Rare-earth Ions Er Research Articles

Efficient and tunable broadband mid-infrared luminescence through energy transfer in CsPb1-x(Er/Yb/Ho)xBr3 perovskite fluoride glasses for CO2 monitoring in H2 energy

Inorganic CsPbBr3 perovskites have garnered significant attention for their excellent optoelectronic properties, particularly in the visible region. However, their great potential for mid-infrared applications has rarely been reported. In this study, we successfully synthesized CsPb1-x(Er/Yb/Ho)xBr3-ZBLAN perovskite fluoride glasses, which exhibit efficient and tunable broadband mid-infrared luminescence. We utilized this perovskite material to fabricate a detection device for measuring carbon dioxide impurity concentrations in hydrogen energy systems. By substituting the Pb2+ ions with rare earth ions Er3+/Yb3+/Ho3+, we achieved continuous tunability within the wavelength range of 2.6–3 μm. Absorption and emission cross sections (σabs and σem) of 0. 25CsPb1-x(Er/Yb/Ho)xBr3-ZBLAN are 3.14×10−20 cm2 and 3.45×10−20 cm2. These findings highlight the potential of CsPb1-x(Er/Yb/Ho)xBr3 perovskite fluoride glasses for future applications in broadly tunable mid-infrared light emitting and laser technologies. Overall, our results demonstrate the broad utility of CsPb1-x(Er/Yb/Ho)xBr3 perovskite fluoride glass for tunable mid-infrared luminescence and laser applications.

Mechanical, thermal and CMAS resistance properties of high-entropy (Gd0.2Y0.2Er0.2Tm0.2Yb0.2)2Zr2O7 ceramics

A high entropy zirconate ceramic (Gd0.2Y0.2Er0.2Tm0.2Yb0.2)2Zr2O7 (HEZ) with fluorite structure has been synthesized by solid state reaction and high temperature sintering successfully. The investigation indicated that HEZ has ultra-low thermal conductivity (0.82 W × m−1 × K−1 at 1200 °C), similar thermal expansion coefficient (10.61 × 10−6 K−1 at 1300–1400 °C) with that of YSZ, excellent mechanical properties (hardness, elastic modulus, fracture toughness), and great CMAS corrosion resistance. Emphasis is given to discussing the CMAS wetting, corrosion process and failure mechanisms using high-temperature in-site wetting method and transmission electron microscopy (TEM). The results show that the HEZ exhibits better corrosion resistance than single rare earth zirconate Gd2Zr2O7 due to the coupling effect of anti-wettability, gradient diffusion rate and multicomponent apatite crystallization produced by doping rare earth ion (Gd3+, Y3+) close to Ca2+ radius and rare earth ion (Er3+, Tm3+, Yb3+) with small ion radii. In the comprehensive view, (Gd0.2Y0.2Er0.2Tm0.2Yb0.2)2Zr2O7 is a competitive candidate for high reliability TBC materials.

Designing Er<sup>3+</sup>/Ho<sup>3+</sup>-Doped Near-Infrared (NIR-II) Fluorescent Ceramic Particles for Avoiding Optical Absorption by Water

Rare-earth-doped ceramics, which are near-infrared (NIR) fluorescent materials, have applications as photonic materials in various fields, including medical biology. The NIR wavelength range in which these rare-earth-based materials function is highly transparent in biological tissues and is suitable for deep-tissue imaging. However, the most commonly used 980-nm excitation light is partially absorbed by the water involved in the observation system. In the present study, we focused on the wavelength bands of 800-nm excitation and 1150-nm emission, where no water absorption exists, and investigated the rare-earth doping composition to obtain a ceramic material, NaYF4, with the above excitation and emission wavelengths. NaYF4 particles co-doped with rare-earth ions Er3+ (sensitizer to 800 nm) and Ho3+ (emitter at 1150 nm) were designed for over-1000 nm NIR fluorescent probes. The fluorescence intensity at 1150 nm was maximum at a rare-earth composition of Y3+: Er3+: Ho3+ = 82:14:4 (mol%). The obtained fluorescent Er3+/Ho3+-doped NaYF4 particles exhibited a long fluorescence lifetime (3300 ± 120 μs at 25℃), which is characteristic of rare-earth elements. Er3+/Ho3+-doped NaYF4 is expected to have applications as a long-lifetime NIR-II fluorescent material with the highest transparency in biological tissues.

Synthesis of Barium Tungstate Up-Conversion Phosphor Applied in Temperature Sensing and Anti-Counterfeiting

Crystalline BaWO4 was synthesized by preparing a precursor by co-precipitation followed by heat treatment at 800 °C. For use as up-conversion phosphor materials, rare earth ions Er3+ and Yb3+ were co-doped. In the synthesized BaWO4:[Er3+]/[Yb3+], a strong peak from the (112) phase, the main peak, could be observed in the XRD analysis and had a tetragonal structure. The lattice constant was changed by the rare earth doping, and when the sample was excited at 980 nm, green light emission was confirmed. The luminescence intensity changed according to the change in the amount of Er3+, a rare earth ion, and the luminescence intensity increased strongly as the laser power of the excitation wavelength increased. This is a phenomenon caused by the two-photon effect, and it was possible to confirm the characteristics of the up-conversion phosphor. To investigate the use of the synthesized phosphor for temperature sensors and anti-counterfeiting, a flexible composite and ink were made, respectively. As the temperature increased, the luminous intensity of the flexible composite was weakened, and the produced ink was difficult to observe with the naked eye when applied to banknotes, but when illuminated with a 980 nm laser, the green label could be seen.

Features of electronic phase separation in multiferroic ErMn2O5

The effect of rare-earth ions Er3+, which has a large orbital contribution to the magnetic moment, on the phase transitions and states of the phase separation nanoregions has been studied in multiferroic ErMn2O5. These nanoregions are semiconductor heterostructures formed due to self-organization processes in the ErMn2O5 matrix. A significant effect of Er3+ ions, the moments of which are rigidly oriented along the c axis of the crystal, on the magnetic dynamics, heat capacity, and multiferroic properties of superlattices layers in a wide temperature range of 5 ÷ 300 K has been revealed.

Near-IR Luminescence of Rare-Earth Ions (Er3+, Pr3+, Ho3+, Tm3+) in Titanate-Germanate Glasses under Excitation of Yb3.

Inorganic glasses co-doped with rare-earth ions have a key potential application value in the field of optical communications. In this paper, we have fabricated and then characterized multicomponent TiO2-modified germanate glasses co-doped with Yb3+/Ln3+ (Ln = Pr, Er, Tm, Ho) with excellent spectroscopic properties. Glass systems were directly excited at 980 nm (the 2F7/2 → 2F5/2 transition of Yb3+). We demonstrated that the introduction of TiO2 is a promising option to significantly enhance the main near-infrared luminescence bands located at the optical telecommunication window at 1.3 μm (Pr3+: 1G4 → 3H5), 1.5 μm (Er3+: 4I13/2 → 4I15/2), 1.8 μm (Tm3+: 3F4 → 3H6) and 2.0 μm (Ho3+: 5I7 → 7I8). Based on the lifetime values, the energy transfer efficiencies (ηET) were estimated. The values of ηET are changed from 31% for Yb3+/Ho3+ glass to nearly 53% for Yb3+/Pr3+ glass. The investigations show that obtained titanate–germanate glass is an interesting type of special glasses integrating luminescence properties and spectroscopic parameters, which may be a promising candidate for application in laser sources emitting radiation and broadband tunable amplifiers operating in the near-infrared range.

Phase transitions and phase transformations in the phase separation nanoregions in ErMn-=SUB=-2-=/SUB=-O-=SUB=-5-=/SUB=- multiferroics

The effect of the rare-earth ion Er3+, which has a large orbital contribution to the magnetic moment, were studied to phase transitions and phase transformations of 2D nanoregions of phase separation in the ErMn2O5 multiferroic. These nanoregions are the semiconductor heterostructures (superlattices) and are formed due to self-organization processes in the ErMn2O5 matrix. Significant effect of Er3+ ions, the moments of which are rigidly oriented along the c axis of the crystal, on the magnetic dynamics, heat capacity and multiferroic properties of layers superlattises was found at a wide temperature range 5-300 K in ErMn2O5 multiferroics. Keywords: multiferroic, 2D phase separation nanoregions, semiconductor-heterostructures, superlattices, phase transitions, phase transformations.

Phase transitions and phase transformations in the phase separation nanoregions in ErMn-=SUB=-2-=/SUB=-O-=SUB=-5-=/SUB=- multiferroics

The effect of the rare-earth ion Er3+, which has a large orbital contribution to the magnetic moment, were studied to phase transitions and phase transformations of 2D nanoregions of phase separation in the ErMn2O5 multiferroic. These nanoregions are the semiconductor heterostructures (superlattices) and are formed due to self-organization processes in the ErMn2O5 matrix. Significant effect of Er3+ ions, the moments of which are rigidly oriented along the c axis of the crystal, on the magnetic dynamics, heat capacity and multiferroic properties of layers superlattises was found at a wide temperature range 5-300 K in ErMn2O5 multiferroics. Keywords: multiferroic, 2D phase separation nanoregions, semiconductor-heterostructures, superlattices, phase transitions, phase transformations.

Mid-Infrared Luminescence of the High Stability Perovskite CsPb1-xErxBr3-ZrF4-BaF2-LaF3-AlF3-NaF Fluoride Glass.

Perovskites have been studied because of their adjustable wavelength range, high color purity, and wide color gamut. However, they still face some problems such as poor stability and insufficient infrared luminescence. The perovskite glass can improve the stability and luminescence properties of the perovskite. In this paper, a highly stable CsPb1-xErxBr3-ZBLAN fluoride glass with mid-infrared and visible light emission was prepared. The ZBLAN fluoride glass has good inertness, which can improve the stability of the CsPb1-xErxBr3 perovskite. The CsPb1-xErxBr3-ZBLAN fluoride glass can prevent the perovskite from being destroyed by water, oxygen, and laser. The Er3+ replaces Pb2+ to bond with Br- to become the luminescent center of the CsPb1-xErxBr3-ZBLAN perovskite glass, which extends the luminescence to the mid-infrared region. In addition, its luminescent intensity is significantly higher than those of the ZBLAN-Er glass and CsPb1-xErxBr3 perovskite. After irradiation with a 365 nm UV lamp for 13 h, the luminescence intensity of the CsPb1-xErxBr3-ZBLAN perovskite glass decreases only by 10%. The EDS spectrum shows that the elements of the CsPb1-xErxBr3 perovskite are uniformly distributed in the glass matrix. The X-ray diffraction spectrum shows that the sample has both the CsPb1-xErxBr3 perovskite phase and the glass phase. This indicates that CsPb1-xErxBr3 is well crystallized in the ZBLAN glass matrix. The three parameters calculated by the Judd-Ofelt theory show that the CsPb1-xErxBr3 perovskite can increase the covalency and asymmetry around the rare earth ion Er3+. The transmission electron microscope can clearly see the morphological structure of the CsPb1-xErxBr3 perovskite in the ZBLAN glass matrix. The infrared Fourier transform spectroscopy shows that the sample has lower phonon energy. This proves that the sample has good infrared luminescence characteristics. Finally, the visible and infrared light sources were prepared. Under the irradiation of the 365 nm ultraviolet lamp and 980 nm laser, the perovskite glass produces green light and infrared emission.

Expedient Red Emitting and Transparency Dual Modulation in KNN-Based Transparent Ceramics via Sensitive Photothermochromic Behavior

An up-conversion luminescence (UCL) transparent ferroelectric oxide (KNN) introduced by rare-earth ions (Er3+ and Bi3+) has been demonstrated to exhibit a unique, high-purity, red emitting, high transparency, reversible, photothermochromic (PTC) reaction. And, its associated transmittance/red emitting modulations are realized via the continuous alternating of UV light irradiation and heat treatment (200 °C). The effects of the phase structure, microstructure, and oxygen vacancy defects on their optical transmittances and the corresponding optical modulation based on PTC reaction at different sintering temperatures were systematically studied. Because of the sufficiently small grain size, dense structure, and appropriate concentration of oxygen vacancy defects, excellent optical transparency (∼70%, at 900 nm) and moderate PTC modulation contrast (ΔAbs = 13.9%, ΔR = 48.9%) are obtained in KNNEB-1155. The decreased and increased transmittance/red emitting can represent two pairs of “off” and “on” codes, which makes the red-emitting KNNEB transparent ceramics very competitive in the application of multifunctional transparent sustainable warning equipment and optical storage materials.

Фазовые переходы и фазовые превращения в нанообластях фазового расслоения в мультиферроике ErMn-=SUB=-2-=/SUB=-O-=SUB=-5-=/SUB=-

The effect of the rare-earth ion Er3+, which has a large orbital contribution to the magnetic moment, were studied to phase transitions and phase transformations of 2D nanoregions of phase separation in the ErMn2O5 multiferroic. These nanoregions are the semiconductor heterostructures (superlattices) and are formed due to self-organization processes in the ErMn2O5 matrix. Significant effect of Er3+ ions, the moments of which are rigidly oriented along the c axis of the crystal, on the magnetic dynamics, heat capacity and multiferroic properties of layers superlattises was found at a wide temperature range 5 K - 300 K in ErMn2O5 multiferroics.

Largely enhanced luminescence intensity and improved optical temperature sensing properties in CaWO4-La2(WO4)3: Er3+, Yb3+ via regulating cations composition.

High temperature sensing sensitivity and luminescence intensity of phosphors are crucial factors for excellent optical temperature sensing performance. Based on material design, the pure phase and two-phase solid solutions were prepared by regulating the relative content of cations Ca2+ and La3+ in CaWO4–La2(WO4)3, respectively. The up-conversion luminescence (UCL) and optical temperature sensing performance of rare earth ions Er3+/Yb3+ co-doped CaWO4–La2(WO4)3 were studied. As guided by regulating cation composition through partial substituting Ca2+ ions by La3+ ions, the UCL intensity of two-phase solid solutions at 552 nm is much higher than that of pure phase material. The UCL intensity of 0.2La2(WO4)3–0.8CaWO4: 1%Er3+, 5%Yb3+ is as 33.5 times as that of CaWO4: 1%Er3+, 5%Yb3+ material. More importantly, the high temperature sensing sensitivity (0.01026 K−1) is achieved in a wider temperature range 83–683 K in optimal UCL material 0.2La2(WO4)3–0.8CaWO4: 1%Er3+, 5%Yb3+. It is suggested that material design theory can be used as a powerful tool to accelerate discovery of novel optical temperature sensing materials, with implications even for the design of other optoelectronic materials.

Dual-mode luminescence tuning of Er[formula omitted] doped Zinc Sulfide piezoelectric microcrystals for multi-dimensional anti-counterfeiting and temperature sensing

In this study, a multi-color and multi-mode luminescence material has been developed for anti-counterfeiting and temperature sensing. The rare earth ions Er3+ are selected as the luminescent center to be doped in the piezoelectric material ZnS. The prepared samples can generate multi-color (orange–yellow–green) and multi-mode (upconversion/down-shifting/energy transfer) emission through the energy transitions of lanthanide ions in the ZnS host. When the excitation wavelength or the temperature is selected to be different, the luminous color is obviously different due to different mode emission. Therefore, multiple anti-counterfeiting of a single compound can be realized, the security degree of the anti-counterfeiting can be improved and overcome the defect of the general fluorescent material in a single light-emitting mode. The work will establish experimental basis for the design and development of a new high-integration functional luminescence material, and is expected to use the developed materials in the fields of optical anti-counterfeiting and information encryption.

Incorporation of erbium ions into thin-film lithium niobate integrated photonics

As an active material with favorable linear and nonlinear optical properties, thin-film lithium niobate has demonstrated its potential in integrated photonics. Integration with rare-earth ions, which are promising candidates for quantum memories and transducers, will enrich the system with new applications in quantum information processing. Here, we investigate the optical properties at 1.5 μm wavelengths of rare-earth ions (Er3+) implanted in thin-film lithium niobate waveguides and micro-ring resonators. Optical quality factors near a million after post-annealing show that ion implantation damage can be repaired. The transition linewidth and fluorescence lifetime of erbium ions are characterized. The ion-cavity coupling is observed through a Purcell enhanced fluorescence from which a Purcell factor of 3.8 ± 0.5, compared with waveguide lifetime, is extracted. This platform is compatible with top-down lithography processes and leads to a scalable path for controlling spin-photon interfaces in photonic circuits.

Upconversion/downconversion luminescence of color-tunable Gd2O3:Er3+ phosphors under ultraviolet to near-infrared excitation

Multicolored luminescence tuning in a single rare earth ion (Er3+) activated rare earth oxide phosphors were achieved among green to red colors. The emission bands in visible light region corresponding to the transitions between 4F7/2 → 4I15/2 (487 nm), 2H11/2 → 4I15/2 (525 nm), 4S3/2 → 4I15/2 (550 nm) and 4F9/2 → 4I15/2 (667 nm) were demonstrated by luminescence spectroscopy under excitations at 379 nm and 980 nm. The dependence of upconversion/downconversion luminescence intensity on the firing temperature and Er3+ concentration were investigated, which is useful to tailor the color chromaticity coordinates under varied excitation wavelengths by adjusting the experimental conditions.

Tungsten sodium phosphate glasses doped with trivalent rare earth ions (Eu3+, Tb3+, Nd3+ and Er3+) for visible and near-infrared applications

Tungsten-phosphate glasses doped with different rare earth ions (Er3+, Eu3+, Nd3+ and Tb3+) were obtained by the conventional melt-quenching technique. At high amounts of tungsten oxide (>50 mol%), the tungsten-phosphate glasses are only translucent due to reduced W5+ species. However, the transparency of the glasses is significantly increased by the addition of Sb2O3 - as an oxidating agent which promotes the conversion of W5+ into W6+. FTIR spectra allowed identification of absorption bands corresponding to phosphate structural groups and tungsten units in the 500–1300 cm−1 spectral region. The optical absorption, luminescence excitation and emission spectra were collected and Judd-Ofelt analysis was carried out for selected samples. It is observed that by increasing the amount of WO3, the lifetime of the Er3+ NIR emission increases as well as the branching ratio of Eu3+ emission band at 610 nm, respectively, due to lowering of the average phonon energy of the glassy system and increasing of the site asymmetry around the rare earth ions. Details on the photophysics of these glasses, including upconversion and the analysis of radiative properties via Judd-Ofelt calculations are given and discussed as a function of structural variations and dopant ion concentrations.

The Magnetic, Electrical and Optical Properties of Rare Earth Er3+ Doped Lead Borate Glass

Owing to the unique electronic structure of rare earth elements, we address in this paper the magnetic, electrical and optical properties of a prepared lead borate glass of composition (mol.%) 70PbO·30B2O3. The glass is doped with different ErCl3 contents. A vibrating-sample magnetometer was used to characterize the magnetic properties. Increasing the additive concentration led to an increase in the saturation magnetization without significant effects on the coercivity. Optical reflectance spectra of the doped glasses revealed the development of absorption bands as a result of Er3+ intra-configurational (f–f) transitions. The calculated allowed direct energy gap was found to increase monotonically with increasing dopant concentration. The results of the ac conductivity showed a decrease in the activation energy values with increasing frequency and an increase in the ac conductivity values with increasing temperature, which mimics the semiconducting behavior. The incorporation of the rare earth ion (Er3+) facilitated the electronic conduction due to the increase of the non-bridging oxygen units. Increasing the dopant concentration led also to the participation of the ionic conductions. However, further increase of ErCl3 (above 1 mol.%) caused a decrease in the conductivity. Samples with dopant content up to 1 mol.% ErCl3 are accompanied by a high dielectric constant value of about 40. It can be concluded that samples doped with 1 mol.% ErCl3 or less can be used as energy storage material in electronic devices, whereas glass samples with higher dopant content can be used for magnetic applications.

Towards long-distance quantum networks with superconducting processors and optical links

We design a quantum repeater architecture, necessary for long distance quantum networks, using the recently proposed microwave cat state qubits, formed and manipulated via interaction between a superconducting nonlinear element and a microwave cavity. These qubits are especially attractive for repeaters because in addition to serving as excellent computational units with deterministic gate operations, they also have coherence times long enough to deal with the unavoidable propagation delays. Since microwave photons are too low in energy to be able to carry quantum information over long distances, as an intermediate step, we expand on a recently proposed microwave to optical transduction protocol using excited states of a rare-earth ion (Er3+) doped crystal. To enhance the entanglement distribution rate, we propose to use spectral multiplexing by employing an array of cavities at each node. We compare our achievable rates with direct transmission and with two other promising repeater approaches, and show that ours could be higher in appropriate regimes, even in the presence of realistic imperfections and noise, while maintaining reasonably high fidelities of the final state. Thus, in the short term, our work could be directly useful for secure quantum communication, whereas in the long term, we can envision a large scale distributed quantum computing network built on our architecture.

Upconversion emission of the GaN nanocrystals doped with rare earth ions

The crystalline powders of GaN doped with pairs of rare earth ions Er3+-Yb3+ or Ho3+-Yb3+, were synthesized with using the combustion and ammonolysis procedures. Spectroscopic properties of the investigated GaN nanosized samples were measured and analyzed. As excitation sources, the laser diodes operating at 808 and 975 nm were used. The upconversion emissions in the visible range were observed for used laser excitations. The upconversion emission properties depend on the synthesis conditions and the concentration ratio of the doped lanthanide ions.

Up-Conversion Photoluminescence of Sol–Gel Derived CaY2O4 Powders Under 980 nm Excitation

Up-conversion is an anti-stokes process that can convert near-infrared light into visible light. Besides the requirement of high optical conversion efficiency, the thermochemical stability of the host materials is critical for in practical applications, and a stable oxide host material is optimal. CaY₂O₄ follows the same ordered structure of CaFe₂O₄, which is composed of an (R₂O₄)2- (R = rare earth metal) framework of double octahedral moieties with rare earth ions residing within the framework. CaY₂O₄ is a promising host material due to its favorable characteristics such as high chemical and thermal stability, low-phonon energy, and environment friendliness. Rare earth ion (Er3+ and Yb3+)-doped nano-crystalline phosphors were prepared by a sol-gel process. The synthesized sample was characterized by X-ray diffraction analysis and the crystallite size was confirmed by Scherrer's formula and transmission electron microscopy. The surface morphology of the powders was determined by scanning electron microscopy. X-ray diffraction patterns confirmed their pure orthorhombic structure after annealing at 1,200 °C and the morphology of particles was found to be a nearly spherical shape with a diameter of the order of ~100 nm. Photoluminescence properties of the powders were measured by exciting the samples with a 980 nm diode laser at room temperature. Under the 980-nm laser excitation, the green and red up-conversion emissions were observed at around 520- 540 nm, 540-570 nm and 640-680 nm, which, are attributed to the transitions of ²H11/2 →⁴I15/2, ⁴S3/2 →⁴I15/2 and ⁴F9/2 →⁴I15/2 of Er3+ ions, respectively. The up-conversion intensity as a function of laser power shows that the up-conversion mechanism corresponding to green and red emissions occurs via a two-photon process.