Search Results (179)

Rare-earth elements (REEs), which include the entire lanthanide series together with scandium and yttrium, have unique electronic configurations and coordination chemical properties that provide them with special magnetic, optical, and redox abilities. Generally used for diagnostic imaging and theranostic applications, increasing evidence emphasizes their potential as direct anticancer agents. This review aims to present a thorough investigation of the studies published in the last ten years that focus on the intrinsic anticancer properties of REE-based molecular complexes and nanostructures, without discussing their recognized imaging functions. Rare-earth compounds exhibit selective cytotoxicity against malignant cells via mechanisms that mainly include modulations in the generation of reactive oxygen species, mitochondrial dysfunctions, interaction with DNA molecules, apoptosis, and ferroptosis induction, as well as radiosensitization. Molecular complexes that are based on the trivalent coordination chemistry of REEs enable them to target biomolecules like DNA and serum albumin. Nanostructured systems, on the other hand, render tumors more responsive to treatment by improving the cellular uptake, enabling surface functionalization, and controlling ROS generation. Terbium, thulium, yttrium, scandium, ytterbium, cerium, erbium, dysprosium, and europium show different levels of anticancer activity in both in vitro and in vivo cancer models. They often exert more toxicity in tumor cells than in normal tissues, thus exhibiting selective anticancer effects. The findings collectively underscore the therapeutic potential of REE-based compounds as novel metal-based anticancer agents and advocate for additional mechanistic and translational research to enhance their clinical applicability. Full article

Lead borophosphate zinc barium glass systems doped with different concentrations of Dy₂O₃ (0.5–2.0 mol%) were fabricated using the traditional melt-quenching method. The non-crystalline nature of the synthesized glass samples was verified through X-ray diffraction (XRD) analysis, which exhibited the characteristic absence of sharp diffraction peaks. Morphological, structural, and vibrational properties were analyzed using scanning electron microscopy (SEM) and Fourier infrared transmission (FTIR) spectroscopy. Optical absorption, emission, and decay lifetime observations were recorded to evaluate the luminescence behavior of Dy³⁺ ions. Judd–Ofelt parameters (Ω₂, Ω₄, and Ω₆) were evaluated from the optical absorption spectra of all the prepared glass samples. The emission spectra revealed three dominant transitions in the visible region corresponding to the ⁴F_9/2 ⟶ ⁶H_15/2 (blue ~ 484 nm), ⁴F_9/2 ⟶ ⁶H_13/2 (yellow ~ 574 nm), and ⁴F_9/2 ⟶ ⁶H_11/2 (~663 nm) transitions. Radiative characteristics, including radiative transition probability (A_R), radiative lifetime (τ_R), and branching ratio (β_R), were calculated from the emission spectra. Among the investigated compositions, the host glass embedded with 1.0 mol% Dy₂O₃ demonstrated the maximum emission intensity was observed along with superior quantum efficiency (η = 91.68%). The chromaticity coordinates for this composition (x = 0.33, y = 0.41) are positioned close to the white-light region in the CIE 1931 chromaticity diagram. These findings suggest that incorporating 1.0 mol% of Dy₂O₃ yields the highest luminescence efficiency, making the present glass system a promising candidate for white-light-emitting and photonic device applications. Full article

Rare earth elements are indispensable for a wide range of advanced technologies, which underscores their strategic importance. This study investigates the kinetics of extracting heavy rare earth elements—lutetium, thulium, yttrium, erbium, and dysprosium—from industrial phosphoric acid solutions generated during apatite processing. A comparative approach using both solvent and solid-phase extraction with di-(2-ethylhexyl)phosphoric acid (D2EHPA) was applied to elucidate the underlying mechanisms. Optimal solvent extraction parameters ($V_{aq}:V_{org}$ = 2:1, ${\phi }_{D2EHPA}$ = 0.2, 298 K, stirring at 350 rpm) achieved efficiencies exceeding 85%. Efficient solid-phase recovery was attained under mild conditions (298 K, m:V = 1:10, shaking at 100 opm). The rate-limiting steps were identified as diffusion-controlled for solvent extraction, governed primarily by agitation intensity, and as a mixed external–internal diffusion regime for solid-phase extraction. Calculated activation energies for each element corroborate these findings. Full article

Multicomponent mixed lanthanide oxide (MMLO) nanoparticles possess considerable potential as multimodal imaging agents because they integrate diverse excellent optical and magnetic properties within a single nanoparticle. Herein, we present triply and quadruply mixed lanthanide oxide nanoparticles, namely, gadolinium (Gd)/dysprosium (Dy)/europium (Eu) oxide (GDEO), Gd/Dy/terbium (Tb) oxide (GDTO), and Gd/Dy/Eu/Tb oxide (GDETO) nanoparticles. Gd³⁺ can strongly induce positive (T₁) contrast in magnetic resonance imaging (MRI), Dy³⁺ and Tb³⁺ can generate negative (T₂) contrast in MRI, and Eu³⁺ and Tb³⁺ emit visible photons that are applicable to fluorescence imaging (FI). All the nanoparticles were grafted with hydrophilic, biocompatible polyacrylic acid (PAA) to enhance colloidal stability and biocompatibility and further grafted with small amounts of an organic photosensitizer, 2,6-pyridinedicarboxylic acid (PDA), to obtain a high absolute fluorescent quantum yield (QY) with an extended fluorescent lifetime (τ). All PAA-MMLO and PAA/PDA-MMLO nanoparticles exhibited nearly monodispersed particle-size distributions with average particle diameters of ~2 nm and displayed considerably higher longitudinal (r₁) and transverse (r₂) water proton spin relaxivities than commercial molecular MRI contrast agents. The PAA/PDA-GDEO, PAA/PDA-GDTO, and PAA/PDA-GDETO nanoparticles exhibited high absolute QYs of 45, 29, and 61%, respectively, and long τ values of 1–2 ms, making them suitable for time-delayed noise-free fluorescence signal detection. These findings confirm the high potential of PAA-MMLO nanoparticles as T₁ and/or T₂ MRI contrast agents and PAA/PDA-MMLO nanoparticles as both T₁ and/or T₂ MRI and FI agents. Full article

Dysprosium is one of the most critical elements for global economies due to its essential role in the green energy transition. Although it is added in small quantities as an alloying element, dysprosium plays a crucial role in NdFeB magnets used in wind turbines and industrial motors. On the other hand, the limited resources and production capacity of dysprosium contribute to supply shortages and raise concerns about its long-term availability. Therefore, there is a need for efficient techniques that will enable the recovery of dysprosium from secondary materials to bridge the gap between supply and demand while addressing the risks associated with securing a stable supply. This review focuses on (bio)hydrometallurgical and solvometallurgical methods for recovering dysprosium from key secondary sources such as spent NdFeB magnets, phosphogypsum, and coal ash. Although these wastes do not always contain high concentrations of dysprosium, they can have a simpler elemental composition compared to primary sources (a few tens or hundreds of ppm Dy) and are more readily available. Spent NdFeB magnets, with a few percent Dy, show the most promise for recycling. In contrast, coal fly ashes (with several ppm Dy), although widely available, bind dysprosium in an inert phase, requiring substantial pretreatment to enhance the release of the desired element. Phosphogypsum, while not yet a significant source of dysprosium (several ppm Dy), is increasingly recognized as a potential source for other rare earth elements. Although conventional hydrometallurgical methods are commonly used, these are typically unselective for dysprosium recovery, whereas unconventional solvometallurgical approaches show preferential extraction of dysprosium over base metals. Full article

In this study, nanocrystalline dysprosium oxide (Dy₂O₃) thin films were deposited on sapphire and quartz glass substrates by an electron beam evaporation technique to comparatively evaluate the influence of substrate type on their structural and optical properties. X-ray diffraction (XRD) confirms that all films exhibit a polycrystalline nature and possess a cubic-type structure. The Debye–Scherrer equation was used to determine the average crystallite size and it was found that the film deposited on quartz glass substrate is slightly larger than the film deposited on the sapphire substrate. Scanning electron microscopy (SEM) revealed a granular morphology for the sapphire film and a more compact, pore-free surface for the quartz film. Spectroscopic ellipsometry (SE) and UV-Vis spectrophotometry were employed to extract the optical constants and reflectance behavior, respectively. The film on sapphire exhibited a lower refractive index, higher extinction coefficient, and reduced reflectance, confirming its enhanced anti-reflective performance. The study provides new insights into how the substrate affects the optical properties of Dy₂O₃ thin films. This study demonstrates that sapphire is a more suitable substrate for enhanced anti-reflective and optoelectronic applications. Full article

Lanthanide-based single-molecule magnets (Ln-SMMs) showing stimuli-responsive changes in photoluminescence (PL) and magnetic properties are attractive for their potential applications in information storage and molecular devices. In this work, we report two mononuclear complexes, namely, Dy(SCN)₂(NO₃)(Cl-depma)₂(4-hpy)₂ (Dy-Cl) and Dy(SCN)₂(NO₃)(Br-depma)₂(4-hpy)₂ (Dy-Br), where X-depma represents 10-X-9-diethylphosphinomethylanthracene (X = Cl, Br) and 4-hpy is 4-hydroxypyridine. Both contain face-to-face π-π-interacted anthracene rings and exhibit yellow-green excimer emission. Unlike the other related Dy–anthracene complexes without a halogen substituent, Dy-Cl and Dy-Br cannot undergo photocycloaddition reaction under UV-light irradiation. However, they exhibited remarkable grinding-induced changes in luminescence. Magnetic studies revealed that Dy-Cl and Dy-Br show SMM behavior under zero dc field with the effective energy barriers (U_eff/k_B) of 259 K and 264 K, respectively. We also investigated the effect of pressure on the magnetic properties of Dy-Br and observed a reduction in the magnetization value, narrowing of the butterfly-shaped hysteresis loop, and acceleration of the magnetic relaxation under 1.09 GPa. The results demonstrate that introducing a halogen substituent into an anthracene group may pose significant influences on the photophysical and photochemical properties of the complexes. In addition, pressure may be a promising external stimulus to modulate the PL and SMM behaviors of Dy–anthracene complexes. Full article

The electrochemical properties of the dysprosium-doped strontium cobaltite SDC (Sr_0.8Dy_0.2CoO_3−δ) were evaluated for possible application as pseudocapacitor electrode materials. Dense perovskite SDC ceramics were prepared using standard solid-state synthesis techniques. The SDC sample was characterized using XRD, structural analysis, SEM/EDS, and simultaneous thermal analysis. The electrochemical performance of the electrode was estimated in 3M KOH in a standard electrochemical cell for corrosion studies using cyclic voltammetry, impedance spectra, galvanostatic charge/discharge, and long-term cycling stability. The study demonstrated that the SDC exhibits high oxygen mobility and has the ability to release or incorporate oxygen from the gas phase. This process leads to the formation of structural anion vacancies without compromising the structural integrity. The SDC electrode demonstrates a specific capacitance of approximately 500 F/m² and exhibits satisfactory cyclability. Electrochemical treatment in charge–discharge cycles has been shown to result in the formation of a thin strontium-depleted layer on the electrode surface. The observed behavior is believed to be caused by a high concentration of oxygen vacancies, which is consistent with oxygen intercalation into the perovskite structure. The present study suggests that rare earth-doped strontium cobaltite may serve as a prospective precursor for electrode material in supercapacitors. Full article

Dy³⁺:InF₃ fiber shows promise for 4.4 μm mid-infrared lasing, but the much shorter lifetime of its upper laser level compared to the lower level causes inevitable self-termination. While cascade 4.4 μm/3 μm lasing has been proposed as a potential solution, this method faces complex configuration and an extremely high pump threshold (>30 W under continuous-wave operation), rendering it impractical for high-power use, especially given InF₃’s soft-glass nature. To address the self-termination challenge and enable the low-threshold, high-efficiency lasing, this study proposes, for the first time to our knowledge, a dual-wavelength cascade-pumping scheme utilizing 2.8 μm and 2.4 μm pumps. Numerical simulations demonstrate that the dual-wavelength cascade-pumped Dy³⁺:InF₃ fiber laser exhibits an optical-to-optical efficiency of up to 18.4% and a maximum slope efficiency of 38.5%. The total pump threshold is as low as 5.4 W, remarkably lower than that required by the cascade lasing approach. This work provides a viable solution and design guidelines for the development of 4 μm-class mid-infrared fiber lasers. Full article

This work shows that inverse Judd–Ofelt (JO) analysis of relative absorption spectra, anchored by a single lifetime, provides JO parameters and radiative rates without absolute calibration. The method is applied to Er³⁺, Dy³⁺, and Sm³⁺ in a compositionally identical oxyfluoride glass. Three well-resolved ground-state 4f–4f absorption bands were selected. After baseline removal and wavenumber-domain integration, their normalized strengths S_rel,k (k = 1, 2, 3; k∈S) define a 3 × 3 system solved by non-negative least squares to obtain the anchor-independent ordering (Ω₂:Ω₄:Ω₆). Absolute scaling uses a single lifetime anchor. We report lifetime-scaled Ω_t and A_rad, and the normalized fractions p_k within the selected triplets; as imposed by the method, the anchor-independent ordering (Ω₂:Ω₄:Ω₆) is analyzed, while absolute A_rad and Ω_t scale with τ_ref. The extracted parameters fall within the expected ranges for oxyfluoride hosts and reveal clear ion-specific trends: Ω₂ follows Dy³⁺ > Er³⁺ > Sm³⁺ (site asymmetry/hypersensitive response), while the ordering Ω₄ > Ω₆ holds across all ions (oxide-rich networks). Er³⁺ exhibits the largest Ω₄ and the smallest Ω₆, indicative of pronounced medium-range “rigidity” with suppressed long-range polarizability; Sm³⁺ shows the lowest Ω₂ (more symmetric/less covalent coordination); and Dy³⁺ the highest Ω₂ (strong hypersensitive behavior). Uncertainty was quantified by Monte Carlo resampling of the preprocessing steps, yielding compact 95% confidence intervals; the resulting JO-parameter trends (Ω₂, Ω₄, Ω₆) and normalized f_k fractions reproduce the characteristic spectroscopic behavior known for each ion. This method enables quantitative JO outputs from uncalibrated spectra, allowing direct spectroscopic comparisons and quick screening when only relative absorption data are available. Full article

The limited availability of powerful, tunable, and reliable mid-infrared sources has historically prevented their widespread adoption in spectroscopy applications, even if most greenhouse gases’ fundamental absorption lines are found in this region of the electromagnetic spectrum. However, both mid-infrared fiber lasers and ICLs have enjoyed substantial growth in available output powers in recent years. Since the two technologies have complementary benefits, combining them could prove to be an interesting avenue to explore toward the development of a powerful, easily tunable, and narrow linewidth mid-infrared source. We report what we believe to be the first demonstration of fiber amplification of a distributed feedback interband cascade laser (DFB-ICL) operating in the mid-infrared. The system, based on an in-band pumped dysprosium-doped fluoride fiber amplifier, yields 10 dB of gain and up to 30 mW of output power at 3240 nm. We believe this is an important milestone toward power scaling of single-mode, single-frequency, and rapidly tunable mid-infrared laser sources suitable for advanced gas spectroscopy. Full article

To study the adsorption of lanthanide (Ln) atoms on graphene containing a Stone–Wales defect, we used a cluster model (SWG) and performed calculations at the PBE-D2/DNP level of the density functional theory. Our previous study, where the above combination was complemented with the ECP pseudopotentials, was only partially successful due to the impossibility of calculating terbium-containing systems and a serious error found for the SWG complex with dysprosium. In the present study we employed the DSPP pseudopotentials and completely eliminated the latter two failures. We analyzed the optimized geometries of the full series of fifteen SWG + Ln complexes, along with their formation energies and electronic parameters, such as frontier orbital energies, atomic charges, and spins. In many regards, the two series of calculations show qualitatively similar features, such as roughly M-shaped curves of the adsorption energies and trends in the changes in charge and spin of the adsorbed Ln atoms, as well as the spin density plots. However, the quantitative results can differ significantly. For most characteristics we found no evident correlation with the lanthanide contraction. The only dataset where this phenomenon apparently manifests itself (albeit to a limited and irregular degree) is the changes in the closest Ln^…C approaches. Full article

This study reports an investigation of the synergistic extraction of dysprosium (Dy(III)) from aqueous media using a low-concentration, binary carrier mixture of Cyanex 272 and D2EHPA within an emulsion liquid membrane (ELM). Within the tested formulations, the one containing 0.42% (w/w) Cyanex 272 and 0.28% (w/w) D2EHPA yielded the best results. The impact of process factors that maximize recovery efficiency and minimize emulsion breakdown was also examined. A Span 80 loading of 0.75% (w/w) achieved 97.5% extraction with minimal breakage (less than 2.1%). An external phase pH of 5.8 achieves an optimal balance of high-throughput Dy(III) recovery and membrane stability; 0.2 N HNO₃ as the stripping phase strikes the optimal balance, providing strong initial uptake with minimal emulsion degradation. As the initial Dy(III) loading increases, extraction efficiency decreases. Increasing the temperature from 15 to 45 °C accelerates mass transfer, achieving near-complete extraction in under 15 min. However, above 45 °C, emulsion breakage spikes, causing a collapse in efficiency. Similarly, increasing NaCl levels suppresses Dy(III) uptake and promotes coalescence. This reduces recovery from seawater to just over 70%. Nevertheless, the balanced mineral content of Zamzam water preserves emulsion integrity and enables 100% extraction. The activation energy was found to be 26.16 kJ/mol, suggesting that mass transfer, rather than the chemical reaction at the interface, controls the process. The results of this study highlight the synergistic efficiency advantage of the ELM system at lower carrier concentrations, even in complex water sources. Full article

To develop single molecule magnets, a dinuclear complex [Dy₂(HOBQ)₄Cl₆] (1) was prepared from the reaction of DyCl₃ with benzo[h]quinolin-10-ol (HOBQ). Each Dy(III) ion shows a compressed octahedral geometry and the two Dy(III) ions in 1 are bridged by two Cl⁻ ligands to construct a dinuclear structure with the four HOBQ ligands on the axial positions and six Cl⁻ ligands in the equatorial plane. Magnetic measurements showed that complex 1 is a field-induced single molecule magnet having an obvious magnetic hysteresis loop with an energy barrier of 71(2) K. These experimental results are corroborated by the ab initio complete active space self-consistent field (CASSCF) calculations which also interpret the magneto-structural correlation. It is a typical example to achieve Dy(III) SMM through regulating coordination geometry, i.e., lengthening equatorial coordination bonds and shortening axial ones to form a compressed octahedral geometry. Full article

Plugs of lignite coal from multiple formations were subjected to a series of tests to determine the amount of rare-earth elements (REEs) to be extracted from coal in an in situ mining operation. These tests were used to determine if extraction of REEs and other critical minerals in an in situ environment would be possible for future attempts as an alternative to extraction mining. The tests involved subjecting whole lignite coal plugs from the Twin Butte coal seams in North Dakota to flow-through tests of water, and concentrations of 1.0 M ammonium nitrate, 1.0 M and 1.5 M sulfuric acid, and 1.0 M and 1.5 M hydrochloric acid (HCl) solvents at different concentrations and combinations. The flow-through testing was conducted by alternating the solvent and water flow-through to simulate an in situ mining scenario. The samples were analyzed for their concentrations of REEs (lanthanum [La], cerium [Ce], praseodymium [Pr], neodymium [Nd], samarium [Sm], europium [Eu], gadolinium [Gd], terbium [Tb], dysprosium [Dy], holmium [Ho], erbium [Er], thulium [Tm], ytterbium [Yb], lutetium [Lu], yttrium [Y], and scandium [Sc], as well as germanium [Ge] and cobalt [Co], manganese [Mn], nickel [Ni], and barium [Ba]). Results from the testing showed that REEs were extracted in concentrations that were on average higher using sulfuric acid (8.9%) than with HCl (5.8%), which had a higher recovery than ammonium nitrate. Tests were performed over a standard time interval for comparison between solvents, while a second set of testing was done to determine recovery rates of REEs and critical minerals under certain static and constant flow-through times to determine extraction in relation to time. Critical minerals had a higher recovery rate than the REEs across all tests, with a slightly higher recovery of light REEs over heavy REEs. Full article