RE Doping Research Articles

Enhanced chemical mechanical polishing (CMP) performance of porous self-assembled spherical cerium oxide via RE(La/Pr/Nd) doping

With the linewidth of integrated circuits has progressively narrowed, imposing higher demands on the chemical mechanical polishing (CMP) process. Cerium oxide nanoparticles are widely used as abrasives in CMP, with their physical structure and the surface content of Ce3+ ions and oxygen vacancies directly affecting their CMP performance. Here in, we synthesized La/Pr/Nd doped CeO2 with the porous self-assembled spherical structures. Doping with La/Pr/Nd reduced the grain size of cerium oxide, increased its specific surface area, decreased the pore size, and increased the pore volume. HR-TEM analysis shows that the porous self-assembled spherical CeO2 primarily exposes the (111) crystal facet. Additionally, the density functional theory (DFT) calculation, XPS, H2-TPR and XANES analyses shown that doping of La/Pr/Nd facilitated the formation of oxygen vacancies and increased the Ce3+ content on the (111) crystal facet of the CeO2. La atoms are more likely to stabilize on the CeO2 (111) surface compared to Pr and Nd atoms. The CMP results indicated that, The La-CeO2 exhibited a higher MRR of 338 ± 7.54 nm/min, which is a 35 % increase compared to p-CeO2, and achieved superior surface roughness (Ra = 0.201 ± 0.010 nm).

Microwave-absorbing behavior of rare-earth-ion-doped copper manganese nanoferrites in X-band frequency

In this study, the technology important Cu0.5Mn0.5Fe2O4 and Cu0.5Mn0.5Fe1.80RE0.2O4 (RE = La, Gd, Nd, and Dy) nanoferrites were synthesized via sonochemical method and characterized to overcome the electromagnetic pollution problems. Crystalline, morphological, electrical, magnetic, and microwave-absorbing parameter were identified by doping of RE (La, Gd, Nd, and Dy) in Cu0.5Mn0.5Fe2O4 nanoferrites. The XRD analysis revealed a cubic spinel structure with a single-phase composition for Cu0.5Mn0.5Fe2O4 nanoferrites whereas Cu0.5Mn0.5Fe1.80RE0.2O4 (RE = La, Gd, Nd, and Dy) nanoferrites had a cubic structure with the presence of a secondary phase. SEM images confirmed the spherical shape of the particle and the grain size within the range of 19.25–28.19 nm, with elemental stoichiometry confirmed by EDS spectra. The dielectric constant and conductivity of Cu0.5Mn0.5Fe1.80RE0.2O4 nanoferrites were low at higher frequencies, which lead good candidates for microwave-absorbing technologies. The substitution of RE decreases saturation magnetization (43.38–23.96 emu/g) and squareness ratio values of prepared nanoferrites were less than 0.5. The SET values of the prepared nanoferrites were in the range of 32.31–41.81 dB. The minimal reflection loss (RL) values of Cu0.5Mn0.5Fe2O4 and Cu0.5Mn0.5Fe1.80RE0.2O4 nanoferrites were less than 10 dB and which indicated that the prepared nanoferrites possessed great potential for applications as microwave-absorbing materials.

Luminescence spectra and site-occupation of Eu3+ centres in lithium antimonate LiSbO3 lattice

It is a challenge to accurately determine the exact location of the rare earth ion (RE) in the lattice when there are significant differences in radius, electronegativity and valence between the lattice cation and the corresponding RE activator in a host material. This study presents the findings on the luminescence and site occupancy of Eu3+ emission centers in the lithium antimonate LiSbO3 lattice. The phase-formation, structures, elemental composition, band transition characteristics, luminescence properties, and lifetimes of the Eu3+-doped phosphors were investigated. Eu3+-doped LiSbO3 exhibits a typical 5D0→7F2 red luminescence transition at 613 nm. Site-selective excitation, luminescence, and decay properties at the 7F0→5D0 transition wavelength were measured using a tunable pulsed narrow-band dye laser. Two Eu3+ luminescence centers in LiSbO3 were identified across the temperature range from 10 K to 300 K. The doping of RE(Eu3+) in LiSbO3 consistently occupies two crystallographic positions of Li+ and Sb5+. Furthermore, the probability of RE(Eu3+) ions preferentially occupying the Li+ (M) sites is notably high. The decay curves and luminescence lifetimes of the two Eu3+ centers were determined. Drawing from the experimental data, we discuss the potential defects induced by Eu3+ doping in LiSbO3 and the mechanism of charge compensation. These results could be instrumental in the advancement of new RE-activated luminescent materials or serve as a reference for investigating the specific positioning of RE ions within a phosphor lattice.

Influence of Eu, Gd and Lu dopants on the properties of TiO2: A first-principles study

The present study investigates the electronic structure, magnetic properties, and optical performance of anatase TiO2 and pure TiO2 systems with the addition of rare earth elements RE (Eu/Gd/Lu). Using first-principles calculations based on density-functional theory, we explore the effects of RE doping on these systems. Our calculations reveal that the structural stability remains intact under the conditions of RE doping. The total magnetic moment is determined to be 2.987 μB, 6.052 μB, and 0 μB for Eu, Gd, and Lu-doped TiO2 respectively. Furthermore, the band gap of Eu/Gd/Lu-doped TiO2 decreases significantly to 1.91eV, 1.8eV, and 1.88eV, leading to a lower energy requirement for electron transition, as compared to the initial energy band gap of 2.31eV. The incorporation of rare earth elements also results in an increase in the number of valence and conduction band energy levels near the Fermi level, primarily influenced by orbital electrons in the 4f layer of the rare earth elements. Additionally, our findings demonstrate a remarkable shift towards the red region in the absorption spectrum of the Eu-TiO2 system, accompanied by a relatively long photocarrier lifetime. These characteristics suggest its potential as a photocatalyst with enhanced performance. Overall, this research provides valuable theoretical insights towards the development and synthesis of novel TiO2 photocatalysts.

Rare Earth Dopants Enhance Thermocatalytic Activity of Manganese Oxides on Corrugated Silica Carriers for Formaldehyde Degradation

AbstractThe development of high efficiency thermocatalysts remains a great challenge for gaseous formaldehyde elimination. Herein, rare earth‐doped manganese dioxide (RE‐MnO2) particles with sizes of approximately 200 nm were deposited on corrugated silica carrier (CSC) by using cerium or samarium as dopants. One part of rare earth ions in RE‐MnO2/CSC were substituted for the manganese ions in α‐MnO2, and the other part existed in the form of cerium oxide or samarium oxide. RE‐MnO2/CSC exhibited better thermocatalytic activity than MnO2/CSC. The formaldehyde removal efficiency over RE‐MnO2/CSC reached nearly 100 % even after cycle tests of 5 times. Both the cerium and samarium doping accelerated HCHO oxidation via increasing lattice oxygen and Mn4+ amounts, improving low‐temperature redox properties, and reducing apparent activation energy. Notably, the RE oxides in the catalysts played different roles in HCHO degradation. Samarium oxide did not possess thermocatalytic activity, while cerium oxide in RE‐MnO2/CSC participated directly in the formaldehyde degradation via the CeO2↔Ce2O3 redox reaction and facilitated the oxidation of Mn2O3 into MnO2. This work revealed the effect mechanisms of RE doping and RE oxide on the enhanced thermocatalytic activity, and provided a novel viewpoint to develop RE‐doped catalysts for formaldehyde removal.

A Comprehensive Review on Mechanisms and Applications of Rare‐Earth Based Perovskite Nanocrystals†

Comprehensive SummaryRare earth (RE) ions, with abundant 4f energy level and unique electronic arrangement, are considered as substitutes for Pb2+ in perovskite nanocrystals (PNCs), allowing for partial or complete replacement of lead and minimizing environmental impact. This review provides a comprehensive overview of the characteristics of RE‐doped PNCs, including up‐conversion luminescence, down‐conversion luminescence, and quantum confinement effects, etc. Additionally, RE doping has been found to effectively suppress defect formation, reduce nonradiative recombination, enhance photoluminescence quantum yield (PLQY), and even allow for controlling over the morphology of the nanocrystals. The review also highlights the recent advancements in lead‐free RE‐based perovskites, especially in the case of Eu‐based perovskites (CsEuBr3 and CsEuCl3). Furthermore, it briefly introduces the applications of PNCs in various fields, such as perovskite solar cells (PSCs), luminescent solar concentrators (LSCs), photodetectors (PDs), and light‐emitting diodes (LEDs). A systematic discussion on the luminescence mechanisms of RE‐doped PNCs and lead‐free RE‐based perovskites is provided, along with an outlook on future research directions. The ultimate goal of this review is to provide guidance for the development of RE‐based perovskite optoelectronic devices. Key ScientistsIn 2015, Kovalenko et al. pioneered the synthesis of lead‐based perovskite nanocrystals using the thermal injection method. Concurrently, Zhong et al. introduced the ligand‐assisted reprecipitation method. These methods have become the predominant approaches for fabricating lead‐based perovskite nanocrystals. In 2017, Song et al. successfully incorporated various rare earth ions (Ce3+, Sm3+, Eu3+, Tb3+, Dy3+, Er3+, and Yb3+) into CsPbCl3 perovskite nanocrystals. They also observed the quantum cutting effect induced by defect states, facilitated by the doping of Yb3+. Gamelin et al. subsequently proposed that CsPbCl3:Yb3+ nanocrystals exhibit quantum cutting effects due to the introduction of charge‐compensating defects (VPb), resulting in the formation of Yb3+‐VPb‐Yb3+ defect complexes with shallow defect levels. In 2020, Zhang et al. successfully doped Nd3+ into CsPbBr3, yielding blue luminescent nanocrystals with a central wavelength of 459 nm and up to 90% photo‐luminescence quantum yield (PLQY). In the same year, Yang et al. achieved the synthesis of pure phase CsEuCl3 perovskite nanocrystals for the first time. In 2022, Paik et al. synthesized Cs3LnCl6 (Ln = Y, Ce, Gd, Er, Tm, Yb, Eu, Tb) nanocrystals using the thermal injection method. In 2023, Zhang et al. successfully introduced Ni2+ doping into CsEuCl3, enhancing the PLQY of CsEuCl3 nanocrystals from 5% to 19.7%. This review focuses on the development history of perovskite nanocrystals, including rare earth‐doped lead‐based perovskite nanocrystals and rare earth‐based lead‐free perovskite nanocrystals, as well as their applications.

Rare Earth Metal (La, Ce, Nd, Eu) Doped Cu/Zr-PILC Catalysts for the Efficient NH3-SCR at Low Temperature

ABSTRACT A series of RE-3Cu/Zr-PILC (RE = La, Ce, Nd, Eu) catalysts were prepared via an impregnation method and activities for NH3-SCR were evaluated. The physicochemical properties of each catalyst were explored using XRD, BET, H2-TPR, NH3-TPD, XPS and in-situ DRIFTS techniques. The doping of RE had enhanced the NH3-SCR efficiency of 3Cu/Zr-PILC. Among them, the 6Ce-3Cu/Zr-PILC sample demonstrated exceptional performance, achieving NO conversion rates exceeding 90% within the temperature range of 250–350°C. Moreover, it reached its peak NO conversion rate of 96.3% at 300°C while maintaining an impressive resistance to SO2. According to the results of TPR, TPD and XPS analysis, the modification of RE (especially Ce) enhanced the redox properties, the surface acidity, the atomic ratio of Cu2+/Cu+ and the amount of surface chemisorbed oxygen in the 3Cu/Zr-PILC samples, all of these are favorable for the NH3-SCR reaction. Furthermore, in-situ DRIFTS analysis reveals that the NH3-SCR reaction of RE-3Cu/Zr-PILC samples at low temperatures is governed by the Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-R) mechanisms, with the L-H mechanism being the predominant factor.

Structural Instability Stimulated Heteroatoms Co‐Doping of 2D Quaternary Semiconductor for Optoelectronic Applications

AbstractAlthough the structural and electrical engineering of transition metal dichalcogenides using atomic doping or doping‐induced phase modulation can be used to attain high‐performance and wavelength‐tunable optoelectronic devices, accessible substitutional doping to overcome the large lattice mismatch between the host and guest atom‐related bonding states remains elusive. This study corroborates an innovative synthetic route for molybdenum disulfide (MoS2)‐derived two‐dimensional (2D) quaternary semiconductors substitutionally doped with Re and O using a solution‐based large‐area compatible approach combined with the thermal evaporation of dopants. The substitutional doping of Re into MoS2 crystals with a large lattice mismatch is effectively accomplished by adopting structurally unstable host films, resulting in the large‐scale synthesis of 2D quaternary multi‐layers with a Re doping concentration >10%. Comprehensive spectroscopic and microscopic evaluations are performed to determine the efficacy of the host films with structural instability for the synthesis of 2D RexMo(1‐x)O2yS2(1‐y) quaternary multi‐layers. The capability of the quaternary semiconductor for versatile nanophotonic devices is validated by ascertaining the simultaneous enhancement of the photoelectrical properties with wide‐range optical absorption and photoelectrochemical properties, as compared with those of their binary counterparts.

Preparation of RE/g-C3N4 Photocatalysts by Thermal Polycondensation Method and Its Properties

Graphite phase carbon nitride photocatalysts (RE/g-C3N4) doped with different rare earths (RE=La, Ce, Sm, Nd, Eu) were prepared by thermal polycondensation method using rare earth metal nitrate and melamine as raw materials. The photocatalytic performance of RE/g-C3N4 was studied through using photo-degradation reaction of methylene blue (MB) as the evaluation model. The effects of calcination temperature, rare earth elements type and doping ratio on the photocatalytic performance of g-C3N4 were studied. The microstructure of the samples were characterized by FESEM, XRD, UV-Vis, etc. The results show that RE doping can refine the grains and enhance the absorption of visible light. The performance of rare earth doped samples have a significantly improved compared with pure g-C3N4. The performance of La doped samples was better than that of Ce, Sm, Nd and Eu doped g-C3N4. As the temperature increases, the photocatalytic activity of La/g-C3N4 samples increases. When the La doping ratio is 4.0%, the calcination temperature is 590 °C, the degradation rate of The La/g-C3N4 photocatalyst to MB is up to 98.0% within 4 h under visible light irradiation.

Engineering of Vacancy Defects in WS2 Monolayer by Rare‐Earth (Er, Tm, Lu) Doping: A First‐Principles Study

Vacancy defects in two‐dimensional (2D) materials are critical to their properties. The substitutional doping in vacancy defects by rare‐earth atoms results in diverse material versatilities, but the effects and the corresponding mechanisms are far from being answered. Herein, the electronic and optical properties of vacancy defects and lanthanide rare‐earth (RE = Er, Tm, Lu) doping in WS2 monolayers are studied based on density functional theory with Hubbard correction (DFT + U). The formation energies of defective and doped systems are calculated under W‐rich and S‐rich conditions, respectively. The bandgap of WS2 with one W‐defect in a 4 × 4 × 1 supercell changes from direct to indirect, while S‐defect does not change the bandgap type of the supercell. When RE atoms are doped in the W‐defect, the bandgap returns to direct. WS2 supercells with intrinsic defects and Lu doped in [W] defect show the nonmagnetic property, while Er‐ and Tm‐doped supercells show obvious magnetic properties. The imaginary part of dielectric function and absorption coefficients increase drastically from visible to near‐infrared as RE atoms substitute W sites, and the bandgap shrinks due to the rise of the valance band maximum. This work proves RE doping in 2D WS2 is an effective technique for bandgap and carrier engineering.

Effects of alloying elements on the super-lattice intrinsic stacking fault energy and ideal shear strength of Ni3Al crystals

The effects of alloying elements (Re,W,Ti,Ta,andMo) on the super-lattice intrinsic stacking fault energy and ideal shear strength (σmax) of Ni3Al crystals at 0 K was studied through first-principles calculation. The calculated formation enthalpy of point defects reveals that single solute atoms (i.e., Re,W,Ti,Ta,andMo) tend to occupy the Al site, while solute–solute complex defects (i.e., Re-Re, Re-W, Re-Mo, Re-Ta, Re-Ti, W-Mo, W-Ta, W-Ti, Mo-Ta, Mo-Ti, and Ta-Ti) tend to occupy the Al-Al site. The addition of single solute atom can increase the unstable stacking fault energy and ideal shear strength (σmax) of perfect Ni3Al crystals. Therefore, the doping of a single solute atom is beneficial for the creep strengthening of Ni3Al crystals. Compared with the doping of W,Ti,Ta,andMo, the doping of Re can more effectively impede the nucleation and movement of dislocations of Ni3Al crystals. Through the careful comparison of the creep properties of Ni3Al crystals with solute–solute complex defects, a conclusion can be drawn that the doping of alloy elements W and Re exhibit similar strengthening effects on the creep properties of Ni3Al crystals. W can be preliminarily predicted to replace part of Re in Ni3Al crystals without affecting creep properties. In addition, comprehensive evaluation reveals that the weak interaction between solute–solute complex defects should improve the strengths of Ni3Al crystals to a certain extent.

Graphene dispersant-assisted in situ growth of Re-doped MoS2 nanosheets on carbon cloth and their performance for hydrogen evolution reaction

Uniform distribution of electrochemically active transition metal compounds on carbon cloth can effective improve their hydrogen evolution reaction (HER) performance, however, harsh chemical treatment of carbon substrates is always unavoidable during this process. Herein, a hydrogen protonated polyamino perylene bisimide (HAPBI) was used as interface active agent for the in situ growth of rhenium (Re) doped MoS2 nanosheets on carbon cloth (Re-MoS2/CC). HAPBI contains a large conjugated core and multiple cationic groups and has been shown to be an effective graphene dispersant. It endowed the carbon cloth excellent hydrophilicity through simple noncovalent functionalization and, meanwhile, provided sufficient active sites to anchor MoO42- and ReO4- via electrostatic interaction. Uniform and stable Re-MoS2/CC composites were facilely obtained by immersing carbon cloth in HAPBI solution followed by hydrothermal treatment in the precursor solution. The doping of Re induced the formation of 1 T phase MoS2, which reached about 40% in the mixture with 2H phase MoS2. Electrochemical measurements showed an overpotential of 183 mV at a current density of 10 mA cm−2 in 0.5 mol L-1 H2SO4 when the molar ratio of Re to Mo is 1:100. This strategy can be further extended to construct other electrocatalysts that using graphene, carbon nanotubes, etc. as conductive additives.

First-principles study of adsorption and sensing properties of Re and Tc-doped gallium nitride nanotube (GaNNT) for oil-dissolved gases

In this study, the density functional theory (DFT) method at the B3LYP-GD3BJ/def2svp level of computation was employed to elucidate the adsorption properties of oil-dissolved gases; ethyl (C2H2), methane (CH4), and hydrogen (H2) gas molecule on pure, rhenium (Re), and technetium (Tc) doped GaNNT. The results of the frontier molecular orbitals shows that the doping of Re and Tc on GaNNT surface increases the conductive and sensitivity properties of the surfaces towards the adsorption of investigated gas molecules. The Re doped on GaNNT (Re@GaNNT) surface enhances the stabilization of the donor and acceptor orbitals before and after the adsorption of the considered gas molecules. The DOS of each of these materials is influenced by the presence of dopants Re and Tc. The Re and Tc atoms significantly influenced the energy level in the DOS for the surfaces and complexes. The adsorption of gas molecules on GaNNT and its doped counterparts were analyzed and compared by calculating the adsorption energy of each structure to obtain the most stable adsorption structures. We calculated the adsorption energies and found that CH4 adsorbed positively in all systems, but H2 adsorbed more effectively on GaNNT with an Eads of −0.008 eV. Positive values for weak adsorption are the outcome of other adsorptions. Additionally, all systems experienced substantial adsorptions following the complexation of C2H2. The equivalent Eads for C2H2GaNNT, C2H2Re@GaNNT, and C2H2Tc@GaNNT are –32.550 eV, –32.061 eV, and −31.685 eV, respectively. GaNNT, on the other hand, is believed to adsorb C2H2 better than other systems, with an Eads of 32.550 eV. GaNNT is a better adsorbent for C2H2 and H2 with high and negative Eads, but it is inappropriate for CH4 sensing due to the weak adsorption and minimal conductivity change.

Density functional theory study of rare earth Y, Ce and La-catalyzed oxidation mechanism of Ta(1 0 0) and Ta(1 1 0) surfaces

The density functional theory (DFT) calculations were conducted to study the adsorption and diffusion of oxygen on Ta(100) and Ta(110) with and without the substitution of rare earth (RE, RE = Y, Ce and La) in the surface layer, which aims to reveal the possible RE-catalyzed oxidation mechanism of those two surfaces. The calculated results show that the oxygen atoms are preferentially adsorbed on the hollow site of clean Ta(100) and Ta(110). The RE doping in the subsurface layer weakens the adsorption strength of oxygen on Ta(110), while it has a negligible influence on that on Ta(100). In contrast, the substitution of RE in the surface layer can enhance the adsorption ability of oxygen atom on the two surfaces, which is also proved by the analysis of Bader charge and electron localization function. Additionally, the oxygen atoms are predicted to preferentially occupy the octahedral site in the subsurface of Ta slabs with and without RE doping. The investigations of oxygen diffusion behaviors indicate that the RE, especially for La, doping in the surface layer decrease the energy barrier of oxygen penetration into Ta surface, and thus catalyze the oxidation process of Ta slabs. Those results could help to provide a fundamental basis for comprehending the oxidation mechanism of Ta surface with RE doping.

Distribution coefficients for rare-earth doping in Y3Ga5O12 garnet: Comparison with Y3Al5O12

We present the distribution coefficient k in Y3Ga5O12 garnet (YGG) for a series of rare-earth dopants (RE = La, Ce, Nd, Eu, Tb, Er, and Lu), and compare the results with our previous data on RE-doped Y3Al5O12 garnet (YAG). Under our condition of flux growth, single crystals of undoped YGG show the shape of pure trapezohedron with {211} faces, whereas RE doping stabilizes {110} faces. This is to be compared with the case of YAG, where {110} was the dominant face in both undoped and RE-doped crystals. In RE-doped YGG, k remains near unity when the size mismatch between the dopant and host Y3+ ions is within about 3–4%, and drops off rapidly for larger dopants. This is in contrast to RE-doped YAG, where k decreases continuously from the smallest (Lu3+) to the largest (La3+) dopant. We find such distinct behaviors to be correlated with the reported solution energies for the series of RE ions in YAG and YGG.

First-principles study of structural, electronic and magnetic properties of transition metal doped Sc2CF2 MXene

The electronic and magnetic properties are investigated for pristine Sc2CF2, Sc2CF2-VSc (Sc2CF2 with single Sc vacancy), and Sc2CF2-dTM (Sc2CF2 doped with transitional metals TM, TM = Cr, Fe, Hf, Mn, Mo, Nb, Re, Ta, Ti, V, W, Y, or Zr) by first-principles calculation. The result indicates that Sc2CF2-dTM (TM = Ti, Zr, Nb, Hf, Ta, or W) monolayers are more stable than the other systems through the analysis of binding energies. The introduction of the Sc-vacancy and substitution doping of Hf, Mo, Nb, Re, Ta, Ti, W, or Zr atoms result in the semiconductor–metal transition for the Sc2CF2 monolayer, while the introduction of doped Cr, Fe or Y atoms doesn’t change the semiconductor character of Sc2CF2 monolayer and the introduction of doped V or Mn atoms results in the semimetal character. The substitution doping of V, Cr, Fe, or Mn atoms leads to significant magnetism. Charge transfer is further explored by the analysis of the charge density difference, the planar averaged charge density, and Bader charge. The effective mass and electron localization function are also analyzed.

Influence of RE (Pr3+, Er3+, Nd3+) doping on structural, vibrational and enhanced persistent photocatalytic properties of ZnO nanostructures

Rare earth (RE- Pr, Er and Nd) doped ZnO nanostructures were prepared through simple wet chemical precipitation route. The RE doping induced interesting morphological transition from spherical to flower like structures were analyzed. The X-ray diffraction (XRD) measurements revealed that the prepared materials were of highly crystalline in nature and RE dopant ions did not altered the crystal structure of ZnO. The microstrain of ZnO was altered with respect to the nature of dopants. In the case of the Pr doped ZnO, X-ray photoelectron spectroscopy (XPS) analysis confirmed that the dopant (Pr) ions successfully substituted in the ZnO lattice. Raman spectra revealed RE doping induced lower energy side shift and variation in intensity of the peaks related to the characteristic phonon modes of ZnO. In the case of Nd doped ZnO nanostructures, dopant induced suppression in classical Raman modes and evolution of multiphonon related modes were identified. Optical diffuse reflectance spectral (DRS) measurements, along with the characteristic excitonic band of ZnO, other bands associated to the transitions of 4f energy levels related to the RE ions were observed. The partially filled 4f orbitals led to the enhanced photocatalytic activity in RE doped ZnO nanostructures. The observed enhanced photocatalytic activity in RE doped ZnO when compared to bare ZnO was discussed. The decolorization efficiency of MB ensued the following order 96 > 94 > 86 > 78% for ZnErO, ZnNdO, ZnPrO and ZnO, respectively.

Structure and Property Modulations of 13Cr Stainless Steel Through Microgravity Solidification and Minor Ce Addition

Solidification controlling and RE doping are effective ways to manipulate the microstructures and performances of 13Cr martensitic stainless steel. In this work by Ying Ruan and co-workers, article number 2100062, the influences of microgravity solidification and Ce addition on microstructure refinement, inclusion spheroidization and mechanical properties of 13Cr steels were explored comparatively.

CoFe2-xRExO4 (RE=Dy, Yb, Gd) magnetic nanoparticles for biomedical applications

Nanoparticles with general formula CoFe2-xRExO4 (RE = Yb, Dy, Gd; x = 0.0–0.3) were synthesized by the co-precipitation and heat treated for potential application in magnetic hyperthermia. The influence of RE doping on structural, magnetic and thermal properties has been investigated. The RE cations enter the spinel lattice as detected by X-ray diffraction. Thermal treatment leads to thermodynamically stable and relaxed single-phase spinel structures only for lower RE content, x = 0.01–0.05. The annealed samples present higher mass magnetization values up to 83 Am2/kg. In the case of annealed samples saturation magnetization decreases linearly from 83 Am2/kg (x = 0.01) to about 60 Am2/kg (x = 0.30). Thermal treatment induces a reduction in coercivity from 60 to 100 mT for as-prepared samples to 18–33 mT for annealed samples. Heating efficiency, i.e., Specific Loss Power of all samples has been studied using both magnetometric and calorimetric method to examine the energy loss mechanisms.

Scalable Substitutional Re‐Doping and its Impact on the Optical and Electronic Properties of Tungsten Diselenide

Reliable, controlled doping of 2D transition metal dichalcogenides will enable the realization of next-generation electronic, logic-memory, and magnetic devices based on these materials. However, to date, accurate control over dopant concentration and scalability of the process remains a challenge. Here, a systematic study of scalable in situ doping of fully coalesced 2D WSe2 films with Re atoms via metal-organic chemical vapor deposition is reported. Dopant concentrations are uniformly distributed over the substrate surface, with precisely controlled concentrations down to <0.001%Re achieved by tuning the precursor partial pressure. Moreover, the impact of doping on morphological, chemical, optical, and electronic properties of WSe2 is elucidated with detailed experimental and theoretical examinations, confirming that the substitutional doping of Re at the W site leads to n-type behavior of WSe2 . Transport characteristics of fabricated back-gated field-effect-transistors are directly correlated to the dopant concentration, with degrading device performances for doping concentrations exceeding 1% of Re. The study demonstrates a viable approach to introducing true dopant-level impurities with high precision, which can be scaled up to batch production for applications beyond digital electronics.