-doped phosphate glass waveguides

We report on the fabrication and properties of an optical waveguide in Nd^(3+)-doped phosphate glass.The planar waveguide was obtained by 550-ke V proton implantation with a dose of 8.0×10^(16)ions/cm^(2).The proton–glass interaction was simulated by the stopping and range of ions in matter(SRIM software).The characteristics of the waveguide including the refractive index profile and the near-field intensity distribution were studied by the reflectivity calculation method and the end-face coupling technique.The optical waveguide demonstrated multi-mode behavior at the wavelength of 632.8 nm.The propagation features of the proton-implanted Nd^(3+)-doped phosphate glass waveguide shows its potential to operate as an integrated photonic device.

Spectroscopic Properties of Nd^(3+)-Doped High Silica Glass Prepared by Sintering Porous Glass

A new kind of Nd^3＋-doped high silica glass （SiO2 〉 96% （mass fraction）） was obtained by sintering porous glass impregnated with Nd^3 ＋ ions. The absorption and luminescence properties of high silica glass doped with different Nd^3 ＋ concentrations were studied. The intensity parameters Ωt （t = 2, 4, 6）, spontaneous emission probability, fluorescence lifetime, radiative quantum efficiency, fluorescence branching ratio, and stimulated emission cross section were calculated using the Judd-Ofelt theory. The optimal Nd^3＋ concentration in high silica glass was 0.27% （mole fraction） because of its high quantum efficiency and emission intensity. By comparing the spectroscopic parameters with other Nd^3 ＋- doped oxide glasses and commercial silicate glasses, the Nd^3 ＋ -doped high silica glasses are likely to be a promising material used for high power and high repetition rate lasers.

P204-P507在酸性硫酸盐溶液中对Nd^3＋和Sm^3＋的协同萃取

采用恒摩尔法、斜率法以及饱和容量法研究从硫酸介质中用P204(D2EHPA,用(HA)2表示)与P507(HEHEHP,用(HL)2表示)协同萃取Nd3+或Sm3+的性能与机理,并测定协萃反应的热力学平衡常数Ks.e,求得反应的焓变和熵变。结果表明,萃取反应呈现正协同效应,且协萃过程为放热反应,协萃配合物组成分别为Nd.(HA2)2.HL2和Sm.(HA2)2.HL2。因此,P204与P507混合使用可以改善硫酸介质下稀土的萃取分离效果。

掺Nd^(3+)激光材料的研究进展

介绍了掺Nd3+激光离子晶体、陶瓷、玻璃和微晶玻璃材料的研究现状,比较了各种掺Nd3+激光材料的性能,分析了不同的掺Nd3+激光材料的各自用途,评述了有代表性的掺Nd3+激光材料的光谱和激光特性,讨论了掺Nd3+激光材料研究和应用方面的发展趋势。

Nd^3＋离子掺杂YAG激光透明陶瓷的光谱性质及Judd-Ofelt理论分析

采用固相反应和真空烧结技术制备了掺杂浓度为1.0at%的Nd:YAG透明陶瓷样品,并测试了样品的吸收光谱和荧光光谱.样品在主吸收峰808nm处的吸收截面为3.10×10^(-20)cm^2,主荧光发射峰位于1064nm处,实测荧光寿命为257μs.应用Judd-Ofelt理论计算了Nd^(3+)在YAG中的强度参数Ω_λ(λ=2,4,6)、跃迁的振子强度、自发辐射跃迁几率、辐射寿命、荧光分支比等光谱参数.最后计算得到Nd:YAG透明陶瓷中Nd^(3+):~4F_(3/2)→I_(11/2)跃迁对应的受激发射截面大小为3.81×10^(-19)cm^2.结果表明:Nd:YAG透明陶瓷具有较大的受激发射截面和高的荧光量子效率(接近100%),是一种性能优良的激光材料.

固化杨梅单宁对Nd^(3+)的吸附效果实验研究

固化杨梅单宁(IMT)是以胶原纤维为基质,通过醛交联剂将杨梅单宁固化在胶原纤维上所制备的吸附材料。研究了该吸附材料对稀土元素Nd3+的富集性能。实验表明:该吸附材料对Nd3+的吸附平衡量受温度和pH的影响。在293~323 K时,Nd3+的吸附平衡量随温度的升高而增加。pH值对吸附平衡量影响较大,在pH为3.5~5.5范围内,吸附量随pH升高而增加。当pH≥6时,吸附量开始逐渐下降。吸附平衡符合Freundlich方程。研究表明,吸附动力学可用拟二级速度方程来描述,由拟二级速度方程计算所得到的吸附平衡量与实测值的偏差在4%以内,具有很好的一致性。其吸附性能为稀土生产工业废液中稀土金属的回收,微痕量Nd3+的富集和测试,以及单一稀土的绿色分离提供了科学依据。

胶原纤维固化杨梅单宁对Pr^(3+),Nd^(3+)的吸附特性

以胶原纤维为基质,通过醛交联剂将杨梅单宁固化在胶原纤维上制备吸附材料。研究了该吸附材料对稀土元素Pr3+,Nd3+的吸附性能。结果表明:温度在293K^323K的范围内,Pr3+,Nd3+的吸附平衡量随温度的升高略有增加。pH值对吸附平衡量影响较大,在pH值为3.5~5.0范围内,吸附量随pH值升高而增加。当pH≥5.0时,吸附量开始逐渐下降。吸附动力学可用拟二级速率方程来描述,由拟二级速率方程计算所得到的吸附平衡量与实测值的偏差在6%以内。该吸附材料适合柱上操作,吸附柱也易于再生。

Nd^(3+):KGd(WO_4)_2激光晶体的研究

合成了一系列不同Nd3+ 浓度掺杂的Nd3+ :KGd(WO4 ) 2 粉末样品 ,进行了荧光光谱测试 ,初步确定了Nd3+ 的最佳掺杂浓度 ;测定了Nd3+ :KGd(WO4 ) 2 K2 WO4 生长体系的生长温度曲线 ,生长出尺寸达 50mm的Nd3+ :KGd(WO4 ) 2 优质激光晶体 ,切割出尺寸为 5mm× 5mm× 6mm的优质激光器件 ,采用钛宝石模拟LD泵浦 ,在 1.0 6 μm处得到 2 6 0mW的激光输出 ,斜率效率达到 6 6 % ;在 1.0 3μm处得到 135mW激光输出 ,斜率效率达到 34.3%。

LD泵浦Nd^(3+)∶GdVO_4/Cr^(4+)∶YAG固体激光器

通过合理设计,精密调控各元件和温控电流,得到了平均功率为70mW,脉冲宽度为22ns,重复频率为14kHz,峰值功率高达230W的Nd3+∶GdVO4/Cr4+YAG绿光脉冲激光器·腔外采用望远镜系统聚焦,经KTP晶体倍频后,得到了平均功率为28.8mW,脉冲宽度为19ns,重复频率为14kHz,峰值功率高达108W的绿光激光输出,转换效率高达·指出了小光斑对倍频晶体带来的影响·