Two europium(III) coordination compounds based on tri- and tetracarboxybenzene ligands (H3btc and H4btec) and 1,10-phenanthroline were synthesized and thoroughly characterized. Both compounds display characteristic Eu3+ photoluminescence with high quantum yields (22% and 41%). Cathodoluminescence studies revealed bright and stable emission up to 9 kV, with the btec-based compound exhibiting higher intensity and greater resistance to electron-beam-induced degradation. Most notably, thin films of the btec compound demonstrate robust X-ray-induced luminescence (XRL) under 40-90 kV excitation. XRL intensity increases linearly with both voltage and current, and remains spectrally stable over prolonged exposure, with minimal performance loss. These results highlight the role of ligand structure and compound stability in high-energy-excited luminescence and suggest promising applications of Eu3+-polycarboxylate frameworks in X-ray sensing and imaging devices.

Tetradentate phenanthroline-based ligands have demonstrated ability to efficiently extract uranium(VI) from nitric acid solutions. While their coordination with U(VI) has been extensively studied, their behavior toward tetravalent actinides under conditions relevant to spent nuclear fuel reprocessing remains poorly understood. Here, we investigated the extraction and coordination chemistry of Th(IV) in the presence of excess U(VI). Using a combination of solvent extraction, UV-Vis and Raman, we demonstrated that when the organic phase is pre-loaded with the uranyl ion pair [UO2L(NO3)]+[UO2(NO3)3]-, Th(IV) undergoes a selective anion-exchange reaction with the trinitratouranyl anion, forming the mixed ion pair [UO2L(NO3)]+[Th(H2O)2(NO3)5]-. Single-crystal X-ray diffraction further confirms the formation of heterometallic U-Th complexes, including ([UO2L(NO3)]+)2[Th(NO3)6]2-, providing direct structural evidence for mixed-metal ion pairing. These results revealed a previously unrecognized mechanism of Th(IV) uptake driven by anion exchange rather than direct ligand coordination.

In this work, we introduce the novel possibility of producing blue fluorescent ultraviolet pigments from phosphogypsum. The obtained materials are characterized by X-ray diffraction (XRD), transmission electron microscopy, and X-ray photoelectron spectroscopy (XPS). The formation of the CaS phase in the sample during the reduction of calcium sulfate was established. Thermal treatment of phosphogypsum in the presence of a reducing agent (potato starch) under environmental isolation conditions is found to yield high-quality products with high added value. The highest luminosity is established in samples containing 0.6 mol. %, which were heat-treated under a temperature of 1100 °C for 60 min. The synthesized CaS:Cu materials are shown to emit light in the blue region of the spectrum, with an emission maximum at a wavelength of 480–490 nm. The developed technological methods open the possibility to recycle chemical industry waste, which contributes to the achievement of sustainable development goals, in particular, the goal of ensuring rational consumption and production patterns.

Lanthanide complexes are widely used in both luminescent thermometry and catalysis, yet their integration into a single material remains a major challenge. Herein, we report novel terbium and europium complexes with a bispidine-based ligand conjugated to benzoic acid via a triazole linker. These complexes exhibit dual functionality: they act as homogeneous catalysts for the Michael addition reaction and simultaneously serve as ratio-metric luminescent thermometers. The mixed-metal complex (Eu0.1Tb0.9)(L)(TFA)2 center dot H2O demonstrates bright emission with quantum yields up to 56 %, and europium lifetime-based thermometry shows a relative sensitivity of 1.7 %/ degrees C with a temperature uncertainty below 0.5 degrees C. Notably, the catalytic activity arises only in the metalligand complex form, as neither the ligand nor lanthanide salts alone promote the reaction. To the best of our knowledge, this is the first report of a rare-earth complex combining homogeneous catalysis with luminescent thermometry in solution.

Luminescent thermometry in the near-infrared (NIR) range remains a critical challenge for both high-temperature environments and live-cell applications. While reproducibility remains a crucial challenge, particularly for high-temperature applications. Here we report a series of lanthanide pyrenates (Yb,Nd)(pyr)3 that demonstrate unprecedented reproducibility during thermal cycling up to 300 °C, with ratiometric temperature sensitivities reaching 8% K-1. The complexes form stable nanoparticles exhibiting high emission intensities, low cytotoxicity, and temperature sensitivity (1.5% K-1) in the physiological range.

Lanthanide-based emitters are attracting increasing interest for their potential in high-performance OLEDs due to their narrow emission bands, high photostability, and functional versatility. At the same time, their intrinsically low radiative rates, long excited-state lifetimes and poor charge-transport properties continue to limit device performance. In parallel, modern OLED technology has been driven primarily by charge-transfer phosphorescent and thermally activated delayed fluorescence (TADF) emitters, which can already deliver narrow emission and high efficiencies across the visible and part of the NIR spectrum. Against this background, the genuinely untapped potential of lanthanide emitters lies not simply in spectral purity, but in their ability to combine multifunctionality (dual emission Eu3+–Yb3+, optical thermometry, circularly polarized luminescence) with advanced photonic and plasmonic architectures under electrical excitation. These materials enable simultaneous optical thermometry and electroluminescence, with LIR values showing excellent agreement with external thermocouple measurements over a broad temperature range. OLED devices incorporating these complexes demonstrate stable operation, and their luminescence properties are further enhanced by integration with engineered plasmonic metasurfaces. This integration leads to a significant increase in emission directionality and a reduction of the excited-state lifetime via Purcell enhancement, without compromising spectral integrity. Our findings highlight the promise of lanthanide-based coordination compounds as multifunctional emitters for next-generation optoelectronic devices and suggest new pathways toward intelligent OLED architectures with integrated sensing and directional control.

Luminescent thermometry in the near-infrared (NIR) range remains a critical challenge for both high-temperature environments and live-cell applications. While reproducibility remains a crucial challenge, particularly for high-temperature applications. Here we report a series of lanthanide pyrenates (Yb,Nd)(pyr)(3) that demonstrate unprecedented reproducibility during thermal cycling up to 300 degrees C, with ratiometric temperature sensitivities reaching 8% K-1. The complexes form stable nanoparticles exhibiting high emission intensities, low cytotoxicity, and temperature sensitivity (1.5% K-1) in the physiological range

Eu-based emitters are known to offer narrow-band red luminescence, making them ideal for use as OLEDs. However, their long excited-state lifetime limits device efficiency compared to other materials. This paper aims to demonstrate that the integrating plasmonic resonances can reduce the lifetime and enable the directional emission outcoupling of various kinds of luminescent materials. Here, we employ one-dimensional aluminum plasmonic crystals (PCs) to control the directionality of photoluminescence in Eu(dbm)3(TDZP) (dbm = dibenzoylmethanate, TDZP = thiadiazolophenanthroline). The PCs with tailored periodicity were fabricated to achieve spectral overlap between surface plasmon resonances and the electric dipole transition of europium at 612 nm. Tuning periodicity directed the emission to near ±7° with a narrow angular divergence of 5°. At the resonance, the 4-fold enhancement in photoluminescence intensity was observed. Coupling the emission with surface plasmons and outcoupling it to the far-field decreased the lifetime of Eu(dbm)3(TDZP) by 1.7 times. This study therefore demonstrates the potential of plasmonic engineering to overcome the limitations of lanthanide emitters.

Dysprosium-doped calcium-strontium vanadate(V) hydroxyapatites (Ca1-ySry)10(VO4)6(OH)2:Dy, y = 0-0.4, were synthesized by the solid-state reaction at temperatures between 900 and 1000 °C. Dy3+ substitutes for Ca2+ at the 6h Wyckoff site (Ca2) and displaces strongly toward the isolated oxygen anion imbedded in the trigonal channel. This results in the formation of dysprosyl ion DyO+ with a short bond length of 2.15 Å. In zero external magnetic field and below 65 K, the compounds exhibit slow relaxation of the magnetization. With increasing strontium content y, the energy barrier for remagnetization grows from 614 cm-1 to 699 cm-1, the magnetization blocking temperature changes from 3 to 5.5 K, and the magnetization hysteresis at T = 2 K extends from 12 to 16 kOe. The photoluminescence bands exhibit a large crystal field splitting that increases with y. The electronic energy level diagram of Dy3+ obtained from the luminescence data agrees well with the measured magnetic properties. That is the first example of the DyO+ single-ion magnet (SIM) in a nonphosphate compound. This provides an opportunity for comparative studies to reveal new relations between crystal structure details and SIM parameters.

In this study, we report the synthesis peculiarities of lanthanide pyrenates, which reveal an unprecedented dehydration process in water: Yb(pyr)3(H2O)5 → Yb(pyr)3(H2O)1.5 → Yb(pyr)3. Ln(pyr)3 are isostructural in the row of Ln = Ce-Yb, and for highly crystalline Ho(pyr)3, the crystal structure was obtained by Rietveld refinement. The morphology evolution upon boiling was studied for ytterbium pyrenates, and the morphology was demonstrated to correlate with luminosity. We proposed the mechanism explaining this dependence and confirmed it through time-resolved photoluminescence studies. As a result of the morphology optimization, the quantum yield increased four times, and the highest to date quantum yield of a solid ytterbium complex was obtained (6.1% in Yb0.6Gd0.4(pyr)3).

Organic light-emitting diodes (OLEDs) with dual emission in the red and near-infrared regions offer a breakthrough opportunity for simplifying pulse oximetry technology. Here, a new class of bimetallic complexes Eu0.1Yb0.9(L)3Q (L = β-diketonates; Q = neutral ligands) with simultaneous emission at 612 and 978 nm has been reported, optimized for solution-processed OLEDs. A device based on Eu0.1Yb0.9(dbm)3thiadiazolophenanthroline (TDZP) exhibits the highest electroluminescence intensity in both spectral ranges and is employed as a single-pixel light source in a custom-built pulse oximeter prototype. The prototype demonstrates real-time measurement of heart rate and blood oxygen saturation in full agreement with commercial devices. This is the first demonstration of a fully functional OLED-based oximeter relying on dual-emissive lanthanide complexes. This results pave the way for next-generation wearable biomedical sensors using advanced emissive materials and simplified device architectures.

Europium‐based coordination compounds possessing narrow luminescence bands are promising emissive materials for organic light‐emitting devices with high colour purity in the red spectral region. However, OLEDs with organic emissive layers based on lanthanides generally suffer from a slow recombination time (≈1 ms), which leads to a relatively low external quantum efficiency. Here, gold nanorods are employed with optimized resonant optical properties for the wavelength range 500–700 nm to modify photo‐ and electroluminescence from the Eu‐based emission layer. Three different emissive europium complexes with a photoluminescence quantum yield of up to 100 % in powder and up to 63% in thin film are used. The experimental results supported by theoretical simulations show that the introduction of gold nanorods in the emission layer results in a 54% increase in the OLED performance. Thus, the highest brightness of solution‐processed Eu‐based OLEDs is obtained using the Eu(dbm) 3 TDZP complex with incorporated gold nanorods.

Lanthanide-based coordination complexes represent a promising class of materials for cathodoluminescence (CL) applications, offering sharp emission profiles and spectral tunability. However, their practical use has been limited by poor stability under electron-beam irradiation, particularly in organic systems. In this work, we investigate the cathodoluminescence degradation behavior of a model europium coordination compound Eu2(tph)3(Phen)2(H2O)2 (tph = terephthalate, Phen = ophenanthroline) under electron-beam excitation through time-resolved measurements, Raman spectroscopy, and structural analysis. The CL emission exhibits a two-stage decay regime: a rapid initial drop attributed to radiolytic degradation, followed by a slower exponential decay consistent with thermal decomposition. Mechanistic assignments were validated by systematically varying film thickness, incorporating a high-kappa polysiloxane thermal paste, and comparing CL behavior at different accelerating voltages (3 kV and 7 kV). Enhanced heat dissipation effectively suppressed thermal degradation, extending the operational voltage window and mitigating carbonization, as confirmed by post-irradiation optical and spectroscopic analyses. Notably, this study reports the slowest degradation rate yet observed for lanthanide-based cathodoluminophores, clarifies the dual nature of CL degradation in hybrid systems and highlights the importance of radiolysis suppression for future device development.

A dual-emissive ytterbium complex with a pyrene-substituted Schiff base ligand was synthesized and characterized. The complex exhibits both visible and near-infrared (NIR) emissions, with the emission bands ratio showing a significant temperature dependence in the range of 77-420 K. This feature makes the complex suitable for luminescent thermometry applications including inside of the organic light-emitting diode (OLEDs) emission layer (EML). Several heterostructures with different hole transport layers and different thicknesses of the EML were tested. The OLED1 with thinner EML demonstrate external current efficiency (ECE) up to 30 mu W/W while electroluminescence spectra contain both vis and NIR emission bands that make it possible to measure EML temperature which reach up to 77-114 degrees C.

A series of microcrystalline NaYF4 nanoparticles doped with Yb and Er were synthesized, and their Stokes and anti-Stokes emission was studied. Its temperature dependence made it possible to obtain high-temperature luminescent thermometry materials. The prospects of both Stokes and anti-Stokes luminescence for luminescent thermometry were studied and discussed.

The cathodoluminescence (CL) of terbium coordination compounds is studied in order to establish its correlation to photoluminescence (PL), as well as to increase its intensity and stability over time. A special setup was designed for this purpose. It is found that terbium complexes anionic carboxylate ligands, as well as NO3, and neutral ligands of different nature display luminescence of various intensities under excitation by fast electrons. Their spectra contain only characteristic narrow bands of terbium f–f transitions. Terbium terephthalate shows the highest CL intensity, as well as high stability over time.

A novel method has been developed for fabricating cholesteric liquid crystal polymer composite containing a luminescent europium complex. It involves creating porous cholesteric polymer networks, introducing the europium complex into the pores and encapsulating it through the UV-induced polymerisation of a nematic diacrylate. The resulting composite exhibits bright red luminescence upon excitation by UV light which is strongly circularly polarised. Such materials have potential applications in display technologies, counterfeit protection and other fields.