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In this work, the threshold photoionization cross sections from the excited states of lutetium and ytterbium atoms were investigated by the laser pump–probe scheme under the condition of saturated resonant excitation. We obtained the resonance enhanced multiphoton ionization spectra of the lutetium and ytterbium atoms of the lanthanide metals in the range of 307.50–312.50 nm and 265.00–269.00 nm, respectively; the photoionization cross sections of the 5d6s(1D)6p(2D05/2) and 5d6s(3D)6p(2P01/2) states of lutetium and the 4f13(2F0)5d6s2(J = 1) states of ytterbium above threshold regions (0.4–1.6 eV) were measured, and measured values ranged from 2.3 ± 0.2 to 17.7 ± 1.5 Mb. [ABSTRACT FROM AUTHOR]

Er3+/Yb3+ co-doped Na2O–CaF2–ZnO–Al2O3–SiO2 glasses with different Zn/Si ratios were prepared using the melt-quenching technique. The thermal stability was investigated by differential scanning calorimetry. Additionally, the absorption spectra were also analyzed to gather more information about their properties. The down-conversion luminescence corresponding to the strongest fluorescence at a wavelength of 547 nm was obtained under the 378 nm excitation, and a 4S3/2 level fluorescence lifetime was studied. By utilizing a laser pump with a wavelength of 980 nm, the process of both up-conversion and down-conversion luminescence was accomplished. In particular, the glasses substantially enhance fluorescence properties when the Zn/Si ratio is about 0.16. The changes in the Zn/Si ratio lead to modifications in the glass network structure, changing the coordination field environment around the fluorescence center and ultimately impacting the luminescence properties of the rare-earth ions. These effects are evidenced through the findings obtained from Fourier transform infrared spectroscopy and fluorescence spectroscopy analysis of the glass material. [ABSTRACT FROM AUTHOR]

Zn:Yb:Tm:LiNbO3 crystals with a range of [Li]/[Nb] ratios (0.94, 1.05, 1.20, and 1.38) were grown by Czochraski technique. The influence of [Li]/[Nb] ratio on the concentration of doped elements in grown crystal was investigated by inductively coupled plasma atomic emission spectrometry (ICP-AES). The defect structures formed at different [Li]/[Nb] ratios were studied by X-ray diffraction and INFRARED spectroscopy. The results show that, when the [Li]/[Nb] ratio increases, the segregation coefficients of Yb 3 + and Tm 3 + ions increase, while the segregation coefficient of Zn 2 + ions decreases. When the [Li]/[Nb] ratio in the melt increases to 1.20, the Zn:Yb:Tm:LiNbO3 crystal approaches the stoichiometric ratio. [ABSTRACT FROM AUTHOR]

The reactions of VOSO4·3H2O with Na2(cbdc) (cbdc2− – dianion of cyclobutane-1,1-dicarboxylic acid) and lanthanide(III) nitrates taken in a molar ratio of 1 : 2 : 1 were found to yield a series of isostructural heterometallic compounds [NaLn(VO)2(cbdc)4(H2O)10]n (1Ln, Ln = Tb, Dy, Ho, Er, Tm, Yb). These compounds are constructed from trinuclear anionic units [Ln(VO)2(cbdc)4(H2O)8]− ({LnV2}−) linked by Na+ ions into 1D polymeric chains. The crystal structures of 1Dy and 1Er were determined by single-crystal X-ray diffraction (XRD), and their isostructurality with 1Tb, 1Ho, 1Tm, and 1Yb was proved by powder X-ray diffraction (PXRD). According to alternating current (ac) magnetic susceptibility measurements, 1Dy, 1Er, and 1Yb exhibited field-induced slow relaxation of magnetization. Compound 1Er is the first representative of ErIII–VIV single-molecule magnets. Measuring the temperature dependences of the phase memory time (Tm) for 1Dy and 1Yb using pulsed EPR spectroscopy allowed us to observe the phenomenon of phase relaxation enhancement (PRE) at temperatures below 30 K. In future, this phenomenon may contribute to the evaluation of relaxation times of the lanthanide ions. [ABSTRACT FROM AUTHOR]

Ba 1.5 Sr 0.5 Zn 2 Fe 28-x Yb x O 46 (x = 0.00, 0.07, 0.14, 0.21, and 0.28) hexaferrite were synthesized via sol-gel auto-combustion route to investigate the microwave absorption performance in different frequency bands. The structure has a single phase, and the variation in lattice parameter was observed due to Yb-content as host iron Fe3+ and substituted Yb3+ having different ionic radii. Microwave absorbing materials (MAMs) need to be lightweight, and the maximum crystallite size of prepared material is 41 nm. The physical properties vary with substitution, and the X-ray density value is higher than the bulk density, and the porosity of the prepared sample increases when the bulk density decreases. Micro-strain values are inverse to the crystallite size because Yb3+ has larger ionic radii than Fe3+. Rietveld refinement of the XRD patterns was conducted with a lower significance value. FTIR bands observed between 414 and 500 cm−1 are present due to iron-oxygen bond stretching and bending vibrations at octahedral and tetrahedral lattice sites. The cation distribution is highly responsible for the peak position of octahedral and tetrahedral sites—the dielectric constant increases with frequency because of dipole, interfacial, and electronic/atomic polarization. AC conductivity is very low, reflecting that the material can be used as a dielectric medium in the microwave frequency range's L, S, and C bands. The best MAM among all prepared materials is Ba 1.5 Sr 0.5 Zn 2 Fe 27.72 Yb 0.28 O 46 which can be used for global positioning systems, weather radar, and satellite feeds as it has an excellent dielectric loss, remarkable tangential loss, and the reflection loss in P-, L-, S-, and C-bands. Other real-life application of all prepared materials are multi-layer chip inductor and longitudinal media recording. Flowchart: Step wise synthesis procedure. [Display omitted] [ABSTRACT FROM AUTHOR]

The 8.3 at.% Yb-doped yttrium-scandium-aluminum garnet (YSAG) ceramics were fabricated by a modified reverse co-precipitation method followed by uniaxial and cold isostatic pressing, annealing in air and high-temperature sintering in vacuum. Spectroscopic and lasing properties were investigated in dependence on Y/Sc/Al ratio in ceramic composition. Optical transmission of Yb:YSAG ceramics in visible and near-infrared spectral range exceeds 80 % that indicates a high quality of the Yb:YSAG samples. Among all the ceramics, the Y 2.35 Yb 0.25 Sc 1.00 Al 4.40 O 12 composition demonstrates the best lasing performance and the highest slope efficiency up to 75 %. [ABSTRACT FROM AUTHOR]

Lanthanides were tested (Ce3+, Er3+, and Yb3+) as catalysts to produce lactic acid (LA) from the monosaccharides present in corn stover (glucose, xylose, and arabinose) resulting in ytterbium being the most active. A MW-heated system led to similar LA yield as a conventionally heated pressurized system. The maximum value of LA yield was 40% at 240 °C after 20 min of isothermal treatment regardless the starting monosaccharides, which allowed to propose a similar LA production route based on the products profile determined along time for the three monosaccharides. Temperature and time determined the product profile, observing furfural degradation at severity factors higher than 3.5, while values higher than 5.5 were needed to observe LA degradation. By increasing temperature, catalyst solubility decreased, increasing its presence in the solid residue after treatment. Xylan conversion to LA was similar as for xylose, but lower yield was obtained from microcrystalline cellulose. Corn stover presented more amorphous regions leading to higher hydrolysis yields of its cellulose fraction. [ABSTRACT FROM AUTHOR]

Low thermal conductivities and high thermal expansion coefficients are desirable for rare-earth zirconate thermal barrier coating materials. Introduction of cation doping and adjustment of the nonstoichiometry are efficient methods for enhancing the thermophysical characteristics of materials. Herein, the thermophysical properties of Yb3+-doped nonstoichiometric gadolinium zirconate ceramic materials were investigated using first-principles calculations and solid-state reaction techniques. As the Yb3+ content increases, additional cations enter the interstitial spaces (for excess Gd3+ gadolinium zirconate) and form vacancy defects (for excess Zr4+ gadolinium zirconate), which serve as phonon scattering centres to decrease the thermal conductivity. When Yb3+ is doped at the same concentration, gadolinium zirconate with excess Zr4+ exhibits a lower thermal conductivity. Specifically, Gd 1.875 Yb 0.25 Zr 2.125 O 7 shows the lowest minimum thermal conductivity of 1.133 W/(m⸱K) (according to the Clark model) and 1.241 W/(m⸱K) (according to the Cahill model). In addition, the experimental results also suggest that the optimal content of Yb3+ is 0.25 excess Zr4+ gadolinium zirconate, which has the lowest intrinsic thermal conductivity of 1.037 W/(m⸱K) at 1300 K. Moreover, the thermal expansion coefficient of the Yb3+-doped excess Gd3+ nonstoichiometric material is greater than that of the doped excess Zr4+ material, this is due to the greater electronegativity difference between Yb3+ and Zr4+ than that between Yb3+ and Gd3+ and the lower binding energy of Gd-O than that of Zr-O. The experimental results and the calculated results are in good agreement. The aim of this work is to enhance the thermophysical characteristics of gadolinium zirconate ceramics for use as thermal barrier coating materials. [ABSTRACT FROM AUTHOR]

Rare earth ytterbium monosilicate (Yb 2 SiO 5) is one of the most ideal candidates for environmental barrier coatings. In this paper, Yb 2 SiO 5 coating was successfully fabricated by atmospheric plasma spraying technology. The effect of main gas flow rate and spraying powder composition on the microstructure and phase composition of Yb 2 SiO 5 coating were systematically investigated to solve the volatilization of SiO 2 during plasma-spraying process. The results showed that Yb 2 SiO 5 coating was relatively dense with the less internal defects under the main gas flow rate of 35 L/min, and the main gas flow rate from 30 L/min to 40 L/min had no significant effect on the melting effect of spraying powder and the porosity of coating. Yb 2 SiO 5 coating was composed of Yb 2 O 3 , Yb 2 SiO 5 two crystal phases and amorphous phase. The phase composition of coating was not affected by the change of main gas flow rate. After heat-treatment at 1400 °C for 20 h, Yb 2 SiO 5 crystal phase precipitated from the coating, and the content of Yb 2 SiO 5 phase reached 74.29 mol%, and the remaining phase was Yb 2 O 3 phase. The Yb 2 SiO 5 -25.71 mol% SiO 2 coating was still dense, the content of Yb 2 SiO 5 crystal phase was up to 97.76 mol% after heat-treatment, and the content of Yb 2 Si 2 O 7 phase was only 2.24 mol%, indicating that excessive addition of a certain amount of SiO 2 could compensate for the volatilization of SiO 2 , so as to prepare Yb 2 SiO 5 coating with approximate stoichiometric ratio. [ABSTRACT FROM AUTHOR]

In order to solve the increasingly serious electromagnetic wave pollution, the preparation of high-performance electromagnetic wave absorbing (EWA) materials has been very urgent. High-entropy ceramics have a good prospect in the field of EWA materials due to the unique effect brought by its multi-component elements. Therefore, in this study, the composition of high-entropy ceramics was designed by utilizing the Goldschmid tolerance factor. Then the high-entropy perovskite Ba(Zn 0.2 Yb 0.2 Ta 0.2 Nb 0.2 V 0.2)O 3 ceramic (BZO) with high EWA performance was prepared by high-temperature solid-phase method. The EWA mechanism of the material was explored based on the phase composition, microstructure and electromagnetic parameters of the samples. Good impedance matching and better attenuation ability were obtained for BZO-1100 due to the crystallographic transition and interface increase. As a result, BZO-1100 achieves excellent EWA performance at a thickness of 2.12 mm, with a minimum reflection loss (RL min) of −54.09 dB and an effective absorption bandwidth (EAB) of 2.81 GHz in the X-band. In addition, the possibility of the practical application of the BZO high-entropy ceramics is verified by electric field distribution simulations and RCS simulations. This study provides a valuable reference for the design of high-performance high-entropy perovskite ceramic absorber materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Mg-based amorphous alloys have broad applications due to disordered atomic structure, thermal stability, crystallinity, low elastic modulus and high strength. In the present study, Mg–Ni–Gd–Yb–Ag alloys were prepared by vacuum arc melting combined with copper roll melt spinning. The addition of trace amounts of ytterbium (Yb) improved the corrosion resistance of Mg73-XNi15Gd10YbXAg2 (x = 2,4,6,8 at.%). Electrochemical experiments, immersion tests and analysis of corrosion products by XPS and EDS showed that Mg67Ni15Gd10Yb6Ag2 exhibited the best corrosion resistance with an Ecorr of − 968 mV and an Icorr of 5.93 µA/cm2. The superior corrosion performance was attributed to the presence of corrosion passivation films comprising MgO, Mg(OH)2, Ni(OH)2, Ag2O, AgCl, Ca5(PO4)3(OH), as well as rare-earth oxides Gd2O3 and Yb2O3. These compounds efficiently shield the matrix, and the microstructure corrosion mechanism of Mg–Ni–Gd–Yb–Ag involves a cyclic process that includes surface film layer dissolution, matrix corrosion and film layer regeneration, leading to oxide attachment. The addition of the appropriate amount of rare-earth element Yb to Mg-based amorphous alloys can improve the corrosion resistance, thereby increasing the application prospects of alloys. [ABSTRACT FROM AUTHOR]

Consideration is given to the possibility of obtaining 177Lu radionuclide on the average flux research IRT-T nuclear reactor. The paper presents the results of simulating the neutron spectrum of the central channel CEC-1 of the IRT-T research reactor in the MCU program, calculations of the production of 177Lu from 176Yb2O3 in the CEC-1 neutron field and the dose rate from different radionuclides at a distance of 1 m and experiments on the production of 177Lu and its separation. The results of calculations and experiments are in agreement within an error of no more than 10% for 177Lu. The performed calculations and experiments have made it possible to carry out a preliminary assessment of the activity of 177Lu radionuclide, which can be obtained on the IRT-T research nuclear reactor, and also determine radiation protection required for working with radioactive ytterbium and lutetium. [ABSTRACT FROM AUTHOR]

The development direction of advanced solid-state lasers is higher output power and better beam quality. Rare earth ion doped yttrium aluminum garnet transparent ceramics are preferred materials for solid-state laser gain media, but thermal effects during the pumping process deteriorate the beam quality and hinder further increase in output power. The heat generation and dissipation of laser ceramics with complex configurations are more uniform during the pumping process, which can significantly reduce thermal effects. Compared with traditional preparation methods, 3D printing is able to form more complex design structures, suppress thermal effects, and achieve integration and miniaturisation of multi-module devices, driving lasers towards a wider range of applications. In this paper, several traditional methods for the preparation of laser ceramics with complex configurations are introduced firstly, and the advantages and limitations are analyzed. Then, the research status and problems in 3D printing yttrium aluminum garnet-based laser ceramics are systematically reviewed. Common 3D printing methods include direct ink writing, stereolithography, digital light processing, material jet printing, two-photon polymerization and micro-continuous liquid interface printing. Among them, there are interlayer defects in the samples printed by stereolithography and digital light processing, resulting in severe scattering losses. Material jetting printing combined with dry pressing can be used to manufacture planar waveguides. Two-photon polymerization and micro-continuous liquid interface printing are suitable for the fabrication of highly complex structures at micrometer scales. Direct ink writing not only enables the fabrication of laser ceramics for the first time, but also has the most extensive relevant research and is still the most promising method for the preparation of laser ceramics with complex configuration. At the end of this paper, the current problems and research prospects of yttrium aluminum garnet-based laser ceramics prepared by 3D printing are summarized. [ABSTRACT FROM AUTHOR]

Data-driven machine learning approaches with precise predictive capabilities are proposed to address the long-standing challenges in the calculation of complex many-electron atomic systems, including high computational costs and limited accuracy. In this work, we develop a general workflow for machine learning-assisted atomic structure calculations based on the Cowan code's Hartree–Fock with relativistic corrections (HFR) theory. The workflow incorporates enhanced ElasticNet and XGBoost algorithms, refined using entropy weight methodology to optimize performance. This semi-empirical framework is applied to calculate and analyze the excited state energy levels of the 4f closed-shell Yb I atom, providing insights into the applicability of different algorithms under various conditions. The reliability and advantages of this innovative approach are demonstrated through comprehensive comparisons with ab initio calculations, experimental data, and other theoretical results. [ABSTRACT FROM AUTHOR]

Alkaline basalts produced in continental arcs should contain information different from the arc tholeiite-calc-alkaline-series magmas, and their origin could provide unique constraints on deep mantle composition and material cycling. However, due to their sparse occurrence, alkaline basalts in continental arcs have not been studied thoroughly, which hinders our understanding of the mantle diversity and subduction dynamics under continental arcs. In this study, we present new 40Ar/39Ar ages, major and trace elements, and Sr-Nd-Hf isotopic data for the International Ocean Discovery Program Site U1504 alkaline basalts in the continental arc developed on the South China Block (SCB). These alkaline basalts were generated at ca. 121 Ma and display typical oceanic-island basalt geochemical characteristics. Their relatively high eNd(t) (3.5-3.7) and low (87Sr/86Sr)i (0.7034-0.7040) and La/Nb (0.5-1.0) values suggest that they were mainly derived from an asthenosphere mantle source. Compared to alkaline basalts in the SCB inland, U1504 alkaline basalts exhibit lower K2O/Na2O, Zr/Sm, Zr/Y, eNd(t), and eHf(t) values, indicating the addition of minor sub-continental lithospheric mantle. The enrichment of Nb, Ta, light rare earth elements, and slight depletion of Zr, Hf, and Ti, as well as elevated Fe/Mn and Sm/Yb and low CaO, indicate that their mantle lithology was mainly garnet pyroxenite. Based upon these findings and previous studies, the garnet pyroxenite was probably formed by the interaction of upwelling asthenosphere with slab edges in the scenario of break-off of the Paleo-Pacific Plate, and such interaction diversified the mantle chemistry beneath continental arcs. In conjunction with other reported alkaline basalt data, it is proposed that the enriched asthenosphere mantle beneath the SCB had formed sequentially from inland to coastal since the late Mesozoic, and this may be related to lateral and vertical flow in the deep asthenosphere controlled by the break-off of subducted plates. [ABSTRACT FROM AUTHOR]

LuAG-based optical ceramics co-doped with Yb3+ and Er3+ ions was successfully synthesized for the first time. The optical, spectral-luminescent, and kinetic characteristics of ceramics based on Y2.82Yb0.15Er0.03Al5O12 (YAG 5-Yb, 1-Er) and Lu2.82Yb0.15Er0.03Al5O12 (LuAG 5-Yb, 1-Er) compositions were investigated. It is demonstrated that excitation of luminescence at a wavelength of 940 nm in YAG 5-Yb, 1-Er and LuAG 5-Yb, 1-Er ceramics results in the effective transfer of excitation radiation energy from Yb3+ ions to Er3+ ions. The energy transitions that play a pivotal role in the processes of Stokes and anti-Stokes luminescence of ceramics based on YAG 5-Yb, 1-Er and LuAG 5-Yb compositions was identified, and a schematic representation of these transitions is presented. The mutual variation of the intensity of anti-Stokes luminescence bands resulting from the transitions 2H11/2 → 4I15/2 (525 nm) and 4S3/2 →4I15/2 (546 nm) was observed, with regard to the power of the excitation radiation. This study demonstrates the potential of YAG 5-Yb, 1-Er and LuAG 5-Yb, 1-Er ceramics as materials for optical thermometry. [ABSTRACT FROM AUTHOR]

Ytterbium silicate (Yb2Si2O7) and lanthanum zirconate (La2Zr2O7) ceramic powders were synthesized by the sol–gel method. A novel tri‐layer La2Zr2O7/Yb2Si2O7/SiC environmental barrier coating was prepared on the surface of C/SiC composites to improve the service temperature of the coating (above the Si melting point, 1683 K). Results show that both Yb2Si2O7 and La2Zr2O7 ceramic powders had extremely high purity and were accompanied by a large number of nanoparticles. The tri‐layer La2Zr2O7/Yb2Si2O7/SiC coating can efficiently prevent the oxidation failure of C/SiC composites in 1773 K air environment for more than 100 h with slight weight loss of 5.71 × 10−3 g·cm−2 and the matching weight loss rate of 5.71 × 10−5 g·cm−2·h−1. No significant chemical reaction was observed between Yb2Si2O7 middle and La2Zr2O7 outer coatings during the oxidation process at 1773 K, indicating that the tri‐layer La2Zr2O7/Yb2Si2O7/SiC coating had better oxidation stability in 1773 K air environment. [ABSTRACT FROM AUTHOR]

[Display omitted] • The design of active and inert shell in NaYF 4 :Yb,Er @ NaYF 4 UCNPs exhibits the superior luminescence under 980 nm excitation. • NaYF 4 @NaYF 4 :Yb,Nd,Er core–shell UCNPs demonstrate optimized luminescence under 808 nm laser excitation because the inert core can bring the activators into closer proximity with each other. • NaYbF 4 as an active layer improves temperature sensitivity with S r = 1.12 %K−1 under 808 nm excitation. Research on the core–shell design of rare earth-doped nanoparticles has recently gained significant attention, particularly in exploring the synergistic effects of combining active and inert shell layers. In this study, we successfully synthesized 8 types of spherical core–shell Na-based nanoparticles to enhance the efficiency of core–shell design in upconversion luminescence and temperature sensing through the strategic arrangement of inert and active layers. The most effective upconversion luminescence was observed under 980 nm and 808 nm laser excitation using NaYF 4 inert shell NaYF 4 :Yb3+, Er3+@ NaYF 4 and NaYF 4 @ NaYF4:Yb3+, Nd3+ core–shell nanostructures. Moreover, the incorporation of the NaYbF 4 active shell structure led to a significant increase in relative sensitivity in ratio luminescence thermometry. Notably, the NaYF 4 :Yb3+, Nd3+, Er3+@ NaYbF 4 core–shell structure demonstrated the highest relative sensitivity of 1.12 %K−1. This research underscores the crucial role of inert shell layers in enhancing upconversion luminescence in core–shell structure design, while active layers play a key role in achieving high-sensitivity temperature detection capabilities. [ABSTRACT FROM AUTHOR]

Fluorescence intensity ratio (FIR) technology is compulsorily needed in non-contact rare-earth luminescent temperature sensors. Here, we present Er/Yb:Y3Al5O12 phosphors synthesized via a high-temperature solid-state reaction method. The crystal structure, microstructure, up-conversion luminescence, and energy transfer between the two ions have been comprehensively analyzed. Under 980-nm excitation, the samples exhibited four distinct transition bands at 475 nm, 525 nm, 546 nm, and 664 nm. The quantum efficiency reached 12.14%. Utilizing the thermally coupled level of I525/I546 as a basis for analysis yields a maximum relative sensitivity of 1.05% K−1. We observed that the spectral color coordinates varied linearly with temperature within a specific range, suggesting its potential application as a means of temperature measurement. Furthermore, employing the non-thermally coupled levels of I546/I475 for temperature measurement results in an impressive maximum absolute sensitivity of 8.05% K−1, nearly 24 times higher than that achieved through thermally coupled levels alone. The temperature resolution of the synthetic material is basically less than 0.3 K with high thermal stability. Therefore, Er/Yb:Y3Al5O12 phosphors hold promise as viable candidates for components in temperature-sensor applications. [ABSTRACT FROM AUTHOR]

LuAG-based optical ceramics co-doped with Yb3+ and Er3+ ions was successfully synthesized for the first time. The optical, spectral-luminescent, and kinetic characteristics of ceramics based on Y2.82Yb0.15Er0.03Al5O12 (YAG 5-Yb, 1-Er) and Lu2.82Yb0.15Er0.03Al5O12 (LuAG 5-Yb, 1-Er) compositions were investigated. It is demonstrated that excitation of luminescence at a wavelength of 940 nm in YAG 5-Yb, 1-Er and LuAG 5-Yb, 1-Er ceramics results in the effective transfer of excitation radiation energy from Yb3+ ions to Er3+ ions. The energy transitions that play a pivotal role in the processes of Stokes and anti-Stokes luminescence of ceramics based on YAG 5-Yb, 1-Er and LuAG 5-Yb compositions was identified, and a schematic representation of these transitions is presented. The mutual variation of the intensity of anti-Stokes luminescence bands resulting from the transitions 2H11/2 → 4I15/2 (525 nm) and 4S3/2 →4I15/2 (546 nm) was observed, with regard to the power of the excitation radiation. This study demonstrates the potential of YAG 5-Yb, 1-Er and LuAG 5-Yb, 1-Er ceramics as materials for optical thermometry. [ABSTRACT FROM AUTHOR]

Near-infrared (NIR)-emitting phosphors with broadband absorption from ultraviolet to visible light have been considered significant spectral converter materials for solar cells. In this work, NIR phosphor Zn3Ga2GeO8 (ZGGO):Cr3+,Yb3+ spinel solid solutions were synthesized using the classical high-temperature solid-state method. With an increase in the doping concentration of Cr3+ ions in ZGGO:Cr3+,Yb3+, a more distorted octahedron appeared around Cr3+ ions, which increased crystal field splitting. This process was accompanied with a broadening of NIR emission from Cr3+ 4T2 → 4A2 transition and enlarged the overlap area between the absorption spectrum of Yb3+ and the emission spectrum of Cr3+, resulting in an efficient energy transfer between Cr3+ and Yb3+. In the case of high-concentration Cr3+ doping, the near-infrared luminescence intensity of Yb3+ was more than 8 times that of low-concentration doped Cr3+. Therefore, it is proposed that the Cr3+,Yb3+ co-doped ZGGO phosphor is a potential spectral convert materials for silicon-based solar cells and thereby improves photovoltaic conversion efficiency. [ABSTRACT FROM AUTHOR]

Cubic and hexagonal structured SrTa4O11(STO):Er3+/Yb3+ phosphors were synthesized by a solid state reaction (SSR) and molten salt synthesis (MSS). The upconversion luminescence (UCL) intensity of these samples was investigated. Hexagonal STO:Er3+/Yb3+ with much or a little β-Ta2O5 can be synthesized by SSR in air or vacuum, respectively, and the UCL intensity of the sample synthesized by SSR in a vacuum is higher. Cubic STO:Er3+/Yb3+ can be synthesized by MSS with KCl flux, and hexagonal STO:Er3+/Yb3+ can be synthesized by MSS with B2O3 flux, which has the strongest UCL intensity among all the samples compared with samples prepared by SSR. The sample by MSS with B2O3 flux was acid pickled (AP) with HCl solution, and the green UCL intensity increased by 2.18 times, which reached 32.95% for β-NaYF4:Er3+/Yb3+. The UCL intensity of the hexagonal STO:Er3+/Yb3+ is much higher than that of the cubic structure, which is due to the layered structure and the non-central symmetry of the Er3+/Yb3+ doped sites in hexagonal STO:Er3+/Yb3+. The temperature sensitivity of samples is evaluated by luminescence intensity ratio (LIR) technology. The maximum relative sensitivity is 0.0099 K−1 at 303 K. All the results show that hexagonal STO:Er3+/Yb3+ has excellent pure green UCL intensity and high temperature sensitivity, which can be used in UCL display and temperature sensing. [ABSTRACT FROM AUTHOR]

For reliable long-term operation of solid oxide electrochemical devices for the hydrogen energy system, an electrolyte with high ionic conductivity and excellent chemical stability is required. SrHfO 3 -based perovskites are known for their high chemical resistance; however, their ionic conductivity must be increased. In the present research, the effect of doping with yttrium and ytterbium on the electrical properties of strontium hafnate was studied for the first time. The crystal structure, solubility limit of the dopants, morphology and electrical properties of SrHf 1-x M x O 3-δ (M = Y, Yb) materials were investigated by the X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, direct current four-probe technique, and impedance spectroscopy. The solubility limits of Y and Yb in SrHfO 3 were found to lie slightly below x = 0.10. It was revealed that yttrium doping is more favorable for the grain growth and densification of ceramics. A comparative analysis of the influence of dopant type (Y, Yb and Sc) and concentration on the electrical properties of SrHfO 3 is provided. [Display omitted] • Homogeneity range of SrHf 1-x Y x O 3-δ and SrHf 1-x Yb x O 3-δ solid solutions extends to x ≈< 0.10. • Y-doping is more favorable for the grain growth and densification of ceramics. • Y and Yb-doping enhance proton conductivity of SrHfO 3. • Y-doped SrHfO 3 has higher ionic transference numbers in wet oxidizing atmospheres. [ABSTRACT FROM AUTHOR]

Near-infrared (NIR)-emitting phosphors with broadband absorption from ultraviolet to visible light have been considered significant spectral converter materials for solar cells. In this work, NIR phosphor Zn3Ga2GeO8 (ZGGO):Cr3+,Yb3+ spinel solid solutions were synthesized using the classical high-temperature solid-state method. With an increase in the doping concentration of Cr3+ ions in ZGGO:Cr3+,Yb3+, a more distorted octahedron appeared around Cr3+ ions, which increased crystal field splitting. This process was accompanied with a broadening of NIR emission from Cr3+ 4T2 → 4A2 transition and enlarged the overlap area between the absorption spectrum of Yb3+ and the emission spectrum of Cr3+, resulting in an efficient energy transfer between Cr3+ and Yb3+. In the case of high-concentration Cr3+ doping, the near-infrared luminescence intensity of Yb3+ was more than 8 times that of low-concentration doped Cr3+. Therefore, it is proposed that the Cr3+,Yb3+ co-doped ZGGO phosphor is a potential spectral convert materials for silicon-based solar cells and thereby improves photovoltaic conversion efficiency. [ABSTRACT FROM AUTHOR]

Excitation wavelength controllable lanthanide upconversion allows for real-time manipulation of luminescent color in a composition-fixed material, which has been proven to be conducive to a variety of applications, such as optical anti-counterfeiting and information security. However, current available materials highly rely on the elaborate core–shell structure in order to ensure efficient excitation-dependent energy transfer routes. Herein, multicolor upconversion luminescence in response to both near-infrared I and near-infrared II (NIR-I and NIR-II) excitations is realized in a novel but simple NaYGeO4:Yb3+/Er3+ phosphor. The remarkably enhanced red emission ratio under 1532 nm excitation, compared with that under 980 nm excitation, could be attributed to the Yb3+-mediated cross-relaxation energy transfers. Moreover, multi-wavelength excitable temperature-dependent (295–823 K) upconversion luminescence realizes a ratiometric thermometry relying on the thermally coupled levels (TCLs) of Er3+. Detailed investigations demonstrate that changing excitation wavelength makes little difference for the performances of TCL-based ratiometric thermometry of NaYGeO4:Yb3+/Er3+. These findings gain more insights to manipulate cross-relaxations for excitation controllable upconversion in single activator doped materials and benefit the cognition of the effect of excitation wavelength on ratiometric luminescence thermometry. [ABSTRACT FROM AUTHOR]

The bulky monodentate carbazolyl ligand 1,8-bis(3,5-ditertbutylphenyl)-3,6-ditertbutylcarbazole (dtbpCbz) was employed in the synthesis of monomeric heteroleptic amido carbazolyl complexes of Ca and Yb. For both central metal atoms, dimeric hydride complexes [(dtbpCbz)Ca(benzene)H]2, [(dtbpCbz)Ca(THF)H]2, [(dtbpCbz)Yb(benzene)H]2 and [(dtbpCbz)Yb(THF)H]2 were obtained, which show remarkably poor solubility in organic solvents. The characteristic hydride 1H NMR resonance of [(dtbpCbz)Ca(benzene)H]2 was observed at 2.07 ppm, and for the first time, characteristic vibrational modes of the Ca2H2 and Yb2H2 moiety are discussed. Despite their poor solubility, the hydride complexes could be reacted with CO to yield the corresponding ethenediolate complexes. [ABSTRACT FROM AUTHOR]

Y 2 O 3 : 5%Yb3+, 0.5%Tm3+, z%Ho3+ (z = 0, 0.1, 0.5, 1.0) upconversion luminescent materials were synthesized by CO 2 laser zone melting method. The upconversion luminescence (UCL) spectra of the samples were recorded with the excitation of 980 nm laser, and the energy transfer processes among doped rare earth (RE) ions were analyzed. The introduction of Ho3+ ions into Y 2 O 3 : 5%Yb3+, 0.5%Tm3+ gave the samples four distinct UCL bands, including blue, green, red, and infrared emission bands. The temperature sensing characteristics based on the fluorescence intensity ratio (FIR) of non-thermally coupled levels (NTCLs) of Tm3+ and Ho3+ ions were studied, and the derived maximum relative sensitivity (S R) reached impressive value of 0.0138 K-1 (298 K). Compared to the materials doped with single emission center of either Tm3+ or Ho3+ ions, the luminescent material co-doped with both Tm3+ and Ho3+ ions exhibited higher sensitivity while maintaining a wide temperature measurement range. The research results indicate that Y 2 O 3 : Yb3+, Tm3+, Ho3+ upconversion phosphor promises broad application prospects in optical temperature measurement. [ABSTRACT FROM AUTHOR]

Thermal barrier coating (TBC) is applied to protect the hot-section components of a gas turbine engine. In the present work, a La2(Zr0.2Ti0.2Y0.2YB0.2Nb0.2)2O7 high entropy oxide was designed, fabricated by a solid-phase reaction at 1400 °C, and subjected to an investigation of its properties. The results indicate that the La2(Zr0.2Ti0.2Yb0.2Y0.2Nb0.2)2O7 high entropy oxide had a pyrochlore structure. During synthesis, a small amount of La2TiO5 was produced. The thermal conductivity of the La2(Zr0.2Ti0.2Yb0.2Y0.2Nb0.2)2O7 high entropy oxide was approximately 0.8855 W·m-1·K-1 at room temperature. The coefficient of thermal expansion of the La2(Zr0.2Ti0.2Yb0.2Y0.2Nb0.2)2O7 high entropy oxide was approximately 9.374 × 10−6 K−1 at 1000 °C. To improve the service life of the TBC composed of the La2(Zr0.2Ti0.2Yb0.2Y0.2Nb0.2)2O7, a double-layer structural coating composed of La2(Zr0.2Ti0.2Y0.2YB0.2Nb0.2)2O7 and yttria-stabilized zirconia (YSZ) layers was designed and produced on a NiCoCrAlY alloy by laser cladding. The thermal cycling behavior of the double-layer coating was studied at 1050 °C. The results indicate that a La2(Zr0.2Ti0.2Yb0.2Y0.2Nb0.2)2O7 single-phase defective-fluorite high entropy oxide was produced after preparation and thermal cycling. The spallation of the double-layer coating composed of La2(Zr0.2Ti0.2Yb0.2Y0.2Nb0.2)2O7/YSZ occurred after 70 thermal cycles at 1050 °C. The double-layer coating composed of La2(Zr0.2Ti0.2Yb0.2Y0.2Nb0.2)2O7/YSZ can increase the thermal cycling lifetime of TBCs containing high entropy oxides. [ABSTRACT FROM AUTHOR]

The characteristics of silicon MIS structures with ytterbium impurity are studied using non-stationary capacitance spectroscopy of deep levels. It is established that the presence of ytterbium atoms in the bulk of the silicon substrate leads to a shift in the capacitance-voltage characteristics towards positive bias voltages and a decrease in the density Nss of the surface states of the MIS structures. It is shown that this effect depends on the concentration of ytterbium atoms in the silicon substrate of the studied structures. In MIS structures based on Si, one deep level with an ionization energy Ec-0.32 eV is detected. [ABSTRACT FROM AUTHOR]

In this paper, a Wide tunble in C + L band single-wavelength passively Q-switched fiber laser (PQFL) consisting of cascaded doped fiber segments and a tunable band-pass filter (TBF) is proposed. The TBF achieves precise tuning of the wavelength with a maximum tunable range of 45.04 nm (1529.08–1574.12 nm). When the fiber is non-completely pumped, erbium-doped fiber (EDF) and erbium-ytterbium co-doped fiber (EYDF) act as saturable absorbers (SA). It has different nonlinearities under different pump power combinations, producing passively Q-switched pulses with repetition frequencies from 8.23 kHz to 46.47 kHz and pulse widths reduced from 12.82 μs to 2.00 μs. In addition, the wavelength range of passively Q-switched is also changing from 11.55 nm to 31.04 nm. In the experiment, the change in the wavelength range of the passively Q-switched pulse was explained by analyzing the gain saturation absorption characteristics of the EDF and the EYDF. In the experiment, only four devices are used to achieve single-wavelength wide tuning and passively Q-switched, which is enough to prove the simplicity and compactness of the structure. The proposed FQFL has broad application prospects in the fields of distributed sensing systems and bio-medical imaging. [ABSTRACT FROM AUTHOR]

BaGeTeO6: Nd3+/Yb3+/Ho3+ green up-conversion phosphors were synthesized using the high-temperature solid-state reaction method. The optimal doping concentrations for the three dopant ions Nd3+, Yb3+, and Ho3+ were determined to be 1 mol%, 6 mol%, and 0.8 mol%, respectively, through the method of controlling variables. By analyzing the dependence of the up-conversion luminescence intensity on the pump current of the 980 nm laser, it was found that the green and red up-conversion emissions of Ho3+ ions under 980 nm laser excitation were both two-photon processes. Furthermore, the influence of temperature on the up-conversion luminescent properties of BaGeTeO6: Nd3+/Yb3+/Ho3+ green up-conversion phosphors under 980 nm laser excitation was investigated, and the temperature sensing properties of Ho3+ ions were discussed. The results indicated that, at room temperature and higher temperatures, both the red and green up-conversion emissions of the sample were two-photon processes. Within the range of excitation current used in the experiment, the ratio of red to green up-conversion luminescence intensity of Ho3+ ions was independent of the laser excitation current but correlated with the sample temperature. In the temperature range of 303–723 K, the ratio of red to green up-conversion luminescence intensity of Ho3+ ions exhibited a nonlinear relationship with temperature. Comparing the temperature sensing sensitivity of Ho3+ in different matrices, the results indicated that the sample possessed high temperature sensing sensitivity. [ABSTRACT FROM AUTHOR]

Bulk samples of holmium and ytterbium rare earth titanates doped with yttrium and bismuth were synthesized. To study the magnetic properties and peculiarities of magnetic interaction in doped and undoped titanates, magnetization curves and temperature dependences of the susceptibility were measured in fields up to 3 T at temperatures from 2 to 300 K. Magnetic properties for doped and undoped titanates with different doping level, as well as doped with different elements, have been compared. Based on study of temperature dependences of the susceptibility, magnetic dipole and exchange interactions have been analyzed. In the case of undoped holmium titanate, the dominant magnetic interaction type has been found to be the dipole one. When doping of holmium titanate with yttrium and bismuth, the magnetic interactions between the rare earth ions are sharply weak. Undoped ytterbium titanates have shown a predominance of the superexchange interaction. Presence of a large number of randomly distributed yttrium or bismuth ions, which occupy positions of ytterbium ions in crystal lattice, leads to the decrease in concentration of R3+-O-R3+ ion pairs in this rare earth titanate, between which there is superexchange. Therefore, in doped compounds, the magnetic dipole interaction capable to act at large distances contrary to the superexchange one begins to predominate. The values of the g-factor have been estimated by the fit of the measured magnetization curves. [ABSTRACT FROM AUTHOR]

The exploration of photon avalanching (PA) luminescence in different lanthanide emitters has profound implications in plentiful frontier applications. However, studies for universal mechanisms at the nanoscale to exhibit giant nonlinear responses in various avalanching emitters are limited. Here, record‐breaking nonlinear responses up to 60th‐order in high‐lying emitting levels of various emitters at room temperature are generated by proposing a universal mechanism named energy relay‐mediated photon avalanche (enrePA). By harnessing energy from the avalanching nano‐engine through the energy relay of Yb3+ ions, the brightness of blue emissions from Tm3+ and Ho3+ can be enhanced with giant optical nonlinearity up to 60th and 38th order, respectively. Further incorporating gadolinium‐based systems, more emitters (Tb3+, Eu3+, Dy3+, Nd3+) can be activated with extreme optical nonlinearities up to 48th‐order. By expanding PA into the full‐spectrum range, the enrePA mechanism opens exciting avenues for flexible and high‐efficiency PA modulation in multilayer nanostructures, enabling the applicability of PA in more technologies such as super‐resolution imaging, lithography, and optical detection. [ABSTRACT FROM AUTHOR]

Optical ceramics with 50 at.% Sc in both dodecahedral ({Y 1·17 Er 0.03 Yb 0.3 Sc 1.5 }[Al 1.8 Sc 0.2 ]Al 3 O 12 , {Y 1.2 Yb 0.3 Sc 1.5 }[Al 1.8 Sc 0.2 ]Al 3 O 12) and octahedral ({Y 2·52 Er 0.03 Yb 0.3 Sc 0.15 }[Al 1.0 Sc 1.0 ]Al 3 O 12 , {Y 2.55 Yb 0.3 Sc 0.15 }[Al 1.0 Sc 1.0 ]Al 3 O 12) sites of the garnet structure were synthesized using the non-reactive vacuum sintering method. Analysis of the phase composition, thermal diffusivity, transmission in the visible and IR regions of the spectrum, as well as luminescent properties (Stokes and anti-Stokes luminescence, luminescence decay kinetics) revealed clear correlations with the chemical composition of ceramics. It has been determined that solid solutions in which Y3+ cations are partially replaced by Sc3+ cations, compared to solid solutions in which Al3+ cations in the octahedral site are partially replaced by Sc3+, are characterized by lower crystal lattice parameters (11.883 ± 0.004 Å and 12.153 ± 0.005 Å); lower thermal conductivity values (4.72 W/(m·K) and 5.9 W/(m·K)); higher characteristic vibration frequencies of structural groups; shorter lifetimes of excited states of Yb3+ (1.41 μs and 1.56 μs for YSAG:Yb; 0.42 μs and 0.65 μs for YSAG:Yb,Er) and Er3+ (8.6 μs and 9.2 μs) cations; higher efficiency of energy transfer from Yb3+ to Er3+. The results clearly indicate that solid solutions with high concentrations of Sc3+ cations in the dodecahedral site can also be effective matrices for Yb3+ and Er3+ cations compared to solid solutions with a predominant introduction of scandium in the octahedral site. [ABSTRACT FROM AUTHOR]

Yttrium barium copper oxide (YBCO) is used for special applications in linear generators because of its excitation loss, lower weight, and higher efficiency. These qualities enable the compound to operate better than the conventional copper wire coil in the stator unit of the linear generator. However, the continuous use of YBCO in linear generators has a fundamental challenge that affects industrial production and material stability after prolonged use. This paper seeks to sustain the adoption of YBCO by improving its quality for linear generator applications. The yttrium cuprates modification (YBYbCO) was synthesized using the solid-state reaction technique by doping YBCO with ytterbium. The crystalline structure, microstructural pattern, and stability of the new sample were adequately measured and found to be structurally stable to ensure durability. It was reported that applying YBYbCO in the linear generator would lead to a 200% increase in energy generation. The higher number of particles and lower individual particulate resistance enable it to withstand chemical pressure, thereby prolonging the lifespan of the linear generator. [ABSTRACT FROM AUTHOR]

The lanthanide series elements are transition metals used as critical components of electronics, as well as rechargeable batteries, fertilizers, antimicrobials, contrast agents for medical imaging, and diesel fuel additives. With the surge in their utilization, lanthanide metals are being found more in our environment. However, little is known about the health effects associated with lanthanide exposure. Epidemiological studies as well as studies performed in rodents exposed to lanthanum (La) suggest neurological damage, learning and memory impairment, and disruption of neurotransmitter signaling, particularly in serotonin and dopamine pathways. Unfortunately, little is known about the neurological effects of heavier lanthanides. As dysfunctions of serotonergic and dopaminergic signaling are implicated in multiple neurological conditions, including Parkinson's disease, depression, generalized anxiety disorder, and post-traumatic stress disorder, it is of utmost importance to determine the effects of La and other lanthanides on these neurotransmitter systems. We therefore hypothesized that early-life exposure of light [La (III) or cerium (Ce (III))] or heavy [erbium (Er (III)) or ytterbium (Yb (III))] lanthanides in Caenorhabditis elegans could cause dysregulation of serotonergic and dopaminergic signaling upon adulthood. Serotonergic signaling was assessed by measuring pharyngeal pump rate, crawl-to-swim transition, as well as egg-laying behaviors. Dopaminergic signaling was assessed by measuring locomotor rate and egg-laying and swim-to-crawl transition behaviors. Treatment with La (III), Ce (III), Er (III), or Yb (III) caused deficits in serotonergic or dopaminergic signaling in all assays, suggesting both the heavy and light lanthanides disrupt these neurotransmitter systems. Concomitant with dysregulation of neurotransmission, all four lanthanides increased reactive oxygen species (ROS) generation and decreased glutathione and ATP levels. This suggests increased oxidative stress, which is a known modifier of neurotransmission. Altogether, our data suggest that both heavy and light lanthanide series elements disrupt serotonergic and dopaminergic signaling and may affect the development or pharmacological management of related neurological conditions. [ABSTRACT FROM AUTHOR]

Efficient removal of oxygen (O) impurities from titanium (Ti) scrap is necessary to accelerate the recycling of Ti scrap. However, deoxidation of Ti is extremely difficult, both thermodynamically and technically. In this study, we developed a deoxidation technique that uses Yb (a rare earth metal with high vapor pressure at elevated temperatures) to directly remove O dissolved in solid Ti. Experimental results showed that deoxidation using Yb in halide salt fluxes such as LiCl and LiF produced Ti with O concentrations of 520-1400 mass ppm. The O concentration in deoxidized Ti samples was reduced to a level lower than that in Ti under the Yb/Yb2O3 equilibrium, probably owing to the decrease in the activity of Yb2O3, which was the deoxidation product, caused by its dissolution in the fluxes. In contrast, when vapor of Yb metal and halide salts were supplied to Ti samples via a gas phase, the Ti samples were deoxidized to the same O concentration as that under the Yb/Yb2O3 equilibrium. This deoxidation limit was controlled by the Yb/Yb2O3 equilibrium. The supply of halide salt vapor did not affect the deoxidation limit. The proposed deoxidation method is expected to help scale up the recycling of Ti scrap and ensure efficient utilization of resources.

The application of rare earth (RE) doped crystals in quantum information processing has attracted more and more attention in the past decade. How to change the clock transitions of RE ion in crystal and control their lifetime of maintaining coherent quantum state is a valuable question. In this work, the trigonal 171Yb3+ centers in lithium niobate (LN) crystal are investigated theoretically to obtain their accurate ground and excited hyperfine sublevels under external magnetic field B by a combined method of density functional theory-based geometric optimization and parametric effective Hamiltonian modeling. An optical clock transition at |B| = 45.73 mT along the c axis of the LN crystal is successfully found by calculation. To show the pressure-dependent behavior of optical clock transition, the variation of such transition under hydrostatic pressure up to 3 GPa is also obtained theoretically. The calculated results show that applying external pressure is an effective way to control these transitions of RE ion doped crystal. Moreover, the optical coherence time T2 at zero magnetic field for 171Yb3+ ion with C3 symmetry in the LN crystal is estimated by our calculations. The calculated results indicate that if the magnetic field noise is 33 μT in the LN crystal, it is possible to find an optical clock transition with long coherence time T2 (≈382 μs) at the zero magnetic field. The present methods of seeking optical clock transition and calculating its coherence time T2 caused by a fluctuating magnetic field noise in the host crystal can be applied to other Kramers RE ions doped materials. [ABSTRACT FROM AUTHOR]

Luminescence thermometry is the most versatile remote temperature sensing technique and can be employed from living cells to large surfaces and from cryogenic temperatures to the melting points of metals. Ongoing research aims to optimize the sensitivity of the ratio between the emission intensity from two coupled excited states. However, this approach is inherently limited to temperature-dependent processes involving only the excited states. Here, we develop a novel measurement technique, called luminescence intensity ratio squared (LIR2) for the Yb3+/Er3+ pair, that combines the temperature sensitivity of ground- and excited-state populations. We use Y3Al5O12:Er3+,Yb3+ nanoparticles as a promising model system with both visible and infrared emissions. To apply our method, we record two luminescence spectra at different excitation wavelengths and determine the LIR2 using one emission in each of the two spectra. The LIR2 testing with Y3Al5O12 nanoparticles showed a sensitivity increase of 70% in the visible region and an impressive 230% increase in the NIR region compared to the conventional LIR method. This enhances the measurement precision by a factor of 1.5–2.5. The LIR2 based on the visible upconversion emission is particularly useful for measurements of high temperatures, while the LIR2 based on the downshifted ∼1.5 μm emission may revolutionize temperature measurements of biological samples in the range of physiological temperatures. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen production with simultaneous degradation of organic pollutants by using solar energy provide a promising strategy to solve the energy and environmental issue in the future. However, for onefold wide band-gap semiconductor, the poor photocatalytic efficiency limits its application on a large scale due to its easy recombination of photo-generated electron-hole pairs and low solar energy utilization. Herein, a novel Z-scheme BiVO 4 (040)-Bi-(NaYF 4 :Er,Yb,Tm@BiOBr)/Bi photocatalyst is prepared via photo-assisted isoelectric point method. In this composite photocatalyst, up-convention luminescence material, NaYF 4 :Er,Yb,Tm, can offer more ultraviolet light and visible light to intensify the activations of BiOBr and metal Bi nanoparticles, respectively. Furthermore, the formation of Z-scheme BiVO 4 (040)-BiOBr photocatalystic sytem, the spatial separation of the BiVO 4 (040) and BiVO 4 (110) facets and the presence of metal Bi surface plasmon resonance effect are contributed to the high-efficiency separation of the photo-generated electron-hole pairs. The experimental results show that as-prepared Z-scheme BiVO 4 (040)-Bi-(NaYF 4 :Er,Yb,Tm@BiOBr)/Bi photocatalyst exhibits advanced photocatalytic hydrogen production amount (192.0 μm) and excellent degradation ratio of malachite green (88.51 %) under simulated sunlight irradiation for 5.0 h. The apparent quantum yield of the Z-scheme BiVO 4 (040)-Bi-(NaYF 4 :Er,Yb,Tm@BiOBr)/Bi photocatalyst at 420 nm reaches a specific value of 5.8 %. In addition, Z-scheme BiVO 4 (040)-Bi-(NaYF 4 :Er,Yb,Tm@BiOBr)/Bi photocatalyst also remains a high stability in the photocatalytic hydrogen production with simultaneous degradation of malachite green within six reuse. At last, the possible reaction mechanism and degradation pathways of malachite green caused by Z-scheme BiVO 4 (040)-Bi-(NaYF 4 :Er,Yb,Tm@BiOBr)/Bi photocatalyst under simulated sunlight irradiation are put forward. • A high-efficiency BiVO 4 (040)-Bi-(NaYF 4 :Er,Yb,Tm@BiOBr)/Bi photocatalyst is prepared. • NaYF 4 :Er,Yb,Tm offers UV and VS lights to intensify activations of BiOBr and Bi. • The occurrence of SPR effect of Bi nanoparticles inhibits e− and h+ recombination. • BiVO 4 achieves the separation of photo-induced carrier on the (040) and (110) facet. • Malachite green is used as sacrifice agent for enhancing photocatalytic H 2 evolution. [ABSTRACT FROM AUTHOR]

Er3+/Yb3+ doped YVO4 and GdVO4 phosphors were prepared through the combustion technique and were characterized through various techniques. XRD has revealed a tetragonal structure for YVO4 and GdVO4 phosphors. The 980 nm excited upconversion emission has resulted in intense green upconversion emission from both samples. However, the GdVO4 sample has shown higher emission intensity. Photoacoustic heat generation in samples has been studied using the same 980 nm excitation, and in this case, the YVO4 phosphor has shown higher heat generation. The YVO4 phosphor again has shown lower heat dissipation and, hence, higher photo-thermal conversion efficiency upon irradiation of the sample. [ABSTRACT FROM AUTHOR]

Abradable environmental barrier coatings (EBCs) are used to reduce clearances between blades and casings in the hottest parts of aero gas turbines, increasing the overall efficiency of the turbine, however, research into the mechanical performance of such coatings is limited. The aim of this work was to better understand the relationship between microstructure and erosion and wear performance in abradable EBCs, since publicly available literature regarding such coatings is scarce and the potential efficiency gains in gas turbines are significant. In this study, ytterbium disilicate abradable EBCs containing three different porosity levels (determined by fugitive polyester phase addition) were deposited using atmospheric plasma spraying with porosity levels of 8, 15 and 21.5% by area. These coatings were then characterised in numerous ways; the porosity was quantified, the thermal conductivity was measured, the superficial hardness and erosion resistance were measured, and finally, the coatings were subjected to a rig test designed to simulate in-service cutting mechanisms against a tipped turbine blade. The results show that increasing the level of porosity via increasing the amount of pore forming phase in the feedstock, led to reduced erosion resistance and improved cutting by a turbine blade. [ABSTRACT FROM AUTHOR]

The high solar reflectance and good colour performance are requisite for the practical application of the colour-cool pigment. In this work, Ce-doped Yb 3 Al 5 O 12 and (Y, Yb) 3 Al 5 O 12 ceramic pigments were prepared by the sol-gel method. Both Ce3+ and Ce4+ ions coexist in the doped pigments. Due to the 4f→5d electron transition of Ce3+, the Ce-doped pigments have a selective absorption at around 400–520 nm, which is responsible for the yellow hue. The content of the Ce3+ ion determines the colour performance of the pigment. The size effect from the smaller Yb3+ ion results in an increased content of Ce3+ in the Ce-doped pigments, leading to an improved colour performance. The incorporation of Y3+ ion can effectively decrease the absorption at 975 nm, thereby enhancing the solar reflectance to 80.6 %, while maintaining good colour performance (Yb 0.7 Y 2.1 Ce 0.2 Al 5 O 12 , L* = 91.40, a* = -4.89, b* = 45.33). In a simulation experiment, the ceramic glaze coating based on the prepared pigment showed a temperature reduction of 5.2 °C compared to the commercial yellow pigment ceramic coating. [ABSTRACT FROM AUTHOR]

As the flight speed of aircraft continues to increase, high-temperature wave-transparent materials for radomes or antenna windows face great challenges. The shortage of new high-performance wave-transparent materials is limiting the improvement of aircraft performance. In this work, dielectric and mechanical properties of RE 2 SiO 5 (RE = Ho, Er, Tm, Yb, and Lu) were investigated to explore their application as high-temperature wave-transparent materials. RE 2 SiO 5 (RE = Ho, Er, Tm, Yb, and Lu) ceramics possess relatively low dielectric constant and it is insensitive to the RE species. For the dielectric loss, they gradually decrease as the radius of rare earth ions decreases. In addition, RE 2 SiO 5 (RE = Ho, Er, Tm, Yb, and Lu) possesses good mechanical properties with high hardness and relatively low reduced modulus, and hardness is insensitive to the rare earth ion radii while the reduced modulus increases with the RE3+ ions radius decreases. They are larger than those of fused silica, the most used traditional high-temperature wave-transparent material. The results provide important material selection and optimization guidelines for RE 2 SiO 5 as the candidate for next-generation high-temperature wave-transparent materials. [ABSTRACT FROM AUTHOR]

The influence of the heterogeneous interface is critical for the catalytic activity of the oxygen reduction reaction (ORR). This study demonstrates an enhancement of the electrocatalytic activity of the SrFe 0.9 Nb 0.1 O 3-δ (SFN113) electrode through the construction of a SrFe 0.9 Nb 0.1 O 3-δ -Sr 3 Fe 1.8 Nb 0.2 O 7-δ (SFN113-SFN327) heterogeneous interface. By coating varying amounts of Sr(NO 3) 2 (0.1 g, 0.2 g and 0.3 g) on SFN113 (1 g), SFN113/327 composite electrodes with different amounts of triple conducting oxide SFN327 are in-situ synthesized by high temperature calcination. Electrical Conductivity Relaxation (ECR) tests show that SFN327 has superior oxygen surface exchange performance compared to SFN113, especially at lower temperatures. At 550 °C, the oxygen surface exchange parameter of SFN327 is 4.23 times higher than that of SFN113. Symmetric cell tests with SFN113/327||BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ (BCZYYb)||SFN113/327 configuration and single cell tests with Ni-BCZYYb||BCZYYb||SFN113/327 configuration indicate that the SFN113/327 composite electrode with a mass ratio of 1:0.2 displays the best electrocatalytic performance, achieving a power output of 502 mW cm−2 at 700 °C. The work not only in-situ synthesizes the SFN113/327 triple conducting composite electrode, but also introduces a novel method for developing proton conducting electrode materials. [ABSTRACT FROM AUTHOR]

To ensure the safety of medical personnel in healthcare organizations, radiation-shielding materials like protective clothing are used to protect against low-dose radiation, such as scattered rays. The extremities, particularly the hands, are the most exposed to radiation. New materials that can be directly coated onto the skin would be more cost-effective, efficient, and convenient than gloves. We developed protective creams using eco-friendly shielding materials, including barium sulfate, bismuth oxide, and ytterbium oxide, to avoid harmful effects of heavy metals like lead, and tested their skin-protective effects. Particularly, the radiation-shielding effect of ytterbium oxide was compared with that of the other materials. As shielding material dispersion and layer thickness greatly affect the efficacy of radiation-shielding creams, we assessed dispersion in terms of the weight percentage (wt%). The effective radiation energy was reduced by 20% with a 1.0-mm increase in cream thickness. Ytterbium oxide had a higher radiation-shielding rate than the other two materials. A 28% difference in protective effect was observed with varying wt%, and the 45 wt% cream at 63.4 keV radiation achieved a 61.3% reduction rate. Higher content led to a more stable incident energy-reducing effect. In conclusion, ytterbium oxide shows potential as a radiation-shielding material for creams. [ABSTRACT FROM AUTHOR]

A transparent Er3+,Yb3+:GdMgB5O10 single crystal with dimensions up to 24 × 15 × 12 mm was grown successfully by the high-temperature solution growth on dipped seeds technique from K2Mo3O10-based solvent. The grown crystal was characterized using PXRD, DSC and ATR techniques. Differential scanning calorimetry measurements and SEM analysis of the heat-treated solids revealed Er,Yb:GdMgB5O10 to be an incongruent melting compound with an onset point of 1087 °C. The absorption edge of the Er,Yb:GMBO sample is located in the region of 245 nm, which approximates a value of 4.8 eV. Absorption and emission spectra, and luminescence kinetics, were studied. The energy transfer efficiency from ytterbium to erbium ions was determined. The laser operation in continuous-wave mode was realized and output characteristics were measured. The maximal output power of 0.15 W with a slope efficiency of 11% was obtained at 1568 nm. [ABSTRACT FROM AUTHOR]

A series of MnFe2–xYbxO4 powder nanoparticles (for x = 0, 0.025, 0.075, 0.1, and 0.2) of different crystallite sizes were synthesised using the co-precipitation method. The effect of Yb3+ dopant on the properties of manganese ferrite was characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman measurements, and photoluminescence spectroscopy (PL). The crystallite size and density of the samples have a cubic structure with an Fd3m space group. Their sizes and densities were found to be in the range of 24.8–34.7 nm and 5.07–5.49 g/cm3. FT-IR analysis indicates the presence of two absorption bands in the range 400–600 cm–1, which is a fingerprint region of ferrites. The v2 band (Fe–O stretching mode of the octahedral site) shifts towards the lower wavenumber, which confirms the occupancy of larger-size Yb3+ ions at the octahedral site. The Raman peaks were noted at 228, 295, 405, 502, and 634 cm–1 for undoped manganese ferrite. Based on Raman observations, it has been observed that Mn2+ ions exhibit a preference for occupying octahedral (B) sites by substituting Fe3+ ions. Additionally, rare earth ions have been preferentially observed to occupy octahedral sites. The primary cause for the displacement of Raman bands was ascribed predominantly to the greater radii of rare earth ions in comparison with Fe3+ and Mn2+ ions, and the shifting of the peaks indicates the presence of Yb3+ at the octahedral site. The PL spectrum shows emission at 560 nm with a rise in intensity with an increase in dopant Yb3+, which could be because of the incorporation of Yb3+ in the spinel structure, leading to radiative recombination in the yellow region of the electromagnetic spectrum. [ABSTRACT FROM AUTHOR]

Using a solid-state technique under low temperature conditions, Er3+/Yb3+ co-doped Bi2Mo2O9 phosphors with different concentrations were prepared, exhibiting excellent green up-conversion luminescence property. A thorough investigation was conducted on the phase structure, optical transition, up-conversion luminescence, and down-shifting luminescence properties of the prepared samples. Bi2Mo2O9: Er3+/Yb3+ phosphors excited at 381, 980, and 1550 nm showed strong green fluorescence together with very faint red emission. The mechanism of up-conversion luminescence and its capacity for temperature sensing were examined under the excitation of various wavelengths. Under 980 nm excitation, the maximal relative and absolute sensitivities were determined to be 1.107%K− 1 and 0.756%K− 1 at 303 K and 513 K, respectively. Furthermore, the Judd-Ofelt intensity parameters of Er3+ in Bi2Mo2O9: Er3+/Yb3+ phosphors were calculated using the diffuse reflectance spectra and fluorescence lifetime of Er3+. In addition, material was combined with polyacrylic acid to make an anti-counterfeiting pattern. The results indicate that Bi2Mo2O9: Er3+/Yb3+ phosphor is an excellent green phosphor with optical temperature measurement function, and it also has certain applications in the field of anti-counterfeiting. [ABSTRACT FROM AUTHOR]

This work presents the results of studying dilute aqueous solutions of commercial Ln(NO3)3 · xH2O salts with Ln = Ce-Lu using X-ray diffraction (XRD), IR spectroscopy, X-ray absorption spectroscopy (XAS: EXAFS/XANES), and pH measurements. As a reference point, XRD and XAS measurements for characterized Ln(NO3)3 · xH2O microcrystalline powder samples were performed. The local structure of Ln-nitrate complexes in 20 mM Ln(NO3)3 · xH2O aqueous solution was studied under total external reflection conditions and EXAFS geometry was applied to obtain high-quality EXAFS data for solutions with low concentrations of Ln3+ ions. Results obtained by EXAFS spectroscopy showed significant contraction of the first coordination sphere during the dissolution process for metal ions located in the middle of the lanthanide series. It was established that in Ln(NO3)3 · xH2O solutions with Ln = Ce, Sm, Gd, Yb (c = 134, 100, 50 and 20 mM) there are coordinated and, to a greater extent, non-coordinated nitrate groups with bidentate and predominantly monodentate bonds with Ln ions, the number of which increases upon transition from cerium to ytterbium. For the first time, the antibacterial and antifungal activity of Ln(NO3)3 · xH2O Ln = Ce, Sm, Gd, Tb, Yb solutions with different concentrations and pH was presented. Cross-relationships between the concentration of solutions and antimicrobial activity with the type of Ln = Ce, Sm, Gd, Tb, Yb were established, as well as the absence of biocidal properties of solutions with a concentration of 20 mM, except for Ln = Yb. The important role of experimental conditions in obtaining and interpreting the results was noted. [ABSTRACT FROM AUTHOR]