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Electron transfer between heterogeneous lanthanides in BaF2 crystals
摘要： Forward electron photo-transfer and reverse thermal transfer between divalent and trivalent heterogeneous lanthanides in barium fluoride crystals has been studied using optical absorption. In crystals activated by two heterogeneous lanthanides and grown in reducing conditions, one of the lanthanides becomes bivalent whereas the other lanthanide remains trivalent. Illumination of the crystal in the ultraviolet bands led to the transfer of electrons from divalent lanthalides (Eu, Yb, Sm) to trivalent ions (Ho, Nd, Dy, Tm, Sm, Yb). The thermal ionization energies to the conduction band of created lanthanides are determined from the thermal bleaching curves of absorption bands. The experimental energies are compared with the estimated energies of the Dorenbos model.
关键词： BaF2,level positions,electron phototransfer,urbach constant,lanthanide,absorption,spectroscopy
更新于2025-09-19 17:15:36
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Eu3+ as a luminescence probe in DNA studies: Structural and conformational implications
摘要： Lanthanide ions are widely used as luminescent probes for structural studies of various biomolecules, including DNA. Latest developments of circularly polarized luminescence (CPL) methodology further boosted interest to luminescence techniques. However, an effect of the lanthanide probes themselves on the DNA structure and conformation was investigated only partially and not for all lanthanides. In the present work, we performed a detailed spectroscopic study of Eu3+ complexes with native double-stranded DNA and compared them to the relevant complexes with single-stranded DNA. We employed infrared (IR), vibrational circular dichroism (VCD) and electronic circular dichroism (ECD) spectroscopic methods to investigate Eu3+ effect on DNA structure and conformational transitions. It was shown that Eu3+ ions can induce significant alteration of the native DNA structure at the concentrations often used in luminescence studies. While no DNA denaturation was observed at these metal ion concentrations, significant unstacking of the base pairs and disordering of the sugar-phosphate backbone, partial appearance of the A-form backbone geometry, and DNA transition into condensed ψ–type form took place. Eu3+ binding to single-stranded DNA was more pronounced than the binding to double-stranded DNA. We detected the main Eu3+ binding sites and determined the metal ion concentration range in which DNA geometry remains largely unaltered. The results obtained in the current study could be used for tuning the luminescence and CPL structural studies of DNA utilizing Eu3+ ions as probes.
关键词： infrared (IR),DNA condensation,lanthanide ions,DNA structure,luminescence probe,vibrational circular dichroism (VCD)
更新于2025-09-19 17:15:36
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EXPRESS: Fluorescence Turn-On Detection of Ascorbic Acid Using a Self-Assembled Lanthanide Polymer Nanoparticle
摘要： Ascorbic acid (AA), or vitamin C, is an important reactive biological molecule in vivo, and the abnormal level AA is associated with many diseases. Therefore, the rapid, sensitive, and selective detection of AA levels is of significance in cases of medical assay and diagnosis. Compared with other nanoparticles, lanthanide coordination polymer nanoparticles (Ln-CPs) have been demonstrated as the excellent biomolecule sensing platforms due to their unique optical properties and intrinsic porosities. In this work, the cerium coordination polymer nanoparticles ATP-Ce-Tris were synthesized in a simple and quick way. The synthesized ATP-Ce-Tris nanoparticle shows the characteristic peak of Ce3+ located at 365 nm, which is corresponding to the 4f→5d transition of Ce3+. In the presence of Fe3+, the fluorescence of ATP-Ce-Tris quenched, and the following added ascorbic acid (AA) makes it restoring effectively. Based on this, we constructed a fluorescence probe with excellent sensitivity for AA sensing in a wide linear relationship from 0.05 to 500 μM. The detection limit was as low as 18 nM (signal-to-noise ratio of three), which is one or two orders of magnitude lower than those of reported sensors. The proposed sensing systems also exhibits excellent sensitivity for AA detection in human serum sample, exploiting a valuable platform for AA analysis in clinic diagnostic and drug screening.
关键词： Lanthanide coordination polymer,ascorbic acid,fluorescence,turn-on
更新于2025-09-19 17:13:59
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Influence of nonradiative Auger process in the lanthanide complexes lifetime near interfaces in organic light-emitting diode structures
摘要： The low efficiency of organic light-emitting diodes based on lanthanide complexes is generally attributed to the triplet-triplet annihilation processes in the regime of high concentration of excited states caused by their long lifetimes and optical losses near the interfaces of multilayer device structures. Despite the enormous effort to synthesize short-lived complexes and minimize the optical losses in the interfaces, it remains insufficient in understanding the exciton recombination processes that reduce the lifetime of these complexes. Herein, we investigated the influence of the exciton recombination processes on a Tb complex (Tb-C) lifetime in the regime of a highly excited state concentration as a function of the distance between the carrier layer and the interface by using a typical organic light-emitting diode structure. Our results show that a 10 nm-thick Alq3 layer decreases the exciton lifetime of the Tb-C, increasing approximately by 16 times the spontaneous emission decay rate of triplet exciton. The effects of interference and optical losses at the metallic interface contribute actively to the modulation of the emission intensity and lifetime decay. However, these effects alone do not explain the significant increase in the emission decay rate. The nonradiative Auger process at the Alq3/Tb-C interface seems to be largely accountable for the Tb-C lifetime reduction as the energy released by the terbium ion occurs by the excitation of an adjacent electron at higher energy. Furthermore, we propose a simple theoretical model to explain the observed effects. These results can provide a new approach to reduce the lanthanide complexes’ lifetime through the Auger electron process near the interface and thus improve the performance of organic light-emitting diodes.
关键词： exciton recombination,Auger process,organic light-emitting diodes,lifetime reduction,lanthanide complexes
更新于2025-09-19 17:13:59
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Light-controlled efficient photoluminescence based on an europium β-diketonate complex with single-crystal-to-single-crystal [2+2] cycloaddition
摘要： A brand new europium(III) b-diketonate complex undergoes a single-crystal-to-single-crystal transformation via [2+2] cycloaddition after UV irradiation, triggering strong Eu(III) red emission turn-on, which is highly photostable even after 50 hours of irradiation. A photo-patterning process is successfully conducted for security printing application in materials science.
关键词： lanthanide complexes,single-crystal-to-single-crystal transformation,security printing,UV irradiation,photoluminescent
更新于2025-09-16 10:30:52
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Self-assembled monolayers of polyoxovanadates with phthalocyaninato lanthanide moieties on gold surfaces
摘要： The two first representatives of phthalocyaninato (Pc) lanthanide-ligated polyoxovanadate cages {[V12O32(Cl)](LnPc)n}n(cid:2)5 (n = 1 or 2, Ln = Yb3+) were synthesised and fully characterised. These magnetic complexes form two-dimensional self-assembled monolayers exhibiting electrical conductivity on gold substrate surfaces, as assessed by using an EGaIn tip.
关键词： gold surfaces,electrical conductivity,phthalocyaninato lanthanide,polyoxovanadates,self-assembled monolayers
更新于2025-09-16 10:30:52
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On the development of a new approach to the design of lanthanide-based materials for solution-processed OLEDs
摘要： The targeted design of lanthanide-based emitters for solution-processed organic light-emitting diodes (OLEDs) resulted in obtaining an NIR OLED with one of the highest efficiencies among ytterbium-based solution-processed OLEDs (30 μW W?1). The design was aimed at the combination of high luminescence efficiency with solubility and charge carrier mobility. The latter was achieved thanks to the introduction of the purposefully selected neutral ligands, which combine electron mobility and the ability to sensitize lanthanide luminescence. Besides, the HOMO and LUMO energies and charge carrier mobility of solution-processed thin films of coordination compounds were measured experimentally for the first time, and novel highly luminescent europium-based materials with PLQYs of up to 80% and purely NIR luminescent ytterbium complexes were obtained.
关键词： NIR OLED,europium complexes,lanthanide-based materials,solution-processed OLEDs,ytterbium complexes
更新于2025-09-16 10:30:52
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Rationally assembled nonanuclear lanthanide clusters: Dy <sub/>9</sub> displays slow relaxation of magnetization and Tb <sub/>9</sub> serves as luminescent sensor for Fe <sup>3+</sup> , CrO <sub/>4</sub><sup>2?</sup> and Cr <sub/>2</sub> O <sub/>7</sub><sup>2?</sup>
摘要： The utilization of a Schi? base ligand 2-((2-hydroxy-4-methoxy-benzylideneamino)methyl)phenol (H2L) a?orded five nonanuclear lanthanide(III) clusters of formula [Ln9L8(m3-OH)8(m5-O)2(DMF)8][H3O](cid:3)nH2O (Ln = Eu, n = 1 (1[H3O](cid:3)H2O); Ln = Gd, n = 4 (2[H3O](cid:3)4H2O); Ln = Tb, n = 3 (3[H3O](cid:3)3H2O); Ln = Dy, n = 6 (4[H3O](cid:3)6H2O); Ln = Ho, n = 2 (5[H3O](cid:3)2H2O)). Single-crystal X-ray di?raction analysis revealed that all of the complexes were isomorphous and had a diabolo-like topology. The intriguing Ln9 core was constructed by two square pyramidal units that shared a vertex metal centre. Variable-temperature dc magnetic susceptibility studies indicated weak antiferromagnetic interactions for 2[H3O](cid:3)4H2O, 3[H3O](cid:3)3H2O, 4[H3O](cid:3)6H2O and 5[H3O](cid:3)2H2O. The DyIII 9 cluster displayed a slow relaxation of magnetization. Fluorescence measurements revealed an intense green photoluminescence for the TbIII 9 compound. The luminescence tests showed that the TbIII 9 analogue could perform as a highly sensitive, selective and recyclable luminescence sensing material for Fe3+, CrO4 2(cid:2). In this work, the H2L ligand was derived by finely modifying the previously designed compounds (((2-hydroxy-3-methoxybenzyl)imino)- 2(cid:2) and Cr2O7 2(cid:2)? *a and methyl)-6-ethoxyphenol and (((2-hydroxy-3-methoxybenzyl)imino)methyl)-6-methoxyphenol, from which the Ln2 and Ln4 clusters were successfully prepared and reported. Noticeably, the decisive decrease in the steric hindrance of the predesigned ligands resulted in the expansion of the nuclearity. This work demonstrated the synthetic potential for assembling the large clusters by rationally decreasing the steric rsc.li/njc hindrance of the analogous ligands.
关键词： magnetization,Fe3+,CrO4 2(cid:2),luminescent sensor,Cr2O7 2(cid:2),lanthanide clusters
更新于2025-09-16 10:30:52
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Full-color persistent luminescence tuning: A marriage of perovskite quantum dots and lanthanide ions
摘要： In modern society, luminescent materials capable of emitting various colored lights are critically important for lighting and display systems. As a typical kind of luminescent materials, the persistent luminescence phosphors have been widely investigated as night-light vision materials due to their many significant applications such as emergency route signage and security signals, bio-labels, photocatalysts, anti-counterfeiting, optical sensors, and optical data storage. However, realizing multicolored persistent luminescence phosphors has been a long-standing challenge, thus posing a serious problem in their practical applications. In a recent publication in Angewandte Chemie International Edition, Prof. Xueyuan Chen and co-workers demonstrated a simple but effective approach to fine-tuning the persistent luminescence colors, based upon the composites of lanthanide ions doped CaAl2O4:Eu2+,Nd3+ (CAO) blue persistent phosphors with all-inorganic CsPbX3 (X = Cl, Br, and I) perovskite quantum dots (PeQDs). With the help of the radiative energy transfer from CAO blue persistent phosphors to CsPbX3 PeQDs, the persistent luminescence colors can be precisely controlled through tailoring of the PeQDs bandgap. The approach allowed access to full-spectrum persistent luminescence with wavelengths covering the entire visible spectral range by single-wavelength excitation, thus offering new opportunities for persistent luminescence materials in many important emerging applications.
关键词： persistent luminescence,lanthanide ions,full-color tuning,perovskite quantum dots
更新于2025-09-16 10:30:52
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Near-infrared Laser Triggered Full-Color Tuning Photon Upconversion and Intense White Emission in Single Gd2O3 Microparticle
摘要： Full-color emission fluorescence materials are of imperious demands in information storage, graphics imaging and anti-counterfeiting fields. However, it is still a formidable challenge to develop a single material with full-color emission and high purity white output under a NIR-light excitation. Herein, we design a novel and convenient strategy to tune the upconversion luminescence color with full color range in lanthanide ions doped Gd2O3 microspheres via a single NIR laser sensitization. Different from the typical ion-dependent tuning of color, the bright and flexible full-color emission tuning from blue to cyan, green, yellow, pink, and red can be controllable implementation in a single microparticle. Particularity, benefiting from the laser sensitive color adjustment, highly intense white color emission can be simultaneously achieved in diverse doped ion concentration particles. In addition, the upconversion emission intensity has been evidently improved if using a NIR laser sensitization, leading to significantly enhanced upconversion red luminescence signal (44-fold) at the power 446 mW. The mechanistic investigations and dynamics analysis reveal that the unprecedented color tunability from these microcrystals is attributed to dynamic control of multi-energy transfer and multi-cross relaxation process. Furthermore, owning to their excellent upconversion luminescence properties, Gd2O3 microparticles could be used to the anticounterfeiting application in different colors. These findings not only open a way to fabricate a single material to fine tuning upconversion emission in a full color gamut, but also give the possibility to construction of the multicolor imaging for anti-counterfeiting applications.
关键词： upconversion luminescence,anti-counterfeiting,full color emission,lanthanide ions doped Gd2O3 microspheres,white color emission,laser sensitization
更新于2025-09-16 10:30:52