Properties Of Yb Research Articles

Passivation phenomenon and variable properties of ytterbium in different Lewis acid AlCl3-NaCl melts

To further explore the application of the low-temperature molten salt in processing heavy rare earths, the properties of ytterbium in AlCl3-NaCl melts have been investigated. In this melt, YbCl2 powder products are prepared by electrolysis based on the dissolution reaction of Yb metal. The properties of Yb(II) in AlCl3-NaCl melts have also been studied in detail. In-situ UV–VIS absorption spectroscopy demonstrates that the coordination of Yb(II) changes in AlCl3-NaCl melts with different Lewis acidity, leading to variations in its diffusion ability. In addition, the conversion of Yb(II)/Yb(III) shows typical soluble-soluble reversible electrochemical behavior in strongly acidic AlCl3-NaCl. However, the electrochemical behavior of Yb(II) on inert electrodes becomes complicated when the amount of AlCl3 in AlCl3-NaCl melts less than 52 mol%. This change is attributed to the formation of a YbCl3 passivation film on the inert electrode during the electro-oxidation of Yb(II). Soaking the passivated electrode in the melt can alleviate the passivation. Understanding the electrochemical and spectroscopic properties of ytterbium in AlCl3-NaCl melts paves the way for its subsequent applications.

Effect of SiC whiskers on the anti‐oxidation properties of Yb2Si2O7/mullite/SiC tri‐layer environmental barrier coating for CMCs

AbstractThe mullite and ytterbium disilicate (β‐Yb2Si2O7) powders as starting materials for the Yb2Si2O7/mullite/SiC tri‐layer coating are synthesized by a sol–gel method. The effect of SiC whiskers on the anti‐oxidation properties of Yb2Si2O7/mullite/SiC tri‐layer coating for C/SiC composites in the air environment is deeply studied. Results show that the formation temperature and complete transition temperature of mullite were 800–1000 and 1300°C, respectively. Yb2SiO5, α‐Yb2Si2O7, and β‐Yb2Si2O7 were gradually formed between 800 and 1000°C, and Yb2SiO5 and α‐Yb2Si2O7 were completely transformed into β‐Yb2Si2O7 at a temperature above 1200°C. The weight loss of Yb2Si2O7/(SiCw–mullite)/SiC tri‐layer coating coated specimens was 0.15 × 10−3 g cm−2 after 200 h oxidation at 1400°C, which is lower than that of Yb2Si2O7/mullite/SiC tri‐layer coating (2.84 × 10−3 g cm−2). The SiC whiskers in mullite middle coating can not only alleviate the coefficient of thermal expansion difference between mullite middle coating and β‐Yb2Si2O7 outer coating, but also improve the self‐healing performance of the mullite middle coating owing to the self‐healing aluminosilicate glass phase formed by the reaction between SiO2 (oxidation of SiC whiskers) and mullite particles.

Hydrothermal Synthesis and Properties of Yb3+/Tm3+ Doped Sr2LaF7 Upconversion Nanoparticles

We report the procedure for hydrothermal synthesis of ultrasmall Yb3+/Tm3+ co-doped Sr2LaF7 (SLF) upconversion phosphors. These phosphors were synthesized by varying the concentrations of Yb3+ (x = 10, 15, 20, and 25 mol%) and Tm3+ (y = 0.75, 1, 2, and 3 mol%) with the aim to analyze their emissions in the near IR spectral range. According to the detailed structural analysis, Yb3+ and Tm3+ occupy the La3+ sites in the SLF host. The addition of Yb3+/Tm3+ ions has a huge impact on the lattice constant, particle size, and PL emission properties of the synthesized SLF nanophosphor. The results show that the optimal dopant concentrations for upconversion luminescence of Yb3+/Tm3+ co-doped SLF are 20 mol% Yb3+ and 1 mol% Tm3+ with EDTA as the chelating agent. Under 980 nm light excitation, a strong upconversion emission of Tm3+ ions around 800 nm was achieved. In addition, the experimental photoluminescence lifetime of Tm3+ emission in the SLF host is reported. This study discovered that efficient near IR emission from ultrasmall Yb3+/Tm3+ co-doped SLF phosphors may have potential applications in the fields of fluorescent labels in bioimaging and security applications.

Recent Development of High-Energy Short-Pulse Lasers with Cryogenically Cooled Yb:YAG

High-power solid-state lasers are among the hot research directions at the forefront of laser research and have major applications in industrial processing, laser-confined nuclear fusion, and high-energy particle sources. In this paper, the properties of Yb:YAG and Nd:YAG crystals as gain media for high-power solid-state lasers were briefly compared, according to the results of which Yb:YAG crystals are more suitable for high-power applications. Then, the effects of the thermodynamic and spectral properties of Yb:YAG crystals with temperature were analyzed in detail, and it was shown that the laser beams amplified by the cryogenically cooled Yb:YAG crystals could have higher beam quality, higher pump absorption efficiency, lower pump threshold, and higher gain. The change in properties of Yb:YAG crystal at low temperature makes it more suitable as a gain medium for high-power lasers. Subsequently, two types of kilowatt-class lasers using cryogenically cooled Yb:YAG crystals as gain media are introduced—100 J, 10 Hz nanosecond lasers and 1 J, 1 kHz picosecond lasers. Their configuration, main parameters, and typical output results were analyzed. Finally, future directions in the development of cryogenically cooled Yb:YAG lasers are discussed.

Influence of GeO2 Content on the Spectral and Radiation-Resistant Properties of Yb/Al/Ge Co-Doped Silica Fiber Core Glasses.

In this study, Yb/Al/Ge co-doped silica fiber core glasses with different GeO2 contents (0–6.03 mol%) were prepared using the sol–gel method combined with high-temperature sintering. The absorption, fluorescence, radiation-induced absorption, continuous-wave electron paramagnetic resonance spectra, and fluorescence decay curves were recorded and analyzed systematically before and after X-ray irradiation. The effects of GeO2 content on the valence variations of Yb3+/Yb2+ ions, spectral properties of Yb3+ ions, and radiation resistance of Yb/Al/Ge co-doped silica glasses were systematically studied. The results show that even if the GeO2 content of the sample is relatively low (0.62 mol%), it can inhibit the generation of Yb2+ ions with slight improvement in the spectral properties of Yb3+ ions in the pristine samples and effectively improve its radiation resistance. Direct evidence confirms that the generation of trapped-electron centers (Yb2+/Si-E’/Al-E’) and trapped-hole centers (Al-OHC) was effectively inhibited by Ge co-doping. This study provides a theoretical reference for the development of high-performance, radiation-r esistant Yb-doped silica fibers.

Fabrication and luminescence properties in Yb –Tb co-doped a-SiCO thin films

Fabrication and luminescence properties in Yb –Tb co-doped a-SiCO thin films

Yb:GdScO3 crystal for efficient ultrashort pulse lasers.

We present, to the best of our knowledge, the first demonstration of thermal, optical, and laser properties of Yb:GdScO3 for potentially efficient ultrashort pulse lasers. The stimulated emission cross section at 1025 nm (E//c) is 0.46×10-20cm2 with the emission band width of 85 nm, even broader than the well-known Yb:CaGdAlO4. It has quite a high thermal conductivity of 5.54W/(m⋅K) at 50°C, comparable with Yb:YAG. In the continuous-wave regime, the maximum output power of 13.45 W at 1063.9 nm was generated with the optical-to-optical efficiency of 63.3%. These results suggest that the Yb:GdScO3 crystal is a promising candidate for ultrashort pulse lasers.

Optical Properties of Yb:Lu3Al5O12 Crystal Irradiated by 4.5-MeV Si Ions

Compact waveguide laser sources emitting at wavelength around 1.0 μm are interesting in a multiple of application. In present work, we demonstrate a crystalline waveguide in Yb:Lu3Al5O12 (Yb:LuAG) crystal irradiated by 4.5-MeV Si ions at fluences of 1.0 × 10–15 cm–2. A typical “barrier-confined” waveguide geometry is confirmed by performing the prism-coupling measurement at a wavelength of 632.8 nm with transverse electric (TE) polarization, and the refractive index profile is proposed based on the dark-mode plots. Under excitation at 930 nm, the peak emission at 1030 nm is generated with a bandwidth of 14.4 nm. The fluorescence decay actions are investigated on a Jobin Yvon spectrometer. The radiative constants and peak emission cross-section values are obtained.

Effect of B2O3 addition on structure and properties of Yb3+/Al3+/B3+‐co‐doped silica glasses

AbstractThe homogeneous Yb3+/Al3+/B3+‐co‐doped silica glasses were prepared via a sol‐gel method. The impact of B2O3 addition on the physical and optical properties and network structure was systematically studied. The network structure was investigated by the Fourier Transform Infrared (FT‐IR), Raman spectra, and Solid State Nuclear Magnetic Resonance (SSNMR). Herein, B2O3 addition can continuously decrease the refractive index and density. When B2O3 is lower than 2 mol%, B2O3 addition can obviously decrease the scalar crystal field parameters, Yb3+ asymmetry degree, Yb3+ cross‐sections, due to the generation of Yb–O–B bonds at the cost of partial Yb–O–Al/Si ones. When B2O3 is more than 2 mol%, FT‐IR, Raman spectra, and SSNMR results indicate that further increased B atoms prefer to connect with Si and Al rather than Yb. Consequently, the above parameters are basically unchanged. Based on the results, an intuitive model of structure and properties evolution during the substitution of SiO2 by B2O3 has been established.

Effect of thermal annealing on structures and properties of Yb3+/Al3+/P5+ co-doped silica glasses

Homogeneous 89.9SiO2-4Al2O3-6P2O5–0.1Yb2O3/Eu2O3 glasses were fabricated via a sol−gel method and sintered under vacuum at high temperature, and subsequently they were annealed at 850 °C for 15 and 75 h. Effect of thermal annealing time on structures and properties of glasses was systematically investigated. Solid state nuclear magnetic resonance (SSNMR) and Raman scattering spectra were employed to characterize the network structures. Pulse electron paramagnetic resonance (EPR) techniques and the emission and excitation spectra of Eu3+ ions were used to study the local environment of Yb3+ ions. SSNMR and Raman results indicate that AlPO4 units increase at the expense of AlV, AlVI and P(3) groups after annealing. The glass network structures have a significant influence on density and refractive index. EPR and Eu3+ spectra indicate an increase in Al around Yb3+ ions and a reduction in the asymmetry degree of Yb3+ ligands. A correlation between structures and properties of glasses is developed.

Fabrication and laser operation of Yb:Lu2O3 transparent ceramics from co‐precipitated nano‐powders

AbstractIn this article, 5 at.% Yb:Lu2O3 transparent ceramics were fabricated by vacuum sintering combined with hot isostatic pressing (HIP) posttreatment using co‐precipitated nano‐powders. The influence of precipitant molar ratio, ammonium hydrogen carbonate, to metal ions (AHC/M3+, R value) on the properties of Yb:Lu2O3 precursors and calcined powders was investigated systematically. It was found that the powders with different R value calcined at 1100°C for 4 hours were pure cubic Lu2O3 but the morphologies of precursors and powders behaved differently. The opaque samples pre‐sintered at 1500°C for 2 hours grew into transparent ceramics after HIP posttreatment at 1750°C for 1 hour. The final ceramic with R = 4.8 showed the best optical quality with the in‐line transmittance of 79.7% at 1100 nm. The quasi‐CW laser operation was performed at 1034 nm and 1080 nm with a maximum output power up to 8.15 W as well as a corresponding slope efficiency of 58.4%.

Effect of GeO2 on structure and properties of Yb: Phosphate glass

The structure evolution and relationship between structure and properties of Yb3+-doped phosphate glasses with adding GeO2 from 0 to 450 wt% (marked as PG) were analyzed using Tg, Yb3+ local environment parameters, XRD, infrared and Raman spectra. The formation of Ge-O-P was valuable for improving spectroscopic properties at low germanium oxide (GeO2 < 20 wt%). However, the broadening of XRD scattering package and the reduction of Tg indicated that two networks of P-O and Ge-O emerged in the case of high germanium oxide (20 wt% < GeO2 < 100 wt%). Furthermore, under ultra-high germanium oxide (GeO2 > 100 wt%), some significant macroscopic phase separation phenomena were observed by XRD, absorption spectra, double fluorescence lifetime, SEM and EPMA measurements. A component-property evaluation criterion for optimizing Stark splitting and spectroscopic properties was suggested by comprehensive evaluation of the glass stability, Stark splitting, spectral properties and phase separation of Yb3+-doped PG glass system, i.e., the appropriate proportions of O/(P + Ge) and P/Ge were 2.87–2.96 and 4.36–8.71, respectively.

P concentration dependence of local structure around Yb3+ ions and optical properties in Yb–P-doped silica glasses

Local structure around Yb3+ ions in Yb–P-doped silica glasses and its P concentration dependence were elucidated by EXAFS measurements. Yb–O coordination number was found to change from 4 → 8 → 6 → 7 ∼ 8 with increasing the atomic ratio P/Yb. This strange change can be corresponded to the local structure changes in the order of YbPO4-like, Yb(PO3)3-like to YbP5O14-like local structures. This correspondence is supported by various optical measurements, such as the Rayleigh/Mie scattering, Raman scattering, absorption cross-section, CT transition, and X-ray induced defect formation, which were also found to depend on P/Yb. These results provide a guideline of the suitable P concentration in RE-P-doped silica glasses for various applications.

Defect properties in Yb3+-doped CaF2 from first-principles calculations: a route to defect engineering for up- and down-conversion photoluminescence

The formation energy, transition level and binding energy of defects in Yb3+-doped CaF2 were calculated with DFT/HSE06.

Bioimaging: Shaping Luminescent Properties of Yb3+ and Ho3+ Co‐Doped Upconverting Core–Shell β‐NaYF4 Nanoparticles by Dopant Distribution and Spacing (Small 47/2017)

Bioimaging: Shaping Luminescent Properties of Yb³⁺ and Ho³⁺ Co‐Doped Upconverting Core–Shell β‐NaYF₄ Nanoparticles by Dopant Distribution and Spacing (Small 47/2017)

Fuel combustion synthesis and upconversion properties of Yb3+ and Er3+ dual-doped ZrO2 nanocrystals

Ytterbia and erbia dual-doped zirconia (ZrO2: Yb3+, Er3+) nanophosphors were successfully synthesized by high-temperature fuel combustion at 1000 °C for 2 h. The effects of dopant concentration on the structure and upconversion properties were investigated by X-ray diffraction, transmission electron microscopy and photoluminescence, respectively. XRD patterns indicate that the main phase of products belongs to cubic ZrO2 fluorite-type structure. TEM results show that different fuels have great influence on the morphologies of dual-doped ZrO2 samples. Under 980 nm excitation, the glycine-calcined nanophosphors show high stimulated luminescence and doped-ion concentration-depended intensities. The intensely red upconversion emissions are attributed to the fact that the dual-doped Yb3+ and Er3+ ions result in the non-radiative relaxation, energy migration, and cross relaxation.

Anisotropy in spectroscopic and laser properties of Yb:Sr_3La_2(BO_3)_4 disordered crystal

We report, for the first time to our knowledge, on the polarized absorption and emission spectra and efficient laser action of the Yb:Sr3La2(BO3)4 disordered crystal. The strongest absorption and emission occur at about 977 nm for polarization direction parallel to the crystallographic b axis, with the peak absorption and emission cross-sections amounting, respectively, to 1.95 × 10−20 and 2.45 × 10−20 cm2. Efficient continuous-wave laser action is demonstrated with a-, b-, and c-cut crystal samples longitudinally pumped by a 976-nm diode laser, producing an output power of up to 8.2 W with an optical-to-optical efficiency of 32% with respect to incident pump power. Depending on the output coupling utilized, the laser action could exhibit a transition from single-polarization oscillation to dual-orthogonal-polarization oscillation at a certain pump level.

Preparation and Properties of Yb:YAG and Nd:YAG Nanocrystals

Yb:YAG and Nd:YAG nanocrystals were synthesized by a ultrasound-microwave-assisted alkoxide hydrolysis precipitation method. The effect of reaction parameters including the microwave radiation power, microwave radiation time and calcination temperature on the composition of the products was investigated. The Yb:YAG and Nd:YAG nanocrystals were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and photoluminescence (PL) spectrum. The results show that the pure phase Yb:YAG and Nd:YAG nanocrystals can be obtained at microwave radiation power of 385 W, microwave radiation time of 30 min and calcination temperature of 1100 °C. The cooperative luminescent intensities of the Yb:YAG and Nd:YAG nanocrystals reach the maximum at the calcination temperature of 1100 °C.

Synthesis and Optical Properties of Yb3+/Er3+, Yb3+/Tm3+, Eu3+ Doped NaLuF4, Na5Lu9F32, KLu3F10, and KLu2F7

Synthesis and Optical Properties of Yb³⁺/Er³⁺, Yb³⁺/Tm³⁺, Eu³⁺ Doped NaLuF₄, Na₅Lu₉F₃₂, KLu₃F₁₀, and KLu₂F₇

Laser processing of Yb3 +/Er3 + co-doped LiYF4 thin films with up-conversion properties

We present a comparative study between the properties of Yb3+/Er3+ co-doped LiYF4 thin films obtained by pulsed laser deposition (PLD) and matrix-assisted pulsed evaporation (MAPLE) growth techniques, respectively. We performed structural, morphological, and optical analyses in order to draw a conclusion about the potential of MAPLE as a growth technique used for the obtaining of RE-doped fluoride thin films having up-conversion properties. For both techniques the surface morphology is typical for laser processed thin films of RE-doped fluorides, with roughness values of the order of few hundreds of nanometers and a higher density of defects in the sample obtained by MAPLE. Up-conversion properties do not exhibit major differences between the thin film samples and the pressed target. Under 980nm laser light pumping, both Yb3+/Er3+ co-doped LiYF4 thin film samples, obtained by PLD and MAPLE, show green ((2H11/2, 4S3/2)→4I15/2) and red (4F9/2→4I15/2) up-conversion luminescence explained by a two-photon processes. Therefore MAPLE is a viable growth technique for the fundamental study of RE-doped fluoride thin films and their respective functional properties.