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Photon upconversion luminescence at the molecule scale is a rarely observed phenomenon despite possessing colossal potential for basic research and reality applications. Here we show that the eight-coordinate erbium molecular complex composed of Er

Significant work has been done to develop nanoparticle contrast agents for computed tomography (CT), with a focus on identifying safer and more effective formulations. Contrast agents for spectral photon-counting computed tomography (SPCCT), a fast-growing imaging modality derived from conventional CT, have also recently gained considerable attention. In this study, we explored the synthesis of ultrasmall ytterbium nanoparticles (YbNP) and demonstrated that, potentially, they can be used as conventional CT and SPCCT contrast agents. These nanoparticles were tested

Optical coherence tomography (OCT) is a novel imaging modality that provides volumetric in-vivo high-resolution (1-15μm) images in real-time. Multi-channel OCT (MOCT) imaging utilizes many imaging channels simultaneously yielding several advantages over single-channel OCT. The benefits of MOCT are at the cost of the added requirement of several imaging beams, which demands high power output from the laser source. Dual-core Ytterbium (Yb) doped fiber was used in two configurations to demonstrate its use as a MOCT light source gain medium: 1) within a ring cavity resonator and 2) in a post-amplification regime with a low powered seed-laser. The amplification wavelength range was tailored to be centered at ~1060nm, where light absorption and scattering is at a minimum in water. In the post-amplification configuration, the output power was increased from 5mW to >200mW, with the axial resolution reducing from 10μm to 12μm. We also present initial in-vivo MOCT imaging of a tadpole.

In this study, we measure the absolute isotope ratios of ytterbium (Yb) by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) using an optimized regression model for mass bias correction. A rhenium (Re) reference material (NIST SRM 3143), which has been characterized previously, is selected as a primary calibrator to calibrate the absolute Yb isotope ratios for three Yb materials (GSB, Alfa Yb, and GBW). The three-isotope plot for all collected data indicates that the results of Yb isotope ratios obtained are not affected by any polyatomic interferences and the mass-independent isotopic fractionation. Furthermore, the recalibrated Hf historical isotope ratios by using the absolute Yb isotopic composition obtained in this study for the isobaric interference correction on Hf isotopes are in agreement with the original historical values. This work has further demonstrated the applicability of the regression model for the calibrated measurements of absolute isotope ratios using MC-ICP-MS. The three mono-elemental Yb standard solutions are thus proposed as the reference materials for Yb isotope ratio measurements in environmental and geoscience applications.

Circularly polarized luminescence (CPL) in two subregions of the near-infrared (NIR) has been achieved. By leveraging the rigidity and diminishing detrimental vibrations of the heterobimetallic binolate complexes of erbium [(Binol)

Materials with high thermo mechanical properties are required as laser media for high-powered lasers. One of such materials is lutetium-aluminum garnet (LuAG) doped with ytterbium. In the present work, we discuss for the first time a full comparative study of 5% Yb-doped LuYAG ceramics with variation Lu/Y ratio. Samples were prepared with addition of B2O3, MgO and SiO2 which were used as sintering aids. Grain sizes, shrinkage curves, lattice constants and transmission spectra were measured for all samples. Thermal conductivity was measured in a wide temperature range for all studied samples. Output power of 12 W and 60% slope efficiency were obtained on the 5% Yb:LuAG disk laser.

In this work, we establish a comprehensive spectral model to realize effective design of high-power ytterbium-Raman fiber amplifiers (YRFAs) employing different types of Raman-pump lasers, and propose an intuitive approach for the optimization of high-power YRFAs. Quantitative comparisons with the experimental results are given in two high-power YRFAs employing Raman-pump lasers with different spectral linewidth. The consistency of measured and simulated power ratios and spectral properties of different components in the two YRFAs confirms the fidelity of the spectral model. Further theoretical analysis reveals that the impact of Raman-pump lasers on YRFAs is mainly determined by the relative intensity noise (RIN) of Raman-pump lasers up to the cutoff frequency of the pump RIN transfer function of the YRFA. Notably, the RIN of Raman-pump lasers could provide a well reference for the superior design of Raman-pump lasers in high-power YRFAs.

International audience; Zinc oxide optical ceramics containing 0 – 2 wt% ytterbium are prepared byuniaxial hot pressing of commercial oxides at 1150 and 1180 °C. The ceramics have themain crystalline phase of hexagonal wurtzite-type ZnO. Ytterbium ions do not enter theZnO crystals but form a cubic sesquioxide phase of Yb2O3 located at the ZnO grainboundaries. Yb acts as an inhibitor for the ZnO grain growth. The ceramics exhibittransmittance up to 60% in the visible. Their transmission in the infrared is determinedby the free charge carrier absorption. The Yb3+ ions are found in C2 and C3i sites in Yb2O3crystals. Under X-ray excitation, the ceramics exhibit intense luminescence bands in theblue (near-band-edge emission) and green (defect emission) whose positions, intensitiesand decay times depend on the Yb content. Yb2O3 causes a redistribution of luminescenceintensity in favor of the near-band-edge emission and fastens the emission decay.

We report enzyme-powered upconversion-nanoparticle-functionalized Janus micromotors, which are prepared by immobilizing uricase asymmetrically onto the surface of silicon particles, to actively and rapidly detect uric acid. The asymmetric distribution of uricase on silicon particles allows the Janus micromotors to display efficient motion in urine under the propulsion of biocatalytic decomposition of uric acid and simultaneously detect uric acid based on the luminescence quenching effect of the UCNPs modified on the other side of SiO

In this study, we employed a luminescenct agent CsPbCl3 perovskite nanocrystal for Cu2+ detection, and achieved a prominent enhancement in sensitivity by the introduction of ytterbium acetate (Yb(OAc)3). The introduced Yb(OAc)3 is capable of causing a morphology transformation of CsPbCl3 nanocrystals from initial nanocubes into one-dimensional (1D) nanowires (NWs). The formed 1D CsPbCl3 NWs paved a direct charge transport path and exhibited low defect density as well as superior conductivity, which were beneficial to accelerating the rapid electron transport from the luminescent agent to Cu2+, and to give rise to an efficient inhibition of undesired charge trap, respectively. Besides, AcO− rendered a reduced steric hindrance during the formation of a copper-based counter-ion pair, thus improving the adsorption capacity of Cu2+ on the surface of the luminescent agent, CsPbCl3 nanocrystals. As results, the 1D Yb(OAc)3 passivated CsPbCl3 NWs exhibited efficient luminescence quenching for enhanced detection sensitivity. This Yb(OAc)3-involved system exhibited a detection limit as low as 0.06 nM in the Cu2+ detection window range from 0 to 1000 nM, and such value is optimal in the documented works for Cu2+ detection based on luminescent perovskite materials.

An effort, investigate the photophysical belongings on pyrin-3-amine with 1-acetyl-2, 4-dihydroxybenzene Schiff base Erbium, and Ytterbium multiplexes have been created then categorised in spectroscopic methods identical UV, FTIR, Fluorescence, then Nuclear magnetic resonance spectroscopy. Proved thermal characterization of Schiff base metal complexes was to have high thermal stability by the TGA-DTA technique. Erbium and Ytterbium complexes have high luminescence in nature compared to a free ligand. A bioimaging study with Schiff base metal complexes is fluorescent staining dyes. It is appreciated quality in low cytotoxicity, simple preparation, photostability, and smudged cytoplasm structure. The quantum yield of lanthanides contributes to the brightness of Schiff base rare earth elements. The aim on molecular constructions limits intermolecular metal-ligand connections.

Integrating chemodynamic therapy (CDT) and photodynamic therapy (PDT) into one nanoplatform can produce much more reactive oxygen species (ROS) for tumor therapy. Nevertheless, it is still a great challenge to selectively generate sufficient ROS in tumor regions. Meanwhile, CDT and PDT are restricted by insufficient H

Formation of Yb and Tm radioisotopes upon irradiation of ytterbium of natural isotopic composition by bremsstrahlung photons with energies up to 55 MeV was studied. The yield of the medical radionuclide 167Tm was (7.8 ± 1.1) × 103 Bq × μA-1 × h−1 × cm2 × g−1. Thulium radioisotopes were separated from irradiated ytterbium target by extraction chromatography on the LN Resin sorbent in nitric media. Efficient separation of tracer amounts of thulium from tens of milligrams of ytterbium could be achieved. The method can be of practical importance for the production of 167Tm when using a 168Yb enriched target.

Monolithic SiC, for the first time, was seamless joined at a low temperature of 1200 °C using electric field-assisted sintering technology. A 300 nm Yb coating on SiC was used as the joining filler to form Yb3Si2C2 via an in-situ reaction with the SiC. A liquid phase was formed by an eutectic reaction between Yb3Si2C2 and SiC. Almost completely seamless joints were formed by the precipitated SiC grains, which were fully consolidated with the SiC matrix with the help of in-situ formed liquid phase, followed by its elimination under the uniaxial pressure. The bending strength of the seamless joint joined at 1500 °C for 15 min was as high as 257.2 ± 31.1 MPa, which was comparable to the strength of the SiC matrix. As a result, the failure occurred in the matrix indicated a sound joint was obtained. The proposed low temperature seamless joining could potentially be used for joining of SiC-based composite.

Phosphate glass with composition of (P2O5)47–(Na2O)23–(Al2O3)6–PbO(24−x)–(Yb2O3)x where x = 0.1, 1 and 3 of Yb2O3 in mole % has been prepared via traditional melt-quenching method. The ultraviolet and NIR absorption spectra have been studied in the range 190–1000 nm. Also, photoluminescence spectra for glass samples exposed to excited wavelength at 915 nm or emitted wave length at 1008 nm has been investigated. The ultraviolet (UV and NIR) absorption changes due to the addition of Yb ions have been interrelated to the local structure of Yb3+ ions. The photoluminescence evolution and the role of UV absorption bands in the photodarkening process have been discussed. The results indicated that the strong UV absorption bands in the range at about 237 nm were primarily attributed to the spontaneous charge-transfer probability for Yb3+: 2F5/2 → 2F7/2. The charge-transfer (CT) transition from O2– to Yb3+ and the position of CT bands shifted to a higher energy level. The ESR results indicate distinct paramagnetic centers for glass containing 3% Yb3+ when irradiated with 10 kGy. The results showed that some of the formed ODC can be healed by irradiation and the Al/Na/Pb/P glass network act as a good environment for Yb2O3 distribution that can decrease photodarkening effect.

A ytterbium triflate-catalyzed diastereoselective [3 + 2] cycloaddition of quinoxalinones with donor-acceptor cyclopropanes and cyclobutanes is described. A series of tetrahydropyrrolo-quinoxalinone derivatives were obtained in high yields (up to 96%) with excellent diastereoselectivities (up to 46:1). Other medicinally important heterocycles like benzoxazinone, isoquinoxalinone, and dibenzoxazepine derivatives were also suitable for the desired annulation reaction. The current method is applicable for the scale-up reaction. Further, the utility of this annulation reaction is demonstrated by the synthesis of densely functionalized proline derivatives.

In this article, homogeneous multi-functional materials and artificially design method are proposed to design ultra-thin metasurfaces, which broaden the application over a wide range of temperatures due to their excellent mechanically-thermally stable structure and electromagnetic functional performance. Ideal environmental barrier coating material of ytterbium monosilicate (Yb2SiO5) possesses stable dielectric property over a wide temperature and frequency range. As a thermal corrosion resistant coating, NiCrAlY possesses excellent conductivity at high temperatures. These two materials are selected as substrate and conductive units to composite temperature insensitive ultra-thin refractory metasurface coating (RMC) for wideband radar cross section (RCS) reduction. Three types of RMC patterns are discussed, namely chessboard, staggered, and random. The prototype of staggered pattern was prepared using atmospheric plasma spraying (APS) technique. Both the simulated and experimental results indicated that RCS is reduced remarkably in a wideband frequency, as well as demonstrated stable reduction performance over a broad range of temperatures. Along with a protective layer of Yb2SiO5, only a thickness of 1.4 mm is required. The protective layer is employed to isolate the contact between the structural layer and the outside environment, which can significantly increase the service life of the metasurface. This work brings bright prospects for various kind of metasurfaces in practical high temperature applications and significantly enriches the research of metasurfaces.

Ultra-narrow clock transition of ytterbium atoms has enabled not only quantum metrology but also quantum simulation of various quantum phenomena. One of such examples is a new possibility of realizing dissipative open quantum systems with minimal heating by optical pumping through the clock transition. Nevertheless, the access to the clock transition and relevant optical pumping often requires a complex laser system. Here we delineate a simple design and characterization of a home-made clock laser system that is capable of driving ytterbium clock transition at 578 nm. A fundamental laser at 1156 nm based on a quantum dot gain chip in a long external cavity configuration seeds the standard bow-tie cavity and generates up to 45 mW power of frequency-doubled yellow light at 578 nm. We have stabilized the laser frequency to a high-finesse ULE (ultra-low expansion) cavity via electronic feedback to the current. We examine the atomic spectroscopy at the clock transition in fermionic $$^{173}$$ Yb atoms, which would allow us to implement controlled dissipation with minimal heating. With the clock laser system built in this work, we envision exploring non-Hermitian physics in various platforms including spin-orbit-coupled fermions and topological bands.

Extremely short, high-energy pulses are essential in modern ultrafast science. In a seminal paper in 19961, Nisoli and co-workers demonstrated the first intense pulse compression employing a gas-filled hollow-core fibre. Despite the huge body of scientific work on this technology stemming from ultrafast and attosecond research, here we identify an unexplored few-cycle visible-light generation mechanism, which relies on the nonlinear mixing of hollow-core fibre modes. Using a commercially available ytterbium laser, we generate 4.6 fs, 20 μJ pulses centred at around 600 nm (~2 cycles, ~4 GW peak power), ~40 times shorter than the input 175 fs, 1 mJ pulses at 1,035 nm. Our approach thus directly projects few-hundred-femtosecond-long infrared pulses into the single-cycle regime at visible frequencies, without the need for additional post-compression. As a powerful application of our findings, we present a compact, multicolour pump–probe set-up with a temporal resolution of a few optical cycles. Direct generation of few-cycle high-energy visible pulses is demonstrated via the nonlinear mixing of hollow-core fibre modes. Compression of near-infrared laser pulses by a factor of 40 with no additional dispersion compensation delivers 4.6 fs, 20 μJ pulses (~2 cycles, ~4 GW peak power) centred at around 600 nm.

Based on a distributed-feedback (DFB) semiconductor laser, an ytterbium fibre amplifier, an Nd : YVO4 amplifier, and a frequency converter, we designed a hybrid picosecond laser for satellite laser ranging. A gain exceeding 108 is achieved while maintaining the temporal shape and spectrum of the pulses, with a low noise level and a divergence close to the diffraction limit. The pulse energy after conversion to the second harmonic at λ = 532 nm is 2.2 mJ with a duration of 27 ps and a repetition rate of 1 kHz. It is shown that the main effects limiting the peak power are spectrum broadening due to self-phase modulation in a fibre amplifier and large-scale self-focusing in the Nd : YVO4 amplifier. Optimisation of the amplifier geometry and the use of a uniform profile of the pump radiation intensity make it possible to reduce the effect of self-focusing and increase the energy efficiency of the amplifier.

Experimental data have been obtained for the relaxation rates of population, orientation, and alignment of the 174Yb(6s6p)3P1 level due to collisions of 174Yb atoms with atoms of noble gases.

International audience; The combination of physical properties sensitive to molecular chirality in a single system allows the observation of fascinating phenomena such as Magneto-Chiral Dichroism (MChD) and Circularly Polarized Luminescence (CPL) having potential applications for optical data readout and display technology. Homochiral monodimensional coordination polymers of YbIII were designed from a 2,15-bis-ethynyl-hexahelicenic scaffold decorated with two terminal 4-pyridyl units. Thanks to the coordination of the chiral organic chromophore to Yb(hfac)3 units, efficient NIR-CPL activity is observed. Moreover, the specific crystal field around the YbIII induces a strong magnetic anisotropy which leads to a slow magnetic relaxation (SMM) and a remarkable room temperature MChD. The MChD-structural correlation is supported by computational investigations.

Lanthanide-doped fluoride nanocrystals (NCs) are known to exhibit unique optical properties, such as upconversion and downconversion luminescence (UCL and DCL), which can be employed for various applications. In this work, we demonstrate that by doping praseodymium(III) and ytterbium(III) ions (Pr

We present a numerical analysis of the thermal effect of an Yb3+-doped fiber segment subjected to different temperature variation profiles, with the intention of determining the best energy conversion efficiency. The analysis is carried-out using different pump schemes and singular temperature profiles in Yb3+-doped fibers. The study indicates that a temperature distribution, with a concave parabolic profile along the fiber axis, shows higher stability in a fiber amplifier scheme, and it therefore becomes steadier at higher pump power level. Additionally, we find that for a constant temperature profile of 20 °C, the highest energy conversion efficiency occurs with a fiber segment of approximately 1.8 m, while for a constant temperature of 200 °C the maximum conversion occurs for a fiber span approximately 2.31 m. This makes it useful for using it as a sensor, at a temperature in a range of 20 °C to 200 °C. These results can be employed as a tool for optimization in the design of fiber lasers and amplifiers as sensors.

International audience; Drug-loaded liposomes are typical examples of nanomedicine. We show here that doxorubicin, the anti-cancer agent in the liposomal drug Doxil ® , can sensitize Ytterbium (Yb 3+ ) and generate its near infrared (NIR) emission. When doxorubicin and amphiphilic Yb 3+ chelates are incorporated into liposomes, the sensitized emission of Yb 3+ is dependent on the integrity of the particles which can be used to monitor drug release. We also established the first demonstration that the NIR Yb 3+ emission signal is observable in living mice following intratumoral injection of the Yb 3+ -doxorubicin-liposomes, using a commercial macroscopic setup equipped with a near-infrared camera.

In order to prevent counterfeiting of down fiber from consumers, rare earth fluorescent materials are developed in the field of material identification and anticounterfeiting. Herein, the development of verifiable down fiber based on infrared excitation-infrared emission was described. A novel method was approached to prepare security down fiber, which involved modification of down-conversion nanoparticles (DCNPs) by sulfonic groups and self-assembly onto down fiber through electrostatic force. DCNPs were successfully prepared from ytterbium-deposited NaYF4 nanoparticles using a complexation precipitation approach, in which the trivalent ytterbium ions served as the luminescent center. Sulfonic down-conversion nanoparticles (SO3-SiO2@DCNPs) were fabricated by the hydrolysis of 3-mercaptopropyl triethoxysilane (MPTES) and next oxidation to enhance the combination of the DCNPs with down fiber. The synthesis of DCNPs and SO3-SiO2@DCNPs and its pendant to down were confirmed by XRD, SEM, XPS, FT-IR, Zeta potential meter, and PL, which revealed the presence of DCNPs in the size average 86 nm. The obtained DCNPs and security down fiber were launching an invisible red-shifted emission of 930∼1080 nm (corresponding to the 2F5/2 ⟶ 2F7/2 transitions in Yb3+). After washing, the infrared emission of security down fiber was evaluated and proved to be effective with fine results, which showed its potential application in the field of security.

Upconversion nanocrystals have been extensively investigated for optical imaging and biomedical applications1,2. However, their photoluminescence is strongly attenuated by surface quenching as the nanocrystal size diminishes3. Despite considerable efforts4,5, the quenching mechanism remains poorly understood. Here we report that surface coordination of bidentate picolinic acid molecules to NaGdF4:Yb/Tm nanoparticles enhances four-photon upconversion by 11,000-fold. Mechanistic studies indicate that surface ligand coordination reconstructs orbital hybridization and crystal-field splitting, minimizing the energy difference between the 4f orbitals of surface and inner lanthanide sensitizers. The 4f-orbital energy resonance facilitates energy migration within the ytterbium sublattice, impeding energy diffusion to surface defects and ultimately enhancing energy transfer to the emitters. Moreover, ligand coordination can exert energy-level reconstruction with a ligand–sensitizer separation of over 2 nm. These findings offer insights into the development of highly emissive nanohybrids and provide a platform for constructing optical interrogation systems at single-particle levels. Strong lanthanide-doped upconversion luminescence enhancement is achieved by the use of surface molecules which enhance four-photon upconversion emission. The results may lead to new, highly emissive, nanohybrid systems.

Chemotherapy can induce toxicity in the central and peripheral nervous systems and result in chronic adverse reactions that impede continuous treatment and reduce patient quality of life. There is a current lack of research to predict, identify, and offset drug-induced neurotoxicity. Rapid and accurate assessment of potential neuropathy is crucial for cost-effective diagnosis and treatment. Here we report dynamic near-infrared upconversion imaging that allows intraneuronal transport to be traced in real time with millisecond resolution, but without photobleaching or blinking. Drug-induced neurotoxicity can be screened prior to phenotyping, on the basis of subtle abnormalities of kinetic characteristics in intraneuronal transport. Moreover, we demonstrate that combining the upconverting nanoplatform with machine learning offers a powerful tool for mapping chemotherapy-induced peripheral neuropathy and assessing drug-induced neurotoxicity.

Nanopowders of the compositions BaHf1 – xYbxO3 – δ (x = 0.04, 0.08, 0.10) and BaCe0.9 – xZrxY0.1O3 – δ (x = 0, 0.5, 0.6, 0.7, 0.8) were synthesized by the combined crystallization of nitric acid salts and the citrate-nitrate method. Those nanopowders were used to produce ceramic materials with a cubic crystal structure of the perovskite type, with a grain size of ~20–70 nm. The study of electrophysical properties revealed that they have a proton type of conductivity in the temperature range of 500–700°C; σ = 10–2–10–5 S/cm. The type and mechanism of electrical conductivity of ceramics of the composition BaHf1 – xYbxO3 – δ (x = 0.04, 0.08, 0.10) were studied both experimentally and using theoretical calculations by computer modeling using the electron density functional method; the results are in good agreement. The research shows the prospects of using the obtained ceramic materials as proton-conducting electrolytes for solid oxide fuel cells.

A distributed temperature monitoring inside a cavity of ytterbium DFB and holmium fiber lasers has been demonstrated with a spatial resolution of 1 and 5 mm, respectively, for the first time to the best of our knowledge. For this, we use an optical backscatter reflectometer, which measures intracore temperature, and compare it with the data of an IR thermographic camera, which measures temperature from the surface of a fiber. In the case of holmium fiber laser pumped at a wavelength of 1125 nm with a power of 6 W, the maximum temperature variation along the ∼3-m active fiber reaches ∼60 °C. In the case of ytterbium DFB laser, we observe a strong inhomogeneity of the temperature along the DFB cavity, which leads to a significant decrease in the lasing efficiency. When pumped by a single-mode laser diode at a wavelength of 976 nm with a power of up to 526 mW, the maximum temperature difference reaches 37 °C for the 37-mm DBF cavity.

Organo-inorganic hybrid materials based on inorganic oxyfluoride lead-borosilicate glass matrices and the metal-complex compound tris-(8-oxycholate) ytterbium (III) were obtained by the melt method. The spectral-luminescence properties of tris-(8-oxycholate) ytterbium and hybrid materials in the visible and IR ranges were studied under different excitations (377 and 785 nm). It is shown that the intensity of IR luminescence in the initial metal-complex luminophore surpasses the luminescence in the visible range and vice versa in the obtained hybrid materials — the intensity of visible luminescence significantly surpasses the IR-luminescence.

The comparison of optical oscillators is used both to determine their spectral characteristics and to perform fundamental research. To describe each individual laser system, it is necessary to compare at least three independent laser oscillators. Three ultrastable lasers with wavelengths of 1140, 1550, and 871 nm located in different laboratories at the Lebedev Physical Institute have been compared. A femtosecond frequency comb has been used to transfer stability between different spectral ranges. A fractional frequency instability has been obtained with the three-cornered hat method and phase noise of each laser has been analyzed. Using this method, it has been shown that the characteristics of the laser system at a wavelength of 871 nm are appropriate to control the quantum state of an optical qubit on a quadrupole transition in an ytterbium ion with a n-atural width of 3.1 Hz.

Ceramic composite materials with a density not lower than 98.5% of the theoretical value were produced from powders containing 20 and 50 mol % corundum and tetragonal zirconia stabilized with ytterbia (3 mol %), [3Yb–TZP], modified with 1 mol % CaO, which were synthesized by hydrolysis sol–gel method. The use of ytterbium cation to stabilize tetragonal zirconia leads to the formation of two ZrO2 phases with different tetragonal symmetry. The introduction of CaO causes an increase in the content of the ZrO2 solid solution phase similar in composition to the cubic phase, which leads to lower strengths of doped composites in comparison with the initial ones.

International audience; A dimeric beta-diketiminato ytterbium(II) hydride affects both the two-electron aromatization of 1,3,5,7-cyclooctatetraene (COT) and the more challenging two-electron reduction of polyaromatic hydrocarbons, including naphthalene (E-0=-2.60 V). Confirmed by Density Functional Theory calculations, these reactions proceed via consecutive polarized Yb-H/C=C insertion and deprotonation steps to provide the respective ytterbium (II) inverse sandwich complexes and hydrogen gas. These observations highlight the ability of a simple ytterbium(II) hydride to act as a powerful two-electron reductant at room temperature without the necessity of an external electron to initiate the reaction and avoiding radicaloid intermediates.

Dense environmental barrier coatings (EBCs) are an essential prerequisite to exploit the advantages offered by SiC-based fiber reinforced ceramic matrix composites (CMCs) to increase efficiency in gas turbines. Today's state-of-the art materials for application as EBCs are rare-earth (RE) silicates which, however, form amorphous phases upon rapid quenching from the melt. This makes their processing by thermal spray a challenge. Recently, high velocity oxygen fuel (HVOF) spraying was proposed as potential solution since the melting degree of the feedstock can be controlled effectively. This work studies the deposition of ytterbium disilicate (YbDS) at short stand-off distances and variant total feed rates and oxy-fuel ratios of the working gas. It was found that the overall degree of crystallinity could be kept at high level above 90%. The kinetic energy transferred by impinging particles was found to be an effective parameter to control the densification of the coatings. Porosities well below 10% were achieved while fully dense coatings were impeded due to the progressive accumulation of stresses in the coatings.

Exploring highly efficient near-infrared (NIR) emitting materials is desirable for the advancement of next-generation smart NIR light sources. Different from most reported Cr3+-doped emitters with far-red emissions, Yb3+-activated phosphors are expected to yield pure NIR (∼1000 nm) light. Herein, a new hot-injection route using all metal-oleate salts to fabricate Yb3+-doped CsPbCl3 perovskite nanocrystals (PeNCs) is reported for the first time, which produce PeNC-sensitized Yb3+ NIR emission with photoluminescence quantum yields (PLQYs) higher than 100%. With the help of temperature-dependent PL spectra, femtosecond transient absorption spectra, and time-resolved PL spectra, it is evidenced that the in situ produced intrinsic shallow trap states in a CsPbCl3 host play a key role in facilitating the picosecond nonradiative cooperative energy transfer from PeNCs to two Yb3+ dopants simultaneously. Using the optimized Yb3+:CsPbCl3 quantum cutters, a phosphor-converted NIR light-emitting diode (pc-NIR-LED) is fabricated, exhibiting an external quantum efficiency of 2%@28 mA, a high NIR output irradiance of 112 mW/cm2@400 mA, and excellent long-term stability. Finally, the designed pc-NIR-LED is demonstrated to have great potential as an invisible night-vision light source.

The article presents the results of studies of the surfaces of parts processed by the contactless method of laser polishing. The results of technological surface treatment using a laser technological complex based on an ytterbium fibre laser with a power of 5 kW are presented. The results of studies of the surface roughness of the samples after laser treatment, including the non-uniform character due to the redistribution of the liquid metal melt over the surface, are shown. Requirements for metrological support of additive technology have been developed using the example of the process of laser remelting in order to improve quality and further automation.

Thin natEr2O3 targets were irradiated on cyclotron by 60 MeV alpha particles. Thulium and ytterbium radioisotopes, formed during irradiation, were separated from the target material and the one from another by extraction chromatography using Ln Resin in nitric solution. 165Er, formed mainly by the decay chain 165Yb → 165Tm → 165Er, was isolated after ingrowth in the thulium fraction by an additional extraction chromatography step using the same sorbent. Recovery of thulium and ytterbium radioisotopes was > 90%.

Ytterbium disilicate (Yb2Si2O7) and lanthanum zirconate (La2Zr2O7) powders were synthesized by solvent gel (sol-gel) method. To improve the oxidation resistance of Cf/SiC composites at high-temperature and high-speed gas scour environment, a tri-layer La2Zr2O7/Yb2Si2O7/SiC EBCs was prepared on the surface of Cf/SiC composites by chemical vapor deposition (CVD) and sol-gel method combined with air spraying. Results show that tri-layer La2Zr2O7/Yb2Si2O7/SiC coating showed better oxidation resistance for Cf/SiC samples than bi-layer Yb2Si2O7/SiC coating, which can efficiently prevent the oxidation of Cf/SiC samples in gas scour environment at 1773 K for 24 thermal cycles (360 min) with a weight loss of 7.06 × 10−3 g cm-2. Microstructure characterization revealed that crack deflection phenomenon in tri-layer coating can largely avoid the formation of penetrating cracks and even improve the oxidation resistance of the coating. After the corrosion of tri-layer coating in high-speed and high-temperature gas, a small amount of coating fell off and eventually formed coating corrosion pit area and coating fracture area.

The facile synthesis of ytterbium tetrahydroaluminate Yb(AlH4)3 is conducted by a mechanochemical procedure under hydrogen atmosphere for the first time. Results show that the synthesized Yb(AlH4)3 remains as an amorphous state. The thermal decomposition of Yb(AlH4)3 goes through a four-stage pathway with several amorphous intermediate phases during the process. The first dehydrogenation step of Yb(AlH4)3 presents a relatively low apparent activation energy of 99.6 kJ mol−1, and ninety percent of the hydrogen from this stage can be liberated within 20 min at 160 °C. Rehydrogenation tests above 160 °C and 14 MPa hydrogen pressure demonstrate the unsuccessful rehydrogenations of the first decomposition step due to the formation of a thermodynamically more stable compound YbHCl.

Yb:CaWO4 and Yb, Nb:CaWO4 single crystals have been grown by the Czochralski method in air and in protective atmospheres and subjected to additional annealing in air, in CO/CO2 atmosphere, and in forevacuum. The optical absorption spectra in the range from 250 to 1500 nm and the luminescence spectra of these crystals in the visible and near-IR spectral regions upon UV excitation have been investigated. It is shown that additional introduction of Nb5+ ions into Yb:CaWO4 crystal increases by an order of magnitude (almost to unity) the Yb3+ distribution coefficient between CaWO4 crystal and melt. It is found that optical excitation of the crystals in the range of 260–355 nm induces down-conversion luminescence of Yb3+ ions from the 2F5/2 level in the vicinity of 1 µm. An increase in the oxidative potential of synthesis atmosphere, as well as the introduction of niobium into the crystal composition, weakens this luminescence. A consistent pattern explaining the nature of the donor centers involved in down-conversion population of excited state 2F5/2 of Yb3+ in the crystals is proposed. Within this pattern, Yb2+ ions play the role of these donor centers. Another (much less efficient) mechanism of population of the 2F5/2 level is intracenter relaxation from the higher-lying charge transfer excited state within Yb3+ ions. At the same time, it is confirmed that color centers based on oxygen vacancies and partially reduced tungsten ions, as well as self-trapped excitons on tungstate complexes, are not involved in population of the excited state 2F5/2 of Yb3+ ions, and the optical centers formed in Yb:CaWO4 crystals as a result of vacuum annealing suppress ytterbium luminescence.

Lanthanum extraction from chloride-acetate solutions using mixtures of bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) and caprylic acid in hexane has been studied depending on the composition of aqueous and organic phases. Based on the results, it is found that the lanthanum extraction from chloride-acetate solutions proceeds according to a cation-exchange mechanism occurring in the organic phase with the prevailing formation of Cyanex 272 complexes solvated with caprylic acid molecules. It is shown that, when the process is carried out fusing acetic acid–acetate solutions, it is quite possible to separate lanthanum and ytterbium while attaining high separation coefficients.