Rare Earth Doping Research Articles

Boosting Photoluminescence of Rare-Earth-Based Double Perovskites by Isoelectronic Doping of ns2 Metal Ions.

Doping of ns2 metal ions as an energy transfer (ET) bridge can significantly elevate the photoluminescence properties. Nonetheless, the fundamental influence of ns2 metal ions on the local lattice structures remains unclear, hindering the advancement of functional materials. Herein, Sb3+ doped rare earth double perovskites is employed as a typical case to demonstrate this issue. It is found that the isoelectronic doping of Sb3+ ions not only enhances the ET efficiency but also changes their localized electronic and lattice structures. Both density functional theory (DFT) and Judd-Ofelt (J-O) theory calculations provide unambiguous evidence that the isoelectronic doping of Sb3+ ions enables a more localized charge density in the [LnCl6]3- (Ln: Lanthanide) octahedron and reduces the symmetry of the environment around the Ln3+, facilitating the radiative transition rates of Ln3+ while enhancing their ET efficiency. Compared with Cs2NaScCl6:Ln3+, the ET efficiency of Cs2NaScCl6:Sb3+/Ln3+ is enhanced by 1.5-fold, reaching up to 98.3%. To the best of available knowledge, this work is the first to unravel the intrinsic mechanism of enhanced ET process enabled by isoelectronic doping via DFT and J-O theory. This research sheds light on understanding the mechanism of photophysics and rational design of the functional perovskite materials.

Superior Piezoelectric Performance in Textured CaBi2Nb2O9 Ferroelectric Ceramics through Rare-Earth Gadolinium Doping and Spark Plasma Sintering.

High-performance piezoelectric ceramics with excellent thermal stability are crucial for high-temperature piezoelectric sensor applications. However, conventional fabrication processes offer limited enhancements in piezoelectric performance. In this study, we achieved a significant breakthrough in the piezoelectric performance of highly textured CaBi2Nb2O9 (CBN) ceramics by incorporating rare-earth gadolinium doping and utilizing spark plasma sintering. The resulting Ca0.97Gd0.03Bi2Nb2O9 (CBN-3Gd) ceramics exhibited superior piezoelectric properties, with a high piezoelectric constant d33 of 26 pC/N and a high Curie temperature TC of 946 °C. We employed piezoresponse force microscopy (PFM) to observe the morphology and dimensions of the ferroelectric domains, revealing a rod-shaped 3D domain configuration. This configuration facilitated polarization rotation in the textured ceramics, as analyzed using X-ray photoelectron spectroscopy (XPS) and polarization-electric field (P-E) hysteresis loops. Furthermore, the textured CBN-3Gd ceramics demonstrated exceptional thermal stability and reliability. The piezoelectric constant d33 decreased by only 11.8% over a temperature range of room temperature to 500 °C, and the DC electrical resistivity remained at 6.7 × 105 Ω cm at 600 °C. This work not only highlights the great potential of textured CBN-based ceramics for high-temperature piezoelectric sensors but also provides a viable strategy for enhancing the performance of piezoelectric materials with large aspect ratio micromorphology.

Lanthanide Functionalized Carbon Quantum Dots for White Light Emission, pH Sensing, and Co (II) Detection.

Carbon quantum dots (CQDs) with fluorescence emission have been widely studied for versatile applications, but facile tunability of the spectral properties of CQDs by doping remains to be further explored. Herein, employing lanthanide ion Eu3+ as a dopant and activator, a simple and efficient synthesis route for pure CQDs and Eu-CQDs was demonstrated using N, N-dimethylformamide, oleic acid, and oleylamine as precursors for carbon sources. In comparison, with the popular citric acid precursor, the as-prepared CQDs and Eu-CQDs exhibited an obviously smaller particle size (1.72 ± 0.29 nm) and a more uniform distribution. Through systematic optimization of Eu3+ doping for the Eu-CQD system, colorful light emissions in the visible range were first realized under excitation of ultraviolet (UV) ∼360 nm for promising application of UV-triggered light-emitting diodes. Most interestingly, this Eu-CQD solution with UV-excited colorful light emissions was utilized as a visual pH sensor, experimentally featuring good repeatabilities and stabilities (pH values switching between 7 and 14). Besides, the Eu-CQD solution exhibited highly sensitive detection characteristics for Co (II) ions. Due to the spectral overlapping, the quenching efficiency is as high as 96.3%, and the detection limit is obtained as 0.139 μM, which is much lower than the maximum concentration of Co (II) in the drinking water permitted by WHO. All of these relevant results significantly demonstrate the great potential of lanthanide doping in the multifunctionalization of CQDs for certain emerging applications like lighting, sensing, and detection.

Upconversion photoluminescence of Er-doped Bi$_{4}$Ti$_{3}$O$_{12}$ ceramics enhanced by vacancy clusters revealed by positron annihilation spectroscopy

Abstract Doping of rare earth elements into Bi$_{4}$Ti$_{3}$O$_{12}$ can significantly enhance the upconversion photoluminescence (UCPL) properties, but its structure-property relationship is still unclear. In this work, Er-doped bismuth titanate Bi$_{4-x}$Er$_{x}$Ti$_{3}$O$_{12}$ ($x$=0, 0.1, 0.2, 0.3, 0.4, 0.5) ceramics were synthesized via solid-state reaction method. The X-ray diffraction analysis confirmed the orthorhombic crystalline structure of the Bi$_{4-x}$Er$_{x}$Ti$_{3}$O$_{12}$ ceramics without any secondary phases. Experiments and calculations of positron annihilation spectroscopy were carried out to characterize their defect structure. The comparison between the experimental and calculated lifetime revealed that vacancy clusters were the main defects in the ceramics. The increase of the intensity of the second positron lifetime component (I$_{2}$) of Bi$_{3.5}$Er$_{0.5}$Ti$_{3}$O$_{12}$ ceramics indicated the presence of a high concentration of vacancy clusters. The UCPL spectra shown the sudden enhanced UCPL performance in Bi$_{3.7}$Er$_{0.3}$Ti$_{3}$O$_{12}$ and Bi$_{3.5}$Er$_{0.5}$Ti$_{3}$O$_{12}$ ceramics, which were consistent with the variation of the second positron lifetime component (I$_{2}$). These results indicate that the enhanced UCPL properties are influenced not only by the concentrations of rare earth ions but also by the concentration of vacancy clusters present within the ceramics.

First-principles study on lanthanide dopants in BaTiO3

Using first-principles calculation based on density-functional theory and density-functional perturbation theory, the microscopic structure and dielectric properties of Lanthanide (Ln) doped BaTiO3 are investigated. The doped Ln atoms exhibit significant displacement from Ba sites for charge compensation, forming off-centered configurations. This displacement is more pronounced for elements with smaller ionic radii. The change in ionic dielectric constant is strongly correlated with Ln displacement and Ln ion radius. As Ln displacement (ionic radius) increases (decreases), Ln-doped BaTiO3 has a higher ionic dielectric constant. However, regardless of the Ln species, the added Ln reduces the ionic dielectric constant compared to pristine BaTiO3.

Rare earth element Ce-doped floral In2O3 with high sensing performance for n-butanol

Pure In2O3 and the graded flower-shaped In2O3 structures doped with Ce, a rare earth element, were synthesized by an easy-to-operate template-free hydrothermal method, and the high sensing performance of the sensor for n-butanol was investigated. The micro-morphology and elemental compositions of the samples and their valence states were characterized by XRD, SEM, TEM, XPS and other testing methods. The morphological and compositional characterization showed that Ce doping is able to cause lattice distortion, which affects the sensing performance. The gas-sensitive test results revealed that 3 wt% Ce-doped In2O3 has the best sensing performance. At the optimal operating temperature of 320 °C, the response of 3 wt% Ce-In2O3 to 100 ppm n-butanol was as high as 225.63, which was 3.7 times higher than that of the pure In2O3 sensor (60.36). In addition, the Ce-doped In2O3 sensor also exhibited excellent selectivity, repeatability, long-term stability, and large specific surface area (73.1104 m2g-1). This study enhances the understanding of the mechanism of rare earth element doping to improve gas-sensitive properties and provides a new effective strategy for designing high-performance gas-sensitive materials.It also provides new ideas for the efficient detection of the toxic gas n-butanol.

Thermal stability of dielectric properties of Dy-doped BaTiO3 for application in the ultra-thin multilayer ceramic capacitors

Rare earth elements are usually used to improve the performance of multilayer ceramic capacitors (MLCC), because their unique chemical and physical properties. Exploring the optimal method of rare earth doping is crucial to address the current performance deficiencies of MLCC. In this study, three samples with different doping levels of Dy and Ho selected to investigate the microstructure, dielectric performance, and reliability. Compared to the co-doping of Dy and Ho, excessive Dy doping exhibited better defect structure, resulting in smoother and more stable temperature coefficient of capacitance (TCC) curves and stronger suppression of oxygen vacancies. As the increase of Dy doping content, the activation energy of oxygen vacancies increased from 59.98 V/μm to 86.79 V/μm. This indicates that appropriate Dy doping has a superior effect on improving MLCC performance compared to co-doping systems. This work validates the complex defect structure induced by Dy doping and its improvement effect on MLCC performance, demonstrating the significant potential of Dy-doped MLCC.

A high toughness hydrogel with Dy3+ enhanced fluorescence properties: For visual Zn2+ detection

Rapid, portable, and sensitive detection of Zn2+ is crucial for human health. In this study, SA/PEG/Ln fluorescent hydrogels were synthesized via in situ polymerization with lanthanide metals (Tb3+/Dy3+) and PAM. The results demonstrated a significant improvement in mechanical properties (132.8 % increase in compressive properties) after rare earth doping. The addition of Dy3+ enhanced the fluorescence properties of the singly doped Tb3+ fluorescent hydrogel (maximum luminous intensity increased by 1900 cd). Monitoring changes in fluorescence intensity enabled the realization of Zn2+ detection, allowing for quick and accurate determination of zinc ion presence. Visual monitoring of Zn2+ was achieved with the assistance of a portable ultraviolet lamp.

Study on the effect of rare earth elements La, Ce, Y and Sc doping on the mechanical properties of aluminum–lithium alloys

In this paper, the effects of rare earth elements La, Ce, Sc, and Y on the bond strength of the aluminum–lithium alloy δ’ (Al3Li)/Al interface are investigated using first-principles calculations. The results show that the interfacial energy decreases after substitutional doping of Al atoms on both sides of the interface by rare earth elements, respectively, with values ranging from −2.0664 eV/Å2 to −1.9720 eV/Å2. The interfacial energy decreased by 2.0841 eV/Å2 and 2.0709 eV/Å2 when Ce and Sc elements replaced Al in the matrix, respectively. Uniaxial interfacial tensile simulations of Al/ Al3Li showed that the strain elongation of the material increased from 24 % to 42 % for the pure interface after doping with Sc elements at the interface. The same tensile tests yielded a maximum elongation at break of 3.25 % for Al-Li alloy after artificial aging at 0.6 % Sc content. Observation of the microstructure of the materials before and after rare earth doping using TEM reveals that the content of nanoscale Al3(Sc, Li) composite particles increases with the increase of Sc content after artificial aging at 185 °C for 10 h. Moreover, the presence of Al3Sc refines the precipitated phase of the alloy and improves the plastic toughness of the material.

Effects of doping of Sm, Y, Ce and La on crystal structure, phase and photocatalytic performance of TiO2 powders prepared by sol-gel method

In the present work, pure and 1 mol% samarium (Sm), yttrium(Y), lanthanum (La), cerium (Ce)-doped titanium dioxide (TiO2) powders were prepared by sol-gel method. Taking Methylene blue (MB) dye as degradation targets the photodegradation performance of the photocatalysts was studied. XRD spectra confirmed that the doping of rare earth elements (RE) could inhibit the transformation of TiO2 from anatase to rutile crystal at high temperature of 800 °C. XPS analyzed the chemical state of the elements in the powder. Characterization such as SEM and TEM found that the doping of the RE elements made the severely agglomerated particles become dispersed and refined, increased the specific surface area, and reduced the optical bandgap. Simulated visible light degradation results of MB showed that the degradation efficiency was significantly improved by doping of the RE elements, and the best efficiency is 88 % for Sm-doped TiO2 powder samples.

Boosted Near-Infrared Photothermal Conversion in Rare Earth Ions-Doped 2D SnSe Nanosheets for Solar-Powered Water Evaporation Systems.

Solar-powered water evaporation as a clean and abundant renewable energy-efficient desalination technology provides a promising strategy to solve the shortage of freshwater resources. However, the development and application of solar vapor technology are hindered by the relatively low near-infrared photothermal conversion efficiency of existing materials and the lack of effective improvement strategies. In this work, the conductivity characteristics of 2Dsemiconductors are capitalized on the high visible light absorption and ultra-low thermal. Specifically, rare-earth ion dopants into SnSe nanosheets, significantly boosting their near-infrared photothermal conversion efficiency and solar water evaporation performance are introduced. Remarkably, the photothermal conversion efficiency of the doped SnSe nanosheets surged from 51.56% to 82.11%, surpassing many previously reported photothermal materials. Furthermore, leveraging these nanosheets with enhanced photothermal conversion efficiency, a solar interfacial evaporation system is constructed. The evaporation rate of 2.17kgm-2h-1 and the efficiency of 96.5% can be achieved at one solar irradiance, and it also has good salt-resistance properties. The findings demonstrate the potential of rare earth ion-doped 2D semiconductor nanosheets in solar water evaporation, paving the way for future sustainable desalination solutions.

Increasing the Magnetic Transition Dipole Moment of Chiral Perovskite Through Eu3+ Doping

AbstractChiral hybrid organic‐inorganic perovskites (HOIPs) are widely investigated due to their superior chiroptical and chiral spintronic properties. Research on the enhancement of chiroptical performance is highly important for the real application of chiral HOIPs. This work employed a rare earth doping strategy to increase the magnetic transition dipole moment of chiral 2D HOIPs R‐/S‐NPB (NPB = 1‐(1‐naphthyl) ethylammonium lead bromide). Doping with Eu3+ does not change the original layered NPB microstructure, and R‐/S‐NPB‐Eu exhibited the magnetic dipole‐allowed transition luminescence of Eu3+ at 594 nm (5D0→7F1). Circular polarized luminescence (CPL) spectra combined with theoretical calculations and transient photoluminescence measurements indicated that the introduction of Eu3+ can enhance the magnetic transition dipole moment of R‐/S‐NPB, thus resulting in an unprecedented glum of 0.05. To the best of our knowledge, this is the highest value for chiral perovskite films. This work combines the unique and superior optoelectronic properties of rare‐earth ions with chiral perovskite and develops an efficient strategy to increase its anisotropy factor, which can accelerate the development of chiral optoelectronics and spintronics towards real application.

Construction of marigold-like ZnIn2S4@Tb-g-C3N4 heterojunction for facilitating photocatalytic degradation of tetracycline and tylosin under simulated solar irradiation

Due to the high biological toxicity and the propensity to induce antibiotic resistance, the treatment of antibiotic wastewater has consistently posed a formidable challenge. The semiconductor photocatalysts can efficiently and completely remove antibiotics from the wastewater to repair the water environment. Therefore, a novel ZnIn2S4/Tb-g-C3N4 (ZIS/TCN) photocatalyst was successfully synthesized in this paper and its ability to efficiently degrade antibiotics has been verified. The optimized 150ZIS/TCN photocatalyst showed excellent photocatalytic performance and stablility toward the degradation of tetracycline (TC) and tylosin (TYL) under sunlight simulated with a xenon lamp. Compared with pristine g-C3N4 and ZnIn2S4, the 150ZIS/TCN exhibited superior degradation performance for TC (TYL)，about 3.2 (2.1) and 1.8 (1.5) times higher than them. Based on density functional theory (DFT) calculations and experimental characterization test results, it was confirmed that the Tb doping effectively regulates the intrinsic electric field and visible light absorption capacity. This study unveils the degradation mechanism of ZIS/TCN photocatalysis and provides an effective pathway for enhancing photocatalytic degradation through rare earth doping.

Synthesis and Upconversion Luminescence Fine-tuning of Yb3+/Ho3+-Doped Indium and Gallium Oxide Nanoparticles.

Rare earth (RE) dopants can modulate the bandgap of oxides of indium and gallium and provide extra upconversion luminescence (UCL) abilities. However, relevant UCL fine-tuning strategies and energy mechanisms have been less studied. In this research, InGaO, Ho3+ monodoped and Yb3+/Ho3+ codoped In2O3, and Ho3+ monodoped Yb3Ga5O12 nanoparticles (NPs) were synthesized by a solvothermal method. The effects of Yb3+ and Ho3+ dopants on the crystal structures, UCL properties, and optical bandgaps of the oxides were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UCL spectroscopy, and measurements of decay times, pump power dependence, and transmittance spectra. The crystal structures of oxide products of indium and gallium were significantly modified with RE dopants. In2O3 and Yb3Ga5O12 were selected as the host materials. For Yb3+/Ho3+ codoped In2O3 NPs, there existed energy transfers from the defect states of In2O3 to Ho3+ and from Yb3+ to Ho3+. With a fixed Ho3+ concentration, In2O3:0%Yb3+,2%Ho3+ NPs showed the optimal UCL properties mainly due to In2O3-Ho3+ energy transfer and Ho3+-Yb3+ energy-back-transfer, while with a fixed Yb3+ concentration, In2O3:5%Yb3+,3%Ho3+ NPs with a slight Yb2O3 impurity and Yb3Ga5O12:2%Ho3+ NPs did mainly due to Ho3+-Ho3+ cross-relaxation. Besides, the optical bandgaps of In2O3 and Yb3Ga5O12 were noticeably broadened with RE dopants. These findings can offer feasible directions for the synthesis and UCL fine-tuning of RE-doped oxides of indium and gallium and improve their multifunction application prospects in the fields of semiconductor and UCL nanomaterials.

Impact of Eu3⁺ on the self-crystallization of CsPbBr1.5Cl1.5 in glass-ceramics for precision temperature sensing applications

All-inorganic perovskite QDs, such as CsPbX3(X = Cl, Br, I), have garnered significant attention in the field of optoelectronics as emerging photonic materials. Rare-earth (RE) doping is an effective strategy for enhancing the optical properties of CsPbX3 perovskite quantum dot glasses. Therefore, investigating the crystallization behavior of rare-earth ion-doped CsPbX3 glass and the energy transfer mechanisms between rare-earth ions and CsPbX3 is crucial for advancing the development of rare-earth-doped perovskite glass materials. The paper systematically introduces the preparation methods, structural characteristics, and applications of CsPbBr1.5Cl1.5 QDs in optoelectronic devices. Firstly, the detailed effects of Eu3+ and F⁻ doping on the structure and optical properties of CsPbBr1.5Cl1.5 quantum dot glass are discussed. Subsequently, the crystal structure, size distribution, and morphology of CsPbBr1.5Cl1.5 QDs are characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Furthermore, the application of CsPbBr1.5Cl1.5 QDs in LEDs and temperature sensing optoelectronic devices is explored, highlighting their performance and potential value in these applications. This study provides important references and guidance for further research and application of CsPbBr1.5Cl1.5 QDs in the field of optoelectronics.

Rare earth Nd3+-doped organic-inorganic hybrid perovskite quantum dots for white LED

Lead halide perovskite quantum dots (QDs) have garnered significant attention due to their tunable band gaps, unique quantum confinement effects, and high photoluminescence quantum yields (PLQYs). Among them, Organic-inorganic QDs make them promising candidates for optoelectronic devices such as quantum dot light-emitting diodes (QLEDs), solar cells, lasers, and photodetectors. However, the toxicity of lead (Pb) has raised environmental and health concerns, hindering their industrial application. To alleviate concerns about heavy metals Pb, extensive research has been conducted on B-site doping and the development of lead-free perovskites. Herein, we firstly developed B-site doping strategy on organic-inorganic hybrid perovskite QDs via rare-earth elements. Neodymium (III) (Nd3+) doped FAPbBr3 QDs were prepared through the ligand-assisted reprecipitation method at room temperature. The B-site doping strategy could alleviate the heavy metal problem of Pb and modulate the band gap of FAPbBr3 QDs facilely. The results demonstrated that increasing the concentration of Nd³⁺ can change the emission of FAPbBr₃ QDs from pure green to deep blue. Specifically, we achieved highly pure blue emission (∼438 nm) with a full width at half maximum (FWHM) of 13 nm for Nd³⁺-doped FAPbBr₃ QDs. Time-resolved photoluminescence (TRPL) spectroscopy revealed a decrease in the lifetime of FAPbBr₃ QDs from 22.86 to 15.46 ns as the doping concentration increased. Additionally, we fabricated a white LED (WLED) utilizing blue-emitting Nd³⁺-doped FAPbBr₃, green-emitting FAPbBr₃ QDs, and red QDs, achieving a white emission color coordinate of (0.33, 0.36). This study pioneers the application of B-site rare-earth doping in organic-inorganic hybrid perovskite QDs, demonstrating that B-site composition engineering is a reliable strategy to further exploit the perovskite family for wider optoelectronic applications.

Enhancement in power factor through rare-earth samarium doping in Cu2SnSe3 system

Cu2SnSe3 has drawn enough attention as a potential thermoelectric material due to its unique electronic and thermal properties. We present the impact of Sm doping on the Cu2SnSe3 system’s Sn site. The polycrystalline samples of Cu2Sn1-x Sm x Se3 (0 ≤ x ≤ 0.08) were prepared using the solid-state reaction technique followed by conventional sintering. The crystal structure was characterized using XRD and the results reveal that the samples have a diamond cubic structure with a space group of F4̄3m. Scanning Electron Microscopy (SEM) analysis indicates a uniform surface homogeneity within the sample. Furthermore, the introduction of Sm causes a reduction in porosity. The electrical transport characteristics were studied in the mid temperature range of 300–650 K. The Seebeck coefficient of all the samples were found to be positive within the temperature range under study, suggesting that holes constitute the majority charge carriers. This is also confirmed by the Hall measurements as the carrier concentration was positive for all the samples. The inclusion of Sm has led to a reduction of electrical resistivity and Seebeck coefficient and hence power factor of ~539 μW mK−2 for x = 0.08 at 630 K which is ten times greater as compared to x = 0 whose power factor is ~56 μW mK−2 at 630 K is achieved which makes it suitable for thermoelectric applications.

Enhancing the luminescent properties of strontium phosphate glass via controlled crystallization and rare earth dopants

The study focused on investigating the photoluminescence behavior of pure strontium phosphate glasses with a composition of 62.5% P2O5 and 37.5% SrO. Then it was extended to investigate the effects of adding rare earth elements (Pr3+, Sm3+, Eu3+, Dy3+) and the crystallization process on improving luminescent properties of the parent glass. Various spectroscopic measurements, including XRD, SEM & EDAX, and FTIR, were conducted to examine the relationship between structural changes and their impact on luminescent performance. The optical measurements showed a characteristic enhancement resulting from the addition of RE3+-dopants and the crystallization process. The crystallization of glasses yielded a single phase from Sr(PO3)2 with an extended emission peak at 671 nm and heightened intensity compared to the glassy sample. The development of efficient and stable luminescent glasses via crystallization and dopant type can lead to advancements in applications such as glowing devices, optical detectors, and photonics innovations.

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In article number EOM2_EV_EOM212484, Ashishi Gaur and co‐workers report a compressive review on effects of lanthanide doping in electrocatalysts for water splitting. This review covers the mechanistic aspects, followed by recent advancements in lanthanide doping and heterostructure formation for water electrolysis applications image

Lanthanides in the water electrolysis

AbstractThe most feasible technique for producing green hydrogen is water electrolysis. In recent years, there has been significant study conducted on the use of transition metal compounds as electrocatalysts for both anodes and cathodes. Peoples have attempted several strategies to improve the electrocatalytic activity of their original structure. One such technique involves introducing rare earth metals or creating heterostructures with compounds based on rare earth metals. The incorporation of rare earth metals significantly enhances the activity by many folds, while their compounds offer structural stability and the ability to manipulate the electronic properties of the original system. These factors have led to a recent boom in investigations on rare earth metal‐based electrocatalysts. There is currently a pressing demand for a review article that can provide a comprehensive overview of the scientific advancements and elucidate the mechanistic aspects of the impact of lanthanide doping. This review begins by explaining the electronic structure of the lanthanides. We next examine the mechanistic aspects, followed by recent advancements in lanthanide doping and heterostructure formation for water electrolysis applications. It is expected that this particular effort will benefit a broad audience and stimulate more research in this area of interest.image