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Within the field of magnetism, magnetic frustration is a generous source of new phases of matter with unusual and exciting physical properties. Magnetic order is dictated by the interdependence of local electronic states and their real-space interactions decorating materials lattices. These local states can compete or work together to drive differing magnetic states of matter, ranging from the typical collinear (anti)ferromagnets to more exotic, highly-entangled ground states with emergent phenomena in small spin systems (S = 1/2). These correlated phases are predicted to arise in materials lattices that incite multiple equivalent interactions without a readily apparent magnetic ground state configuration in so called magnetic frustration. In turn, this frustration can lead to massively degenerate classical ground states hinting that instead a novel entangled phase could arise from the competition. Even with decades of research in this field, frustrated magnets remain an exciting and growing field of research as new magnetic phases arediscovered. Herein, the physical properties of insulating lanthanide-based frustrated magnets areexplored from select members of the ALnX2 (A = alkali, Ln = lanthanide, X = chalcogenide) family of materials. This materials family crystallizes in various structures dictated by the ratio of the lanthanide radius to the alkali and chalcogenide radii, and this thesis focuses on two frustrated crystal lattices in this family, the equilateral triangular lattice and the elongated diamond lattice. We find that triangular lattice NaYbO2 does not conventionally order to 50 mK and instead contains an unconventional quantum disordered ground state that is tunable in an external magnetic field. However, structurally-similar triangular lattice KCeO2 magnetically orders below 300 mK with a small magnetic moment. Additionally, we show how the Heisenberg J1 - J2 model can be applied to the elongated magnetic diamond lattice in LiYbO2 and NaCeO2 where collinear or spiral magnetic order arises depending on the ratio of J2/J1. In LiYbO2, spiral magnetic order undergoes an incommensurate-to-commensurate structure under an external field below 1 K while NaCeO2 exhibits long range collinear antiferromagnetic order below 3.2 K. Overall, these materials studies advance the dependence of frustrated magnetic phases on external parameters, lanthanide character, and lattice geometry.

Lanthanide doped fluorescence nanoparticles have gained considerable attention in biomedical applications. However, the low uptake efficiency of nanoparticles by cells has limited their applications. In this work, we demonstrate how the uptake efficiency is affected by the size of nanoparticles under flow conditions. Using the same size NaYF4:20% Yb3+,2% Er3+,2% Ce3+ nanoparticles as core, NaYF4:20% Yb3+,2% Er3+,2% Ce3+@NaYF4 core-shell structured nanorods with different sizes of 60–220 nm were synthesized by thermal decomposition and hot injection method. Under excitation at 980 nm, a strong upconversion green emission (541 nm, 2H11/2 → 4I15/2 of Er3+) is observed for all samples. The emission intensity for each size nanorod was calibrated and is found to depend on the width of NRs. Under flow conditions, the nanorods with 96 nm show a maximum uptake efficiency by endothelial cells. This work demonstrates the importance of optimizing the size for improving the uptake efficiency of lanthanide-doped nanoparticles.

It remained challenging to fabricate Tb3+-doped lanthanide nanocrystals (NCs) to simultaneously acquire strong energy migration upconversion (EMU) emissions of Tb3+ while suppressing the Tm3+ UV up...

This work focuses on lanthanide-based inorganic-organic structures. The properties of lanthanide-based metal organic frameworks (Ln-MOFs) and layered rare earth hydroxides (LREHs) are reviewed and compared. Three distinct projects are presented herein: 1) the solvothermal syntheses of a series of Ln-MOFs with the ligand biphenyl-4,4-dicarboxylate (BPDC), 2) the solvothermal syntheses of a series of Ln-MOFs with the ligand 2,6-naphthalenedicarboxylate (NDC), and 3) the hydrothermal syntheses of a series of neodymium-based LREHs with increasing α,ω-alkanedisulfonate (ADS) carbon chain lengths.The first project, which we refer to as Ln-BPDC (structures SLUG-43–48), is an isomorphous series of six anionic frameworks with the general structure [Ln(BPDC)2–][NH2(CH3)2+] (Ln = La, Ce, Nd, Eu, Gd, Er). The Ln(III) metal centers exhibit eight-coordinate binding to six different BPDC2- ligands. The anionic framework is charge-balanced by a dimethylammonium cation. The materials all possess the same 3-D structure and crystallize in the orthorhombic space group Pbcn. All exhibit thermal stability up to 300 °C and decompose to Ln2O3 after 800 °C. The Eu-BPDC structure exhibits strong fluorescence in the 612-620 nm range and a quantum yield of 2.11%. The second project, we refer to as Ln-NDC (structures SLUG-49–52). This project consists of four neutrally charged structures that each crystallize in distinct space groups. Their formulas are [La6(NDC)9(DMF)3•6 DMF], [Nd2(NDC)3(DMF)2], [Eu2(NDC)3(DMF)2•DMF], and [Gd4(NDC)6(DMF)4]. The Ln(III) centers exhibit different coordination numbers (ranging from seven to nine), the NDC ligand exhibits multiple binding modes, and DMF solvent molecules are found either coordinated or floating within the structures. Despite these differences, the NDC-based structures exhibit similar thermal decomposition profiles and infrared spectra. The Eu-NDC structure exhibits a sharp red-orange luminescence at 613 nm and a quantum yield of 3.56%. Lastly, the Nd-ADS project (structures SLUG-28–30) consists of three LREHs made of [Nd2(OH)4(OH2)22+] layers with interlamellar α,ω-[–O3S(CH2)nSO3–] anions (n = 2 to 4). These LREHs show an increase in thermal stability with increasing alkanedisulfonate chain length. As an initial example of anion exchange, all three materials show exchange for adipate, –O2C(CH2)4CO2–. Several insights on the structural differences between Ln-MOFs and LREHs are proposed. In comparing the mentioned projects, we suggest the differences between the isomorphous Ln-BPDC series and the diversity of structures in the Ln-NDC series are due to the rigidity of the NDC ligand and the synthesis temperatures. The dimensionality of lanthanide-based materials (3-D or 2-D) are affected by reaction pH. This work expands the chemistry of lanthanide MOFs and LREHs.

Energy transfer as an important component in light-harvesting antenna systems can mimic effectively natural photosynthesis processes, showing great potential in optoelectronic devices. Herein, we report a responsive polymeric hydrogel based on the combination of excited state intramolecular proton transfer (ESIPT) molecule (Salicylic acid, Sal) and terbium (III) (Tb3+), as enabled by external stimuli to construct artificial light-harvesting antenna systems. Benefiting from unique photophysical properties of Sal, the synthesized hydrogel displays a temperature-dependent reversible opaque ↔ transparent states transition, accompanied with an interesting photoluminescence behavior. Moreover, by further incorporating europium (III) (Eu3+) into the hydrogel, we demonstrate well-defined cascades of energy transfer that provides a tunable optical output from the collection of lanthanides by the excitation of a common sensitizer (Sal) upon base vapor stimulation. Efficient energy transfer efficiency from Tb3+ to Eu3+, as high as 97.8%, was also obtained as established by the time-resolved fluorescence spectroscopy analysis.

Luminescent metal–organic frameworks (MOFs) are of interest for sensing, theranostics, dosimetry, and other applications. The use of lanthanoids in MOF metal nodes allows for intrinsic met-al-based luminescence. In this work, a facile route for modulat-ing the photoluminescent and radioluminescent properties of Tb(III)-based MOFs is reported. By using Tb(III)-cluster nodes as X-ray attenuators, and organic linkers with varying excited state energies as sensitizers, MOFs with metal-based, linker-based, and metal+linker-based photo- and radioluminescence are reported.

Water-caused luminescence quenching is a well-known and intractable issue for luminescence lanthanide complexes, greatly confining their broad application as sensing and displaying devices in water system. Herein, an anionic and coordination-saturated lanthanide complex with a nanosheet-like structure has been prepared. It exhibits excellent photophysical properties both in solid state and in aqueous suspension. Noteworthily, a 13% improvement for sensitization efficiency from organic ligand to central lanthanide ion has been realized, indicating an exceptional phenomenon of water-induced luminescence improvement which is rarely reported previously. Moreover, the aqueous suspension of as-prepared luminophore could act as a chemo-sensor responding to various organic solvents in water. Both of water-induced luminescence improvement and extended sensing behavior in this work provide a new platform for developing highly performant and practical luminescent materials in the water system.

The water gas shift reaction is of vital significance for the generation and transition of energy due to the application in hydrogen production and industries such as ammonia synthesis and fuel cells. The influence of support doping and bimetallic alloying on the catalytic performance of Pt/CeO2-based nanocatalysts in water gas shift reaction was reported in this work. Various lanthanide ions and 3d transition metals were respectively introduced into the CeO2 support or Pt to form Pt/CeO2:Ln (Ln = La, Nd, Gd, Tb, Yb) and PtM/CeO2 (M = Fe, Co, Ni) nanocatalysts. The sample of Pt/CeO2:Tb showed the highest activity (TOF at 200 °C = 0.051 s-1) among the Pt/CeO2:Ln and the undoped Pt/CeO2 catalysts. Besides, the sample of PtFe/CeO2 exhibited the highest activity (TOF at 200 °C = 0.12 s-1) among PtM/CeO2 catalysts. The results of the multiple characterizations indicated that the catalytic activity of Pt/CeO2:Ln catalysts was closely correlated with the amount of oxygen vacancies in doped ceria support. However, the different activity of PtM/CeO2 bimetallic catalysts was owing to the various Pt oxidation states of the bimetals dispersed on ceria. The study of the reaction pathway indicated that both the samples of Pt/CeO2 and Pt/CeO2:Tb catalyzed the reaction through the formate pathway, and the enhanced activity of the latter derived from the increased concentration of oxygen vacancies along with promoted water dissociation. As for the sample of PtFe/CeO2, its catalytic mechanism was the carboxyl route with a higher reaction rate due to the moderate valence of Pt along with improved CO activation.

This work demonstrates that the introduction of positive lanthanide (Ln) and transition metal (TM) cations into polyoxotungstates (POTs) to stabilize negative oxoboron clusters is a feasible and ge...

Lanthanide ions doped luminescent materials are widely studied for latent fingerprint detection. However, most of these materials are synthesized at very high temperatures and use UV C light for visualization, which is harmful to eye, skin, etc. Herein, the Gd0.95Eu0.05PO4 nanorods synthesized by a simple co-precipitation method at 185 °C were reported for latent fingerprint visualization under 395 nm light. The Gd0.95Eu0.05PO4 nanomaterial has monoclinic crystal structure and shows rod-shaped morphology. Further, these Gd0.95Eu0.05PO4 nanorods exhibit excellent photoluminescence properties and strong fuchsia emission under UV light. These nanorods have been employed for developing latent fingerprints on various porous and non-porous substrates by the powder dusting technique, which exhibits clear and well defined details with high contrast, selectivity and sensitivity under 395 nm UV light. Latent fingerprints developed after 72 h of their deposition also show clear contrast with these nanorods. Therefore, the Gd0.95Eu0.05PO4 nanorods can be used for latent fingerprint visualization applications.

Summary Single-molecule magnets (SMMs) are molecules that can retain magnetic polarization in the absence of an external magnetic field and embody the ultimate size limit for spin-based information storage and processing. Multimetallic lanthanide complexes lacking magnetic exchange coupling enable fast relaxation pathways that attenuate the full potential of these species. Employment of diamagnetic heavy main group elements with diffuse orbitals may lead to unprecedented strong coupling. Herein, two bismuth-cluster-bridged lanthanide complexes, [K(THF)4]2[Cp∗2Ln2Bi6] (Cp∗ = pentamethylcyclopentadienyl; 1-Ln, Ln = Tb, Dy), were synthesized via a solution organometallic approach. The neutral [Ln2Bi6] heterometallocubane core features lanthanide centers that are bridged by a rare Bi66− Zintl ion, which supports strong ferromagnetic interactions between lanthanides. This affords the rare observation of magnetic blocking and open hysteresis loops for superexchange-coupled SMMs comprising solely lanthanide ions. Both compounds constitute the first SMMs containing bismuth donors paving the way for promising synthetic targets for quantum computation.

l -kynurenine (L-kyn) is a marker of prostate cancer. At present, the expensive instruments are usually applied to detect L-kyn in clinically, which limits its wide application for cancer diagnosis. Herein, three lanthanide metal–organic frameworks ([Ln(CHO2)3]n, Ln = Eu, Gd, and Tb) were designed and obtained, and detailly characterized by single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and luminescence spectroscopy. Further study reveals that [Tb(CHO2)3]n is a highly selective, ultra-sensitive, of strong anti-interference, highly stable, and non-expensive sensor for prostate cancer marker L-kyn. The limit of detection (LOD) for L-kyn sensing is a highly sensitive value of 1.0 × 10−9 mol/L. Furthermore, the sensing mechanism is discussed in detail.

Hybrids composed of biocompatible polymers reinforced with inorganic nanomaterials are useful for many biomedical applications including implantation and tissue regeneration and engineering. In thi...

Significant developments have been made in the past few decades in lanthanide (Ln) ions doped fluorosilicate glass-ceramics (Flusi-GCs). As a novel generation of luminescence materials with a wide range of applications, Flusi-GCs as a single host combine the advantages of glass and ceramics/crystals as well as fluorides and silicates. In this review, the chemical design principles and experimental procedures of Flusi-GCs are summarized in detail. Flusi-GCs are categorized as those containing heavy metal fluoride PbxCd1–xF2, rare earth (RE) fluoride RF3 (R = Y, La, Gd), alkaline earth fluoride MF2 (M = Ca, Sr, Ba), fluoride xMF2–yRF3 (R = Y, La–Lu), mAF-nRF3 (A = Li, Na, K), KTF3 (T = Zn, Mn) and K2SiF6 nanocrystals (NCs). Theoretical breakthroughs mainly by molecular dynamic (MD) simulation have been recapitulated as efficient routes for composition-design, nano-crystallization-prediction, and performance-optimization of Flusi-GCs containing target fluoride NCs. Essential research progresses pertaining photonic applications have been made in random lasers, communication amplifiers, optical fibers, and spectral converters, white light-emitting-diodes (WLEDs), and thermal sensors. In the end, we propose three prospective future research directions for Flusi-GCs.

The synthesis of a novel polyhedral oligomeric silsesquioxane functionalized with eight rigid and directional terpyridine-based arms (Ter-POSS) was successfully achieved via a Sonogashira reaction. The POSS based ligand was extensively characterized using different techniques including 1H, 13C and 29Si NMR as well as UV-Vis and fluorescence spectroscopies. The assembly of these nano-caged units in the presence of different transition metal ions (Fe2+, Zn2+ and Cu2+) as well as of a cation from the lanthanides (Eu3+) was investigated using absorption and emission spectroscopies. The final materials display an evident emission in different regions of the visible spectrum as a function of the cation employed. Additional insights into the structural organization of Ter-POSS in the presence of metal cations were obtained via molecular mechanics and molecular dynamics simulations. The polymeric material resulting from the complexation with europium displays a white light emission ascribed to the presence of combined contributions from the blue, green and red regions. The final self-assembled organizations display an increased quantum yield with the highest value (29.6%) obtained in the presence of Zn2+. Moreover, the white-light emitting europium-based nanostructure exhibits one of the highest quantum yields reported in the literature for similar solids.

Two unprecedented PIII–SbIII-heteroatom templated lanthanide-inserted heteropolyoxotungstates were obtained and their composite film was applied for the electrochemical immunosensing of auximone.

The application of nanomaterials made of rare earth elements within biomedical sciences continues to make significant progress. The rare earth elements, also called the lanthanides, play an essential role in modern life through materials and electronics. As we learn more about their utility, function, and underlying physics, we can contemplate extending their applications to biomedicine. This particularly applies to diagnosis and radiation therapy due to their relatively unique features, such as an ultra-wide Stokes shift in the luminescence, variable magnetism and potentially tunable properties, due to the library of lanthanides available and their multivalent oxidation state chemistry. The ability to prepare nanomaterials of relatively smaller sizes has increased the likelihood of use in vivo. In this review, we summarize the different emerging applications of nanoparticles with rare earth elements as the host or doped elements for biomedical applications in the past three to four years, especially in the area of imaging and disease diagnosis. Researchers have made progress in utilizing surfactants and polymers to modify the surface of lanthanide nanoparticles to enhance biocompatibility. At the same time, specific antibodies and proteins can also be conjugated to these nanoparticles to increase targeting efficiency for specific tumor models. Finally, in the near-infrared II imaging window, lanthanide nanoparticles have been shown to exhibit extraordinary bright emission, which is an exciting development for image-guided surgery.

The short-lived 146Sm-142Nd isotope system traces key early planetary differentiation processes that occurred during the first 500 million-years of solar system history. The variations of 142Nd/144Nd in terrestrial samples, typically within a range of ±20 ppm, are determined using high-precision mass spectrometry that requires quantitative separation of Nd from all other elements in the sample, including the neighboring lanthanides. Recent improvements in mass spectrometry have pushed the analytical precision of 142Nd/144Nd measurements down to ~2ppm. Non-mass-dependent isotope fractionation produced during the Nd separation, however, is a major factor limiting the quality of the 142Nd data. Popular chemical separation methods using Ln resins have unpredictable nuclear field shift effects that generate anomalous Nd isotope ratios. In order to solve this problem and potentially for resolving small 142Nd/144Nd variations within ±5 ppm, in this study, we present a new two-step column separation method that effectively removes the isobaric interferences of Ce, Pr and Sm, with a recovery rate of Nd greater than 98%. JNdi-1 standard solutions doped with these interfering elements, and geological reference materials are tested to document the performance of this method. A set of titanite samples from the Pilbara craton in western Australia was also investigated to test the potential isotope fractionation effects. The same samples were processed using our method and the widely used Ln method. In contrast to the nuclear field shift effects observed from the samples using the Ln method, the results based on our new method show no detectable isotope fractionation, which further confirms the reliability of this new column chemistry scheme that is optimized for ppm-level precision Nd isotope ratio measurement, especially for resolving small variations in 142Nd/144Nd caused by the decay of 146Sm.

Background: The rapid and increasing use of the nanomaterials in the development of electrochemiluminescence (ECL) sensors is a significant area of study for its massive potential in the practical application of nanosensor fabrication. Recently, nanomaterials (NMs) have been widely applied in vast majority of ECL studies to remarkably amplify signals owing to their excellent conductivity, large surface area and sometimes catalytic activity. Lanthanides, as f-block-based elements, possess remarkable chemical and physical properties. This review covers the use of lanthanide NMs, focusing on their use in ECL for signal amplification in sensing applications. Methods: We present the recent advances in ECL nanomaterials including lanthanides NMs with a particular emphasis on Ce, Sm, Eu and Yb. We introduce their properties along with applications in different ECL sensors. A major focus is placed upon numerous research strategies for addressing the signal amplification with lanthanide NMs in ECL. Results: Lanthanide NMs as the amplification element can provide an ideal ECL platform for enhancing the signal of a sensor due to their chemical and physical properties. Function of lanthanide NMs on signal amplification remarkably depend on their large surface area to load sufficient signal molecules, high conductivity to promote electron-transfer reaction. Conclusion: ECL as a powerful analytical technique has been widely used in various aspects. As the development of the nanotechnology and nanoscience, lanthanide nanomaterials have shown the remarkable advantages in analytical applications due to their significant physical and chemical properties. We predict that in the future, the demand for ECL sensors will be high due to their potential in a diverse range of applications. Also, we expect the research in nanomaterial-based sensors will still continue intensively and eventually become effectively routine analysis tools that could meet various challenges.

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.

Substantial lattice strain arising from lattice misfit of the components of core–shell nanomaterials used to accommodate lanthanide emitters usually significantly results in an inhomogeneous shell,...

Yb3+-doped phosphors have characteristic near-infrared (NIR) emissions, but their applications in phosphor-converted light-emitting-diodes (pc-LEDs) and Si solar cells are limited due to their mismatching excitation spectra. Here, we selected nitride La3Si6N11 (LSN) as host material to achieve Yb3+ NIR emission upon low-energy charge transfer (CT) excitation. The obtained phosphor LSN:Yb3+ has a broad CT excitation band ranging from 250 to 500 nm and narrowband NIR emissions ranging from 950 to 1100 nm centered at 983 nm. On the basis of spectral data, the vacuum referred binding energies (VRBE) schemes are constructed to locate energy levels of all lanthanide ions in LSN. We also fabricated NIR pc-LED device using 395 nm LED chip to demonstrate the potential applications of LSN:Yb3+ phosphors.

Photon upconversion of lanthanides has been a powerful means to convert low-energy photons into high-energy ones. However, in contrast to the mostly investigated lanthanide ions, it has remained a challenge for the efficient upconversion of Nd3+ due to the deleterious concentration quenching effect. Here we report an efficient strategy to enhance the upconversion of Nd3+ through the Yb3+-mediated energy cycling in a core-shell-shell nanostructure. Both Nd3+ and Yb3+ are confined in the interlayer, and the presence of Yb3+ in the Nd-sublattice provides a more matched energy for the upconversion transitions occurring at the intermediate state of Nd3+ towards much better population at its emissive levels. Moreover, this design also minimizes the possible cross-relaxation processes at both intermediate level and the emissive levels of Nd3+ which are the primary factors limiting the upconversion performance for the Nd3+-doped materials. Such energy cycling-enhanced upconversion shows promise in temperature sensing.

Research in the field of lanthanide-based luminescent hybrid silica materials has grown substantially in the last decades, given the unique spectroscopic properties of lanthanide(III) complexes and the stability and biocompatibility of silica hosts. The versatility of the sol-gel technique to produce glasses, fibers, films, nanoparticles and ceramics has turned it into one of the most powerful methods to achieve such goals. This review describes the most commonly used sol-gel strategies to insert a luminescent lanthanide(III) complex inside a silica host and their potential applications, with the aim to help in the choice for a particular functional material. In particular, the focus is set on the different approaches developed to embed the visible or near infrared emitting guest in the silica matrix, either by entrapment within the three-dimensional network, anchoring on the surface of a nano or microparticle or inclusion in a mesopore. In addition, the usual organic ligands and the different functionalization strategies are discussed.

Cluster-based functional materials have made remarkable progress owing to their wonderful structures and distinctive physicochemical performances, one of on-going advancements of which is basically driven by synthetic chemistry of exploring and constructing novel nanosized gigantic polyoxometalate (POM) aggregates. In this article, an unprecedented nanoscale hexameric arsenotungstate aggregate Na9K16H4[Er0.5K0.5(H2O)7][Er5W10O26(H2O)14][B-α-AsW9O33]6·102H2O (1) has been synthesized by the combined synthetic strategy of simultaneously using the arsenotungstate precursor and simple tungstate material in a highly acidic aqueous solution. The {[Er5W10O26(H2O)14][B-α-AsW9O33]6}31− polyanion in 1 consists of an intriguing dumbbell-shaped pentadeca-nuclear W-Er heterometal {Er5W10O26(H2O)14}23+ cluster connecting six trilacunary [B-α-AsW9O33]9− moieties, which has never been seen previously. Furthermore, through electropolymerization of 1 and pyrrole on the conductive substrate, a thickness-controllable and robust 1-PPY (PPY = polypyrrole) hybrid film was successfully prepared, which represents the first POM-PPY film assembled from high-nuclear lanthanide (Ln) encapsulated POM and PPY hitherto. The 1-PPY film-based electrochemical biosensor exhibits a favorable recognition performance for ochratoxin A in multiple media. This work not only provides a feasible combined synthetic strategy of the POM precursor and simple tungstate material for constructing complicated multi-Ln-inserted POM aggregates, but also offers a promising electrochemical platform constructed from POM-based conductive films for identifying trace biomolecules in complex environments.

Trivalent lanthanide ions (Ln3+) have electronically isolated f-orbitals that support excited states, which, due to their ultra-narrow emission and long spin coherence lifetimes, are potentially su...

Polarized emission, an inherent characteristic that correlated with structure and morphology, is very sensitive to orientation. For the upconversion (UC) emission of lanthanides, the mechanism of polarization is rarely discussed, and the highly polarized UC emissions are poorly developed. Herein, with the benefit of the strong anisotropic crystal field, well-resolved emissions from lanthanide-doped LiYF4 crystals were studied, and highly polarized UC emissions from Er3+ and Ho3+ were investigated. With multiple sub-energy level transitions, the UC emissions are classified into two sets, with transition dipoles being either parallel or perpendicular to the c-axis of the LiYF4 crystal. An optical three-dimensional orientation sensor was further investigated, in which the in-plane angle is referenced from the orientation of the transition dipoles. In contrast, the out-of-plane angle can be deduced from the change in the degree of polarization. This research deepens our understanding of the polarized photoluminescence, and it opens up an avenue toward unique UC orientation sensors.

NaMgF3 -based phosphors have been described frequently in the literature. Their synthesis faces difficulties typical of fluoride materials. A simple precipitation synthesis for NaMgF3 -based phosphors is described in this paper. This consisted of mixing aq. NaF and MgCl2 /MgSO4 solutions. Various activators could be incorporated by adding the required salts during this process. Characteristic emission of the activators was observed in the prepared phosphors. As-prepared samples exhibited predominantly trivalent lanthanide emission. After thermal treatment in a reductive atmosphere, europium-doped samples showed the intense emission of Eu2+ . By virtue of the intense nature of the emission, lifetime measurements could be made for this sample. Notably, intense thermoluminescence and optically stimulated luminescence were observed in NaMgF3 :Eu. A simple, fast method for the synthesis of NaMgF3 was therefore developed.

Lanthanide (Ln3+)-doped near infrared (NIR)-II luminescent nanoprobes have shown great promise in many technological fields, but are currently limited by the low absorption efficiency of Ln3+ due to the forbidden 4f→4f transition. Herein, we report a novel NIR-II luminescent nanoprobe based on efficient energy transfer from Ce3+ to Er3+ and Nd3+ in sub-10 nm SrS nanocrystals (NCs), which are excitable by using a commercial blue light-emitting diode (LED). Through sensitization by the allowed 4f→5d transition of Ce3+, the NCs exhibit strong NIR-II luminescence from Er3+ and Nd3+ with quantum yields of 2.9% and 2.3%, respectively. Furthermore, by utilizing the intense NIR-II luminescence of Er3+ from the thermally coupled Stark sublevels of 4I13/2, we demonstrate the application of SrS:Ce3+/Er3+ NCs as blue-LED-excitable NIR-II luminescent nanoprobes for ratiometric thermal sensing. These findings reveal the unique advantages of SrS:Ln3+ NCs in NIR-II luminescence, which may open up a new avenue for exploring novel and versatile luminescent nanoprobes based on Ln3+-doped sulphide NCs.

P2-type layered manganese oxides are recognized as one of the most compelling cathode candidates for sodium-ion batteries, but these materials suffer from the intrinsic structural Jahn-Teller distortion and oxygen loss, which causes limited rate capability and long-cycle fading under a wide potential window. Here we demonstrate a new approach to realize a simultaneous enhancement on both rate performance and long-term duration over a wide potential window through dilute La lattice doping and perovskite surface modification. We reveal for the first time through both DFT calculations and experimental results, that the La-doping and perovskite LCM surface decoration can efficiently suppress oxygen loss by providing O 2p holes and oxygen vacancies, and meanwhile enhance the electronic and ionic conductivity. The as achieved LNCM/LCM (LaNa0.06Co0.06Mn0.88O3/ Na0.56Co0.17Mn0.8La0.03O2) demonstrates a record high rate performance of 20C (1C=180 mA g−1) and outstanding cycling performance of 300 cycles (70% capacity retention) at a wide potential range (1.5-4.4V), which outperform the state-of-the-art Mn-based layered oxides. We confirm the reversible solid solution reaction during the charge/discharge process using the operando synchrotron XRD analysis. This work demonstrates an applicable approach to realize significant improvement on both rate capability and cycle stability without sacrificing the potential window.

Summary Lanthanoid chelating tags (LCTs) are widely used for advanced paramagnetic NMR of biomacromolecules. The magnitude of their induced pseudocontact shifts (PCSs) and residual dipolar couplings (RDCs) depends critically on the anisotropy of the magnetic susceptibility tensor, which is usually determined by the resonances of the conjugated protein, inevitably reducing the effect by motional averaging. Here, for the first time, we present the intrinsic anisotropy parameters for the full lanthanoid series determined experimentally from resonances on the ligand itself. The strongly shifted proton spectra could only be assigned by extensive, site-specific isotope labeling. The extremely large anisotropies obtained deliver an upper limit for future PCS applications. To our great surprise, at least at room temperature, we observed an unprecedented correlation between the oblate or prolate f-electron distribution of the lanthanoid and the orientation of the main magnetic axis as well as the size of the magnetic anisotropy.

Silicon-based clusters have attracted particular attention because they are regard as building blocks for developing silicon-based nanomaterials. However, pure silicon clusters have low chemical stability owing to their dangling bonds. Doping with lanthanide atoms is a good way to form closed-shell of M@Sin clusters and alter their electronic and magnetic properties. Here, we systematically study the lanthanide element Pr doped neutral and anionic silicon clusters by using density functional theory. Extensive searches for ground-state structures of Sin+1λ and PrSinλ (n = 1–9, λ = 0, − 1) clusters were carried out based on the comparison between experimental photoelectron spectroscopy and simulated spectra. Furthermore, the calculated AEA values of our obtained structures show good agreement with the experimental values. Based on averaged binding energies, fragmentation energies and HOMO–LUMO gaps, their relative stabilities were analyzed. Furthermore, the patterns of HOMOs for the most stable isomers were investigated to gain insight into the nature of bonding. The results show that some σ-type and few π-type bonds are formed among Si and Pr atoms. To achieve a insight into localization of charge and charge-transfer information, the Mulliken population are analyzed and discussed.

There is a need to develop new solid-phase adsorbents to extract elements from the coal ash. High surface area carbon adsorbents are remarkably good at adsorption of rare earth elements and have good stability in acidic media. A high surface area (1162 m2/g), surface-oxidized microsphere flower carbon (MFC-O) has been prepared for the extraction of rare earth elements as well as thorium and uranium. MFC-O exhibits outstanding distribution coefficients up to kd = 1.2 × 106 for thorium, uranium, and rare earth elements. It was found that thorium and uranium can be separated from the rare earth elements by adjusting the pH. The maximum extraction capacity (71.3 mg/g) was performed up to 88 ppm with 18 competitive elements (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, and U), and element recovery was >85%. A coal ash sample (NIST SRM 1633c) with a known concentration of elements (Na, Ca, Al, Si, Fe, Sc, La, Ce, Nd, Sm, Eu, Tb, Dy, Yb, Lu, Th, and U) was leeched resulting in 45% Ce recovery. The leeched solution from NIST 1633c was then mixed with MFC-O for Ce extraction of 74%, Na (17%), Ca (13%), Al (24%), Si (41%), and Fe (17%). The binding properties of MFC-O show that it is an attractive material for the selective extraction of rare earth elements from coal ash.

The plentiful structural features and excellent fluorescence properties of lanthanide coordination polymers (Ln-CPs) have garnered much attention in recent years. Herein, 1,4-naphthalic acid (1,4-N...

We have developed a facile strategy to fabricate model multicolor hydrogels via a straightforward mixing process of poly acrylonitrile-grafted methacrylamide (PANMAM), polymethacrylic acid (PMAA) and doped lanthanide (Eu/Tb) and zinc ions to form the interpenetrating dual-polymer gel networks. The hydrogels exhibit excellent tunability of multi-spectrum emission colors (including white light) by simply varying the stoichiometry of metal ions. Furthermore, taking the advantage of different metal ion response mechanisms, we have demonstrated the reversible acidity/alkalinity stimuli-responsive behaviors of white-light-emitting hydrogel (WLE gel). Meanwhile, the unique cross-linked network formed through hydrogen-bonding, metal-ligand coordination and ionic interaction is introduced to achieve favorable mechanical strength of hydrogels. These properties enable the possibility in obtaining fluorescent patterns on hydrogels, which are promising candidate for encrypted information with improved security.

In this present exploration, chitosan doped with different lanthanide oxides such as CeO2, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Dy2O3 and Ho2O3 has been prepared and its optical and thermodynamical properties were studied as a function of the ion size of the lanthanide element and its atomic masses. From the refractive index measurement, the space-filling factor and polarizability have been obtained. The propagation of ultrasonic waves like ultrasonic velocity and its derived quantities such as relaxation strength (rs), adiabatic bulk modulus (Ks), acoustic impedance (Z) and adiabatic compressibility (β) have been obtained for different Chitosan-Lanthanide oxides (Ch-LnO). FTIR studies confirm the formation of different Ch-LnO. The variation of all the said properties with ion size is opposite to that of atomic mass due to lanthanide contraction. The results are presented and discussed in a detailed manner.

Three novel metal-organic coordination polymers based on sulfur-containing thieno[3,2-b]thiophene-2,5-dicarboxylic (trans-H2ttdc) and thieno[2,3-b]thiophene-2,5-dicarboxylic (cis-H2ttdc) acids are obtained: [Ce2(DMF)4(trans-ttdc)3]·2DMF (1), [Dy2(DMF)4(trans-ttdc)3]·4DMF (2), and [Tb2(DMF)4(cis-ttdc)3]·2.5DMF (3). Structures of the products are determined by single crystal X-ray diffraction. The compositions and nature of compounds 2 and 3 are confirmed by IR spectroscopy, elemental and thermogravimetric analyses. All three compounds are based on binuclear {Ln2(DMF)4(RCOO)6} units organized into 3D frameworks with primitive cubic topology pcu by linear organic linkers. The specific void volume in the structures of 1-3 ranges from 29% to 37%.

Broadband sensitization is an effective strategy to enhance the upconversion luminescence (UCL) of lanthanide ions. Herein, novel UC materials LiScSi2O6:Cr3+/Er3+ (LSS:Cr3+/Er3+) were synthesized by high-temperature solid state reaction and their luminescent properties were investigated. LSS:Cr3+/Er3+ has the broadband absorption in the spectral range of 600–800 nm, and meanwhile shows green UC emissions of Er3+ upon pumping Cr3+ by the 690 nm laser. The UCL of LSS:Cr3+/Er3+ belongs to the two-photon process and is attributed to the energy transfer upconversion mechanism. The effects of the Cr3+ and Er3+ concentration as well as the Yb3+ introduction were also studied. LSS:Cr3+/Yb3+/Er3+ exhibits the interesting dual-mode UCL, capable of generating the UCL of Cr3+ upon pumping Yb3+ ions and the UCL of Er3+ upon pumping Cr3+ ions. This research might promote the development of novel broadband Cr3+-sensitized UC materials.

Lanthanide-based luminescent nanoparticles that are thermally responsive can be used to probe temperature changes at a nanoscale regime. However, materials that can work as both a nanothermometer and a catalyst are limited. Herein, we show that covalent organic frameworks (COFs), which is an emerging class of porous crystalline materials, can be grown around lanthanide nanoparticles to create unique core-shell nanostructures. In this way, the COF (shell) supports copper metal ions as catalytic sites and simultaneously lanthanide nanoparticles (β-NaLuF4:Gd,Er,Yb-core) locally measure the temperature during the catalytic reaction. Moreover, β-NaLuF4:Gd,Er,Yb nanoparticles are upconverting materials and hence can be excited at longer wavelengths (975 nm), which do not affect the catalysis substrates or the COF. As a proof-of-principle, a three-component addition reaction of benzaldehyde, indole, and malononitrile was studied. The local temperature was probed using luminescence nanothermometry during the catalytic reaction.

Modulating the optical property of a material via structural modification is a powerful tool for obtaining the desired optical output. If a material can be tuned inside (core) and outside (outer shell), then the degree of control is greater toward application. Herein, we present a lanthanide-based nanosized molecular cluster aggregate (MCA) that allows fine-tuning of the inner core via composition control akin to nanoparticles. At the same time, the tunable outer shell enables light-harvesting properties similar to molecular systems. As such {Eu4Tb16}, {Eu3Gd5Tb12}, {Eu2Gd10Tb8}, and {Eu1Gd15Tb4} compositions were synthesized, and their photophysical properties were investigated in solution and in the solid state. Controlling the composition and spacing of the emitter ions with the optically silent GdIII ions results in a decrease in the TbIII → EuIII energy-transfer process efficiency. Consequently, ratiometric luminescence thermometry performance is fine-tuned to reach a maximum relative sensitivity of 4.17% °C-1 at 36 °C for the {Eu4Tb16} MCA. This study demonstrates that the optical properties are intrinsic to individual MCA species rather than a collective intermolecular effect. The color change observed close to room temperature for {Eu2Gd10Tb8} suggests potential applications such as multistage anticounterfeiting technology.

Guided by a second-sphere interaction strategy, we fabricated a Tb(III)-based metal-organic framework (MMCF-4) for turn-on sensing of methyl amine with ultra-low detection limit and high turn-on efficiency. MMCF-4 features lanthanide nodes shielded in a nonacoordinate geometry along with secondary coordination spheres that are densely populated with H-bond interacting sites. Nonradiative routes were inhibited by binding-induced rigidification of the ligand on the second coordination sphere, resulting in luminescence amplification. Such remote interacting mechanism involved in the turn-on sensing event was confirmed by single-crystal X-ray diffraction and molecular dynamic simulation studies. The design of both primary and secondary coordination spheres of Tb(III) enabled the first turn-on sensing of organic amines in aqueous conditions. Our work suggests a promising strategy for high-performance turn-on sensing for Ln-MOFs and luminous materials driven by other metal chromophores.

The present work focuses on the hydrothermal synthesis and properties of porous coordination polymers of metal-porphyrin framework (MPF) type, namely, {[Pr-4 (H2TPPS)(3)]center dot 11H(2)O}(n) (UPJS-10), {[Eu/Sm(H2TPPS)]center dot H3O+center dot 16H(2)O}(n) (UPJS-11), and {[Ce-4(H2TPPS)(3)]center dot 11H(2)O}(n) (UPJS-12) (H2TPPS = 4,4',4 '',4'''-(porphyrin-5,10,15,20-tetrayptetrakisbenzenesulfonate(4)). The compounds were characterized using several analytical techniques: infrared spectroscopy, thermogravimetric measurements, elemental analysis, gas adsorption measurements, and single-crystal structure analysis (SXRD). The results of SXRD revealed a three-dimensional open porous framework containing crossing cavities propagating along all crystallographic axes. Coordination of H2TPPS4- ligands with Ln(III) ions leads to the formation of 1D polymeric chains propagating along the c crystallographic axis. Argon sorption measurements at -186 degrees C show that the activated MPFs have apparent BET surface areas of 260 m(2)g(-1) (UPJS-10) and 230 m(2) g(-1) (UPJS-12). Carbon dioxide adsorption isotherms at 0 degrees C show adsorption capacities up to 1 bar of 9.8 wt % for UPJS-10 and 8.6 wt % for UPJS-12. At a temperature of 20 degrees C, the respective CO2 adsorption capacities decreased to 6.95 and 5.99 wt %, respectively. The magnetic properties of UPJS-10 are characterized by the presence of a close-lying nonmagnetic ground singlet and excited doublet states in the electronic spectrum of Pr(III) ions. A much larger energy difference was suggested between the two lowest Kramers doublets of Ce(III) ions in UPJS - 12. Finally, the analysis of X-band EPR spectra revealed the presence of radical spins, which were tentatively assigned to be originating from the porphyrin ligands.

In targeting reduced valent lanthanide chalcogenides, we report the first nanoparticle synthesis of the mixed-valent ferromagnets Eu3 S4 and EuSm2 S4 . Using divalent lanthanide halides with bis(trimethylsilyl)sulfide and oleylamine, we prepared nanoparticles of EuS, Eu3 S4 , EuSm2 S4 , SmS1.9 , and Sm3 S4 . All nanoparticle phases were identified using powder X-ray diffraction, transmission electron microscopy was used to confirm morphology and nanoparticle size, and magnetic susceptibility measurements for determining the ordering temperatures and valence. The UV/Vis, Raman and X-ray photoelectron spectroscopies for each phase were compared. Surprisingly, the phase is influenced by the halide and the reaction temperature, where EuCl2 formed EuS while EuI2 formed Eu3 S4 , highlighting the role of kinetics in phase stabilization. Interestingly, at lower temperatures EuI2 initially forms EuS, and converts over time to Eu3 S4 .

Organic light-emitting diodes (OLEDs) have had commercial success in displays and lighting. Compared to red and green OLEDs, blue OLEDs are still the bottleneck because the high-energy and long-lived triplet exciton in traditional blue OLEDs causes the short operational lifetime of the device. As a new type emitter, lanthanide complexes with a 5d-4f transition could have short excited-state lifetimes on the order of nanoseconds. To achieve a high-efficiency 5d-4f transition, we systematically tuned the steric and electronic effects of tripodal tris(pyrazolyl)borate ligands and drew a full picture of their Ce(III) complexes. Intriguingly, all of these complexes show bright blue emission with high photoluminescence quantum yields exceeding 95% and short decay lifetimes of 35-73 ns both in the solid powder and in dichloromethane solutions. Using the Ce(III) complex emitter, we show a blue OLED with a maximum external quantum efficiency of 14.1% and a maximum luminance of 33,160 cd m-2, and the specific electroluminescence mechanism of direct exciton formation on the Ce(III) ion with a near-unity exciton utilization efficiency is also confirmed. The discovered photoluminescence and electroluminescence property-structure relationships may shed new light on the rational design of highly efficient lanthanide-based blue emitters and their optoelectronic devices such as OLEDs.

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.

Open metal site (OMS) seated in a luminescent lanthanide (Ln) metal center offers an opportunity for rationally tuning the spectroscopic behavior of lanthanide-organic frameworks aiming for a wide range of sensing applications. However, given the spherical nature of common coordination geometries of trivalent lanthanides and the generally strong Ln-O bonds, the lanthanide based OMS is rarely reported and difficult to be functionalized. We report here a unique europium-organic framework containing abundant quasi-OMS that is protected by an abnormal weak Eu-O bond. These quasi-OMSs offer reversible direct binding sites for water molecules probed by X-ray crystallography, leading to sensitive, visible, and ratiometric luminescent sensing toward humidity and water content in organic solvents. The specific recognition of water based on quasi-luminescent-OMSs gives rise to a superior water detection limit down to 0.0003% v/v, which is one order of magnitude lower than that of Karl Fischer method.

Determining the nature and extent of covalency of early actinide chemical bonding is a fundamentally important challenge. Recently, X-ray absorption, electron paramagnetic, and nuclear magnetic resonance spectroscopic studies have probed actinide-ligand covalency, largely confirming the paradigm of early actinide bonding varying from ionic to polarised-covalent, with this range sitting on the continuum between ionic lanthanide and more covalent d transition metal analogues. Here, we report measurement of the covalency of a terminal uranium(VI)-nitride by 15N nuclear magnetic resonance spectroscopy, and find an exceptional nitride chemical shift and chemical shift anisotropy. This redefines the 15N nuclear magnetic resonance spectroscopy parameter space, and experimentally confirms a prior computational prediction that the uranium(VI)-nitride triple bond is not only highly covalent, but, more so than d transition metal analogues. These results enable construction of general, predictive metal-ligand 15N chemical shift-bond order correlations, and reframe our understanding of actinide chemical bonding to guide future studies. Determining the covalency of actinide chemical bonding is a fundamentally important challenge. Here, the authors report a 15N nuclear magnetic resonance spectroscopy study of a terminal uranium-nitride, revealing exceptional NMR properties and covalency that redefine 15N NMR parameter space and actinide chemical bonding.