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1540 nm lasers are widely used for excellent anti-interference capability and atmospheric transmission, whose corresponding suppressing materials are still lack of investigation Er3+ ions can effectively absorb 1540 nm lasers due to energy level transitions near this wavelength. And the absorption effect could be further enhanced by doping with heterogeneous metal ions. Herein, Co2+ has been doped into ErBO 3 with different concentrations, which could induce lattice contraction of Er3+ ion cells. The ErBO 3 samples prepared by solvothermal and calcination processes are characterized by "flower-like" porous microspheres at 800 °C. The influence of different calcination temperatures and molar ratios of raw materials on the reflection performance of 1540 nm laser light was examined. The laser reflectance of the sample was reduced to 0.707 % by doping with 20 mol% Co2+. This Co2+ doped ErBO 3 material exhibits significant potential in 1540 nm laser protection applications. [ABSTRACT FROM AUTHOR]

The realization of stable single‐component white light emission in metal halide perovskites is still challenging due to the fast halide ion migration and narrow luminescence bands. In this work, all‐inorganic single CsPbClxBr3−x perovskite microplates with stable red‐blue‐green triple color light emission are prepared by introducing europium ions Eu3+ as dopants. Eu doping effectively suppresses ion migration and enables two spatially separated halide phases with stable dual‐wavelength emissions. Furthermore, the incorporation of Eu3+ compensates for the absence of red‐light emission, thereby yielding a superior white emission with exceptional quality. The color rendering index of triple‐color‐emitting perovskites can be tuned successfully by controlling the halogen ratios, and the optimal microplate achieved a Commissions Internationale de l’Eclairage (CIE) coordinates of (0.32, 0.32). The results present a new enlightenment for the preparation of low‐cost single‐component white light materials. [ABSTRACT FROM AUTHOR]

Rapid capacity fading and structural collapse, along with other deep‐rooted challenges in the high‐voltage region, are insufficient to meet the requirements for commercial applications of O3‐type layered cathodes. Hereby, rare earth metal (RE) within the IIIB group are utilized as the robust dopants for O3‐NaNi1/3Fe1/3Mn1/3O2 (NFM) to achieve the purpose of reconstructing the crystal lattice and regulating the interlayer structure. The inactive RE3+ acts as a pillar, reinforces the TMO6 octahedron, and broadens the Na+ diffusion layer in the configuration of O‐Na‐O‐TM (RE)‐O‐Na‐O, giving rise to the enhanced crystal stability and accelerating the transmission of sodium ions. More impressively, the scandium incorporation is working as a "vitamin" that improves Ni/Fe redox reversibility, alleviating the irreversible P3‐O3'‐P3' phase transformation and further restraining the disordered Fe migration into the neighboring Na layer, which is firmly validated by in situ X‐ray diffraction coupled with the synchrotron X‐ray absorption spectroscopy. Consequently, the as‐designed NFM‐Sc exhibits impressive rate capability (82.5 mAh g−1 at 10 C) and excellent cycle stability with 80.2% capacity retention after 500 cycles at the high voltage of 4.2 V. Given this, the elaborate work may shed new insight into the operational mechanism of rare metal through strategically regulating the structure for sodium‐ion batteries. [ABSTRACT FROM AUTHOR]

In this study, original titanium dioxide (TiO2) and cerium (Ce)-doped TiO2 nanorod array photoanodes are prepared by hydrothermal method combined with high-temperature annealing, and their morphology, photoelectrochemical properties, and photocatalytic hydrogen production ability are systematically evaluated. X-ray diffraction (XRD) analysis shows that as the Ce content increases, the diffraction peak of the rutile phase (110) shifts towards lower angles, indicating the successful doping of different contents of Ce into the TiO2 lattice. Photoelectric performance test results show that Ce doping significantly improves the photocurrent density of TiO2, especially for the 0.54wt% Ce-doped TiO2 (denoted as CR5). The photocurrent density of CR5 reaches 1.98 mA/cm2 at a bias voltage of 1.23 V (relative to RHE), which is 2.6 times that of undoped TiO2 (denoted as R). Photoelectrochemical hydrolysis test results show that the hydrogen yield performance under full-spectrum testing conditions of Ce-doped TiO2 photoanodes is better than that of original TiO2 as well, which are 37.03 and 12.64 µmol·cm−2·h−1 for CR5 and R, respectively. These results indicate that Ce doping can effectively promote charge separation and improve hydrogen production efficiency by reducing resistance, accelerating charge transfer, and introducing new electronic energy levels. Our findings provide a new strategy for designing efficient photocatalysts with enhanced photoelectrochemical (PEC) water-splitting performance. [ABSTRACT FROM AUTHOR]

Partially stabilized zirconia （7YSZ） with a mass fraction of 7±1% yttrium oxide is a widely used ceramic material for thermal barrier coatings. However， its phase stability， sintering resistance， and mechanical properties decreased during the long-time operation above 1200 ℃. A new type of Sc2O3-Y2O3 co-doped ZrO2 thermal barrier coating ceramic material was proposed ， and a molar fraction of 7.5%Sc2O3-x%Y2O3-（92.5-x）%ZrO2（x=0，0.1，0.2，0.3） ceramics were prepared by solid-state reaction method. The effects of Y2O3 doping on the microstructural， phase evolution， and mechanical properties（including Vickers hardness， fracture toughness， elastic modulus and three-point bending strength）were explored by XRD， SEM， and other testing methods. The results show that the relative density of Sc2O3-Y2O3 doped ZrO2 ceramics sintered at 1450 °C for 3.5 h is more than 97%， and the phase structure is composed of tetragonal phase. Compared with 6-8YSZ ceramics， Sc2O3-Y2O3 doped ZrO2 ceramics exhibit similar Vickers hardness （13-14 GPa）， fracture toughness （6.5-7.0 MPa·m1/2）， elastic modulus （211-214 GPa）and three-point bending strength（520-850 MPa）. Fracture mechanism shows a mixture of transgranular and intergranular fracture modes， in which transgranular fracture is dominant.This ceramic can be explored as a potential thermal barrier coating material for high-temperature applications.

Lu 2 O 2 S has high density, high melting temperature, and favorable thermal stability, making it an excellent matrix material for rare earth luminescence and X-ray sensitization screens. However, achieving high quality fluorescent powders with high crystal quality on a large scale is still challenging. By employing an optimized solid phase approach, Lu 2 O 2 S:Tb3+/Sm3+phosphors with a hexagonal shape and uniform particle size and showing high crystallization have been successfully synthesized. Spectral analysis reveals energy interaction between Sm3+ and Tb3+ in the Lu 2 O 2 S system (multistage interaction), indicated by spectral overlap, relative changes in luminescence intensity, and lifetime decay. By changing the excitation wavelength and dopant concentration, multicolor phosphors such as yellow-–green, orange–red, and orange–yellow could be created. Temperature-dependent emission spectroscopy shows that the system shows good luminescence performance even at high temperatures. X-ray excitation spectroscopy further confirm that the phosphors emit different colors (yellow, green and red) depending on the doping concentrations of Tb3+ and Sm3+ ion, indicating that the system has wide application potential in color displays and other relevant fields. [ABSTRACT FROM AUTHOR]

The current research focuses on the synthesis of nickel spinel ferrite nanoparticles doped with rare earth elements via green synthesis-assisted sol-gel auto combustion method. X-ray diffraction (XRD), field electron scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectra were carried to examine the development of phase, morphology, and crystal structure. Structural parameters, cation distribution, and lattice strain were determined through Rietveld analysis and Williamson-Hall (W-H) plots. The lattice constant shows an increasing trend with increase in Tb3+ ion concentration. Using the G-Fourier technique, the electron density mapping of Nickel nano-ferrites replaced with rare earth (Tb) elements was computed. Saturation magnetization and magnetic hysteresis loss was found to decrease with Tb3+ addition. The insignificant hysteresis curve with small coercivity value and retentivity seen demonstrates the soft behavior. The room temperature resistivity values increase with the addition of terbium. The observed dielectric dispersion with frequency is explained by the Maxwell–Wagner two-layer model and the electron hopping mechanism, which are responsible for conduction and polarization. The dielectric constant and dielectric loss decrease with the addition of Tb3+, which can be attributed to a reduction in the hopping rate due to the substitution of Fe3+ ions by Tb3+ ions at the octahedral sites. The dielectric behavior of the NiTb0.1Fe1.9O4 composition exhibits a maximum dielectric constant value with a minimal loss tangent. The Cole-Cole plot highlights the role of grains and grain boundaries in the bulk material. Through impedance studies, the resistance and capacitance of both the grains and grain boundaries have been determined. The increased resistivity and reduced dielectric loss attained in Tb doped ferrite is promising as it is desirable for high frequency applications. Highlights: Synthesis of Tb doped nickel spinel ferrite nanoparticles via green synthesis-assisted sol-gel auto combustion method. The manifestation of paramagnetic behavior of Tb3+ ions at room temperature was corroborated from the magnetic study. The detailed dielectric dispersion is explained by the Maxwell–Wagner two-layer model and the electron hopping mechanism. The dielectric dispersion is responsible for conduction and polarization. The Cole-Cole plot highlights the role of grains and grain boundaries. The increased resistivity and reduced dielectric loss makes the material desirable for high frequency applications. [ABSTRACT FROM AUTHOR]

Cerate is regarded as a promising material for the next-generation of thermal barrier coating due to its high coefficient of thermal expansion (CTE) and low thermal conductivity. However, its thermal contraction within the temperature range of 473-673 K poses a significant challenge to its widespread application. The aim of this work is to improve the thermal contraction by regulating the configurational entropy of cerate ceramics. Six kinds of rare earth doped cerate ceramics with different configurational entropy were prepared. The results indicated that the phases of the as-prepared ceramics are all fluorite structures. With the increase of configurational entropy, the problem of thermal contraction is improved continuously. More importantly, the as-prepared (La 1/8 Sm 1/8 Yb 1/8 Y 1/8 Er 1/8 Eu 1/8 Nd 1/8 Gd 1/8) 2 Ce 2 O 7 (8RC) high entropy cerate ceramic demonstrates a near elimination of thermal contraction in the 473-673 K temperature range, and accompanied by high CTE, low thermal conductivity and good thermal stability, suggesting its potential application in the field of thermal barrier coating material. [ABSTRACT FROM AUTHOR]

The accumulation of heavy metal ions in the human body sharply affects health, drawing global attention. Consequently, there is an urgent need to develop environmentally-friendly and non-toxic metal ion fluorescent sensing probes. Herein, two fluorescent probes based on Cs–Bi–Cl perovskite quantum dots (PeQDs) with distinct structures, namely Cs 3 BiCl 6 :Eu3+ (3-1-6-E) and Cs 3 Bi 2 Cl 9 :Eu3+ (3-2-9-E), were successfully synthesized by using the ligand-assisted re-precipitation (LARP) method for detecting Cu2+ and Fe3+ ions in ethanol. Both PeQDs exhibit polychromatic emission, including feature emission around 505 nm and distinctive emission from Eu3+ ions in the long-wavelength region, making them suitable for ratiometric fluorescent probes. Significantly, both probes displayed excellent linear relationship with correlation coefficients of 0.998 (3-1-6-E) and 0.985 (3-2-9-E), respectively. The limit of detection (LOD) reached 6.23 μM (3-1-6-E) and 4.55 μM (3-2-9-E). Notably, the 3-2-9-E quantum dots (QDs) successfully detected Fe3+ ions in ethanol, owing to their unique photo-quenching and photo-recovery phenomena. The detection results exhibited excellent linear fitting, with a correlation coefficient of 0.996 and a low LOD of 3.6 μM. Furthermore, compared to undoped PeQDs, Eu3+ ion-doped PeQDs demonstrate strongly enhanced luminescence intensity and excellent photo-stability. This work expands the potential applications of lead-free PeQDs while simultaneously improving their luminescent properties. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Gd2Zr2O7 is one of the most promising new generation of ceramic materials for high temperature thermal barrier coatings. However, it still has great potential of improving thermal and mechanical properties and contributing tobetter thermal cycling performance of the coating. Doping rare earth elements in Gd2Zr2O7 is an effective method to enhance its thermal and mechanical properties. In this paper, the first principles is used to calculate the thermophysical properties of doped Gd2Zr2O7 with 16 rare earth elements, including modulus of elasticity, Debye temperature, minimum high-temperature thermal conductivity, high temperature thermal expansion coefficient, and fracture toughness, by which all doped Gd2Zr2O7 ceramics were ranked using the entropy method. The results show that doping with Pr, Sm, Yb, and Nd showed superior comprehensive performance. Specially, (Gd0.875Pr0.125)2Zr2O7 has the lowest Young's modulus of 244 MPa, Pugh ratio of 0.53, Debye temperature of 523.4 K, thermal conductivity of 1.27 W/(m·K), and the largest coefficient of thermal expansion of 9.19 × 10−6 K−1, and (Gd0.875Ho0.125)2Zr2O7 has the highest fracture toughness of 2.21 MPa·m1/2.

As a highly promising thermoelectric material in the mid‐temperature region, pristine GeTe shows deteriorated thermoelectric properties due to the low Seebeck coefficient and the intrinsic high thermal conductivity. Herein, it is discovered that the introduction of strongly correlated d, f electrons by alloying rare‐earth atoms at Ge sites will increase the band effective mass and promote band convergency, which can largely improve the electric transport property. Moreover, the heavy atoms (Pb, Bi) doping induces optical phonon softening and the avoided crossing between acoustic and optical phonon branches, decelerating both optical and acoustic phonon velocities. The modulated composition wave from the fluctuated multi‐component distribution introduces a complicated hierarchical structure including point defects and nanoprecipitates, which provides all‐scale scattering sources for heat‐carrying phonons and results in low lattice thermal conductivity. Consequently, a high zT of 2.4 at 800 K can be obtained in the Ge0.86Pb0.09Bi0.03Ce0.005Te sample due to the combination of strong correlation for d, f electrons and the full‐spectrum scattering for phonons. This work provides an effective strategy to increase the thermoelectric performance of IV–VI compounds by combining the modulated band structure and the softening phonon dispersion. [ABSTRACT FROM AUTHOR]

Over the years, metal oxides have been leveraged to create several intriguing novel antibacterial active materials such that while finding the ways and means to increase efficiency, rare earth elements are found to have often served as potential optical dopants such that an optimistic en route to achieve the same, branched Sm‐doped CuO nano‐lanceolates were synthesized employing a wet chemical approach. The samples were then annealed at three distinct temperatures, which were fixed to 300 °C, 400 °C, and 500 °C. The nano‐lanceolates have crystallized in the monoclinic phase, according to the XRD analysis. The SEM image of Sm‐doped CuO captured at a magnification of 2 μm reveals a branched morphology, with multiple nano‐lanceolates stacked in a stem. TEM image reveals that the width of a typical nano‐lanceolate attached to a stem and its tip are found to be 87 nm and 212 nm, respectively and the obtained EDS data validate that elements including Cu, Sm, and O are present in the doped sample. The UV‐visible spectra of the annealed samples indicate that the sample annealed at 300 °C (1.43 eV) has a larger band gap than the other samples. The sample that was annealed at 400 °C has endured defect emissions that are more intense than those of other samples, according to the obtained PL spectra. In addition to these fascinating findings, the samples annealed at 300 °C, 400 °C and 500 °C exhibit a zone of inhibition of 23 mm & 24 mm, 11 mm & 12 mm and 12 mm & 11 mm, respectively for the two tested bacterial strains which authenticate that the 300 °C annealed Sm‐doped CuO nano‐lanceolate deactivates the two pathogenic bacteria more effectively compared to the other samples. As a consequence, the Sm‐doped CuO nano‐lanceolates at 300 °C could potentially be an effective alternative for antibacterial materials, particularly in biomedical applications [ABSTRACT FROM AUTHOR]

In this study, original titanium dioxide (TiO2) and cerium (Ce)-doped TiO2 nanorod array photoanodes are prepared by hydrothermal method combined with high-temperature annealing, and their morphology, photoelectrochemical properties, and photocatalytic hydrogen production ability are systematically evaluated. X-ray diffraction (XRD) analysis shows that as the Ce content increases, the diffraction peak of the rutile phase (110) shifts towards lower angles, indicating the successful doping of different contents of Ce into the TiO2 lattice. Photoelectric performance test results show that Ce doping significantly improves the photocurrent density of TiO2, especially for the 0.54wt% Ce-doped TiO2 (denoted as CR5). The photocurrent density of CR5 reaches 1.98 mA/cm2 at a bias voltage of 1.23 V (relative to RHE), which is 2.6 times that of undoped TiO2 (denoted as R). Photoelectrochemical hydrolysis test results show that the hydrogen yield performance under full-spectrum testing conditions of Ce-doped TiO2 photoanodes is better than that of original TiO2 as well, which are 37.03 and 12.64 µmol·cm−2·h−1 for CR5 and R, respectively. These results indicate that Ce doping can effectively promote charge separation and improve hydrogen production efficiency by reducing resistance, accelerating charge transfer, and introducing new electronic energy levels. Our findings provide a new strategy for designing efficient photocatalysts with enhanced photoelectrochemical (PEC) water-splitting performance.

We present a study on the green synthesis of undoped and Er-doped ZnO compounds using Mangifera indica gum (MI). A set of tests were conducted to assess the structure of the material. The tests included X-ray diffraction, Raman, and Fourier-transform infrared spectroscopy. Optical properties were studied using diffuse reflectance and photoluminescence. Morphological and textural investigations were done using SEM images and N2 adsorption/desorption. Furthermore, photocatalytic tests were performed with methylene blue (MB), yellow eosin (EY), and the pharmaceutical drug ibuprofen (IBU) under UV irradiation. The study demonstrated that replacing the stabilizing agent with Mangifera indica gum is an effective method for obtaining ZnO nanoparticles. Additionally, the energy gap of the nanoparticles exhibits a slight reduction in value. Photoluminescence studies showed the presence of zinc vacancies and other defects in both samples. In the photocatalytic test, the sample containing Er3+ exhibited a degradation of 99.7% for methylene blue, 81.2% for yellow eosin, and 52.3% for ibuprofen over 120 min. In the presence of methyl alcohol, the degradation of MB and EY dyes is 16.7% and 55.7%, respectively. This suggests that hydroxyl radicals are responsible for the direct degradation of both dyes. In addition, after the second reuse, the degradation rate for MB was 94.08%, and for EY, it was 82.35%. For the third reuse, the degradation rate for MB was 97.15%, and for EY, it was 17%. These results indicate the significant potential of the new semiconductor in environmental remediation applications from an ecological synthesis. [ABSTRACT FROM AUTHOR]

Rear-earth doped advanced thermal barrier coatings (TBCs) have been developed by in-situ doping of Gd into YSZ matrix by atmospheric plasma spray coating of YSZ and Gd 2 O 3 (6 to 15 mol %) premixed powders. These modified TBCs are deposited over CoNiCrAlY bond coated Inconel 718 substrate. Diffusion of Gd or Gd3+ into YSZ matrix resulted in further stabilization of its tetragonal phase which is confirmed by detailed X-Ray diffraction analysis. Microstructure and chemical compositions of doped TBCs are examined by scanning electron microscopy and energy dispersive spectroscopy, respectively. Incorporation of Gd 2 O 3 resulted in relatively denser and smoother coating compared to pure YSZ coating for identical process parameters due to finer particle size and complete melting of Gd 2 O 3 powders. However, in-situ doped coatings are sinter resistant at elevated temperature unlike pure YSZ coating which aids in retention of porosities during high temperature exposure and provide better thermal performances. Modified TBCs showed higher hardness and Young's modulus, as revealed by micro and nano hardness measurements. High temperature isothermal oxidation studies carried out between 1173 K and 1273 K allowed evaluation of the efficacy of modified TBCs for oxidation resistance and related kinetics. The results show that modified TBCs provide better oxidation resistance compared to pure YSZ coating. Erosion tests of TBCs both at ambient and elevated temperature (773 K) showed that modified coatings are more resistant to erosion compared to YSZ coating. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian Polytechnic University is the property of Journal of Dalian Polytechnic University Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ultraviolet (UV) excited down‐shifting (DS) double perovskites with broad emission have potential applications in anti‐counterfeiting. However, discovering new materials and achieving multimode luminescence present significant challenges. In this work, a novel double perovskite, Cs2NaGdCl6 is synthesized, with sky‐blue self‐trapped exciton (STE) emission under UV excitation using a solvothermal method. By incorporating Er3+ ions into Cs2NaGdCl6, green DS and green up‐conversion (UC) luminescence are achieved under UV and near‐infrared (NIR) excitation. The addition of the sensitizer Yb3+ ion led to a significant enhancement of 21.5‐fold in DS red luminescence and 7.5‐fold in UC green luminescence. The color of both DS and UC luminescence in Cs2NaGdCl6:Yb3+, Er3+ is further adjusted from green‐dominated to red‐dominated, due to the cross‐relaxation process between Er3+ and Yb3+, Er3+ and Er3+, respectively. The combination of UC and DS luminescence, along with the ability to modulate emission color in rare‐earth‐based materials, opens new possibilities for high security anti‐counterfeiting applications. [ABSTRACT FROM AUTHOR]

Metal halide perovskites (MHPs) have shown great application prospects in the field of optoelectronics owing to their superior optical and optoelectronic properties. Bandgap engineering and impurity doping are effective ways to achieve regulation of luminous properties in the visible light region. However, realizing efficient deep red and wide‐range tunable near‐infrared (NIR) emission remains a challenge. Here, a series of rare earth (RE3+) ions (RE = Nd, Dy, Ho, Er, Tm, Yb) doped Cs4Cd1−xMnxSb2Cl12 (0 ≤ x ≤ 1) quadruple perovskites are designed. An efficient tunable luminescence from red to NIR light is achieved based on the energy transfer (ET) from Mn2+ to RE3+ by building the Mn2+ energy bridge, which covers the NIR‐I (650–900 nm) and NIR‐II (900–1700 nm) regions. Moreover, the ET efficiency is availably influenced by the doping concentration of Mn2+. Interestingly, the energy bridge from Mn2+ to RE3+ is cut off because of the increased bandgap when Bi3+ is introduced into the RE3+‐doped Cs4Cd0.4Mn0.6Sb2−yBiyCl12 (0 ≤ y ≤ 2) lattice. Through bandgap engineering, the ET from Mn2+ to RE3+ resembles an "optical energy shutter" which quenches the NIR emission of RE3+ owing to the mismatched energy level but enhances the emission of Mn2+. [ABSTRACT FROM AUTHOR]

Based on the first principle calculation method of density functional theory (DFT), the electronic structure and optical properties of intrinsic GaSb and GaSb doped with rare earth elements Sc and Tm were studied. The results of the calculations show that the Sc and Tm doped GaSb materials are still direct band gap P-type semiconductors. The Sc-doped GaSb material induces a shallow energy level defect state in the conduction band and the band gap becomes narrower. Tm doping induces deep energy level defect states in the conduction band and the band gap becomes wider. Sc and Tm doping reduces the energy loss and enhances the absorption of GaSb photons in the mid-infrared band, with Sc doping being more effective, with an absorption peak value of 1.9 × 105 cm-1 at 5.3 μm (0.233 eV), and the light absorption coefficient still reaches 1 × 105 cm-1 until the wavelength is 13.3 μm (0.093 eV). The results provide a theoretical reference for expanding the application of GaSb-based semiconductor materials in infrared detectors and infrared semiconductor lasers. [ABSTRACT FROM AUTHOR]

Tb3Scx Al5-xO12 (TSAG) crystal is a magneto optical crystal material with excellent performance. Solving the cracking problem during the growth of large-sized TSAG crystal is of great significance for its application in high-power magneto-optical isolators. The segregation law of Dy and Lu during the crystal growth process with Czochralski method was investigated, and the effect of Dy and Lu doping on the crystal properties TSAG were also clarified. The results indicate that Dy and Lu doping are helpful to solve the cracking problem of large-sized TSAG crystal. The obtained TSAG crystals have good internal quality, and the resulting extinction ratios are all greater than 33 dB. Lu doping improves the Verde constant of TSAG crystals, while Dy doping has no significant effect on the Verde constant of TSAG crystals. The magneto-optical properties of Dy and Lu co-doped TSAG crystals are basically similar to those of TSAG, and the prepared crystals meet the requirements for high-power laser isolators. [ABSTRACT FROM AUTHOR]

ABO 3 type perovskite oxides have been widely studied due to their unique structure and special electromagnetic properties. CaMnO 3 is well known for its excellent thermoelectric performance and temperature stability. In this paper, Ca 1-x Gd x MnO 3 (x = 0, 0.1, 0.2, 0.3, 0.4) perovskites were comprehensively studied by first-principles calculations and experimental characterizations on their crystal structure and electromagnetic properties to finally elaborate the microwave absorption mechanism. It is found that Gd doping significantly enhances the dielectric polarization effects, resulting in better electromagnetic wave absorption performance than undoped CaMnO 3. Especially for CG2MO perovskite, its reflection loss and bandwidth below −10 dB at 2–18 GHz reaches −31.9 dB and 3.3 GHz approximately, exhibiting excellent microwave absorption property. Moreover, the microwave absorption mechanism of CGMO perovskites involves various modes of conductive loss, resonance loss, multiple reflection and scattering as well as the polarization phenomenon including interfacial polarization, dipole polarization and defect polarization. Among them, polarization effects and conductive loss contributes the most to the microwave absorption performance. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this paper, rare earth ion Nd doped LiLuF4 (LLF) microcrystals were prepared by hydrothermal method. The phase analysis, morphology analysis of the crystals were performed and near infrared optical properties were studied. LLF crystals belong to the scheelite structure of tetragonal system and the space group is I41/a. The LLF microcrystalline materials prepared by hydrothermal method have good crystallinity and the particle size is about 20 μm. The oxygen content of the optimized Nd∶LLF sample is 0. 001 4% (mass fraction). Under excitation of 792 nm wavelength, the main fluorescence emission peak of 3% (mole fraction) Nd-doped LiLuF4 microcrystal is located at 1 047 nm, which belongs to near infrared bands, and its fluorescence lifetime is about 0. 275 1 ms. Furthermore, Nd∶LLF crystal was grown by the Czochralski method and its laser performance was evaluated. The emission cross section of Nd∶LLF crystal at 1 053 nm is 8. 13 ×10 -20 cm2. The laser performance test and analysis show that under the excitation power of 1. 2 W, Nd∶LLF crystal obtains a near-infrared laser output of 0. 123 W at 1 053 nm. [ABSTRACT FROM AUTHOR]

ZnO quantum dots with different Eu-doped concentrations (0, 0.05, 0.10 and 0.15 mol/L) were prepared based on hydrothermal and spin-coating methods. Photoanode films were prepared on the basis of Eu-doped ZnO quantum dots, and quantum dot sensitized solar cells were prepared as photoanodes. The effects of Eu-doped concentration on the morphology, crystal structure, spectral properties and photoelectric properties of ZnO films were studied. The results showed that Eu-doped ZnO nanorods prepared by hydrothermal method belong to hexagonal wurtzite structure. Eu-doped ZnO nanorods did not produce new products, but refined the diameter of ZnO nanorod array, with a diameter distribution of 45～60 nm and a height of about 1.2 μm. The orientation and uniformity of ZnO nanorods had been improved. Eu doping reduced the band gap width of ZnO, reduced the photoluminescence intensity of ZnO, and improved the separation ability of electron pairs. When the concentration of Eu doping was 0.10 mol/L, the minimum band gap width of ZnO was 3.09, and the photoluminescence intensity was the lowest. The doping of Eu improved the photoelectric performance of the quantum dot sensitized solar cell assembled based on ZnO as the counter electrode. When the concentration of Eu doping was 0.10 mol/L, the photoelectric conversion efficiency could reach 4.03%, the charge transfer impedance of the counter electrode was 1.38 Ω, the exchange current density of the counter electrode was 9.92 mA/cm~2, and the photoelectric performance was the best. [ABSTRACT FROM AUTHOR]

A series of Tb3+-doped, Ce3+,Tb3+-co-doped and Ce3+,Tb3+,Mn2+-tri-doped CaScBO 4 (CSB) ceramic phosphors were prepared by solid-state reaction. X-ray diffraction (XRD) was taken to confirm the phase purity of all as-prepared phosphors powder. Steady-state and transient-state fluorescence spectra were applied to evaluate the luminescence properties of the phosphors. The results indicated that significant enhancement on Tb3+ luminescence was successfully realized by the Ce3+-induced resonance energy transfer and confirmed that the energy transfer from Ce3+ to Tb3+ was governed by an electronic dipole-dipole interaction. Compared to the CSB:Tb3+ phosphors whose optimal excitation located at 378 nm, the occurrence of Ce3+-Tb3+ energy transfer not only allowed the optimal excitation to peak at around 390 nm but also gifted the CSB:Ce3+,Tb3+ phosphors color tunability from blue, cyan to green. Then, two different designs of white light by the introduction of Mn2+ luminescence were performed. One was the combination of CSB:Ce3+,Tb3+ and CSB:Ce3+,Mn2+ phosphors, based on the co-excitation of the above two phosphors at the same wavelength. Another was the direct use of the tri-doped CSB:Ce3+,Tb3+,Mn2+ phosphors. Both designs succeeded in the generation of white light emission. The performance of these two designs in real devices were also studied. The direct use of the tri-doped CSB:Ce3+,Tb3+,Mn2+ phosphor in white light-emitting diode (WLED) device can produce white light with a color rendering index (CRI) up to 85.3 while the use of the CSB:Ce3+,Tb3+ and CSB:Ce3+,Mn2+ phosphors combination can just produce a value of 76.6 in CRI. [ABSTRACT FROM AUTHOR]

Rare earth (RE) doped cobalt ferrite (CFO) nanoparticles were synthesized by sol-gel auto combustion method, and the effect mechanism of RE3+ replacing Co2+ or Fe3+ on CFO was studied for the first time. The different roles of RE added to CFO in changing cation distribution and further affecting structure and magnetism properties due to different substitution positions were focused. The crystal structure formation and crystallite size were investigated by XRD and the results showed that the replacement of Co2+ ions by RE3+ ions was more likely to lead to larger lattice distortion and smaller grains compared with the replacement of Fe3+ ions by RE3+ ions. The SEM and TEM results showed that RE3+ doping not only reduced the grain size, but also made the grain distribution more uniform. The FTIR analysis confirmed that the synthesized material belonged to the spinel structure, and the results also showed that the space shrinkage of tetrahedron (A-sites) was more likely to be caused by the substitution of RE3+ for Co2+ ions. Room temperature magnetization measurements showed that the saturation magnetization of CFO decreased with the substitution of RE3+ ions, and the change of coercivity was related to the substitution position and type of RE3+ ions. The coercivity increased significantly with the substitution of Co2+ ions by RE3+, reaching a maximum of 2423 Oe (Co 0.8 Gd 0.2 Fe 2 O 4), and decreased with the substitution of Fe3+ ions by RE3+. Due to the difference of grain size and RE3+ doping, the magnetic domain presents single or multi domain structure. It can be concluded that the substitution of RE3+ ions for different ions will cause cation rearrangement, and then the cation rearrangement and grain size together lead to a large change in the coercivity of CFO, which puts forward a new direction for the subsequent improvement of the coercivity of materials. [Display omitted] [ABSTRACT FROM AUTHOR]

In recent years, rare-earth-doped up-conversion luminescent materials have received increasing attention in solar cells, industrial lighting, and medical fields. The current research is mainly to find new and efficient rare-earth up-conversion luminescent materials. For the study of luminescent materials, the choice of matrix is particularly important. Molybdate stands out from many matrixes due to its stable physical and chemical properties and low phonon energy. In this paper, molybdate is selected as the matrix material doped with rare earth ions. Tm and Yb ion-doped NaGd (MoO4)2 samples are prepared by hydrothermal method, and the change of the luminescence characteristics of NaGd (MoO4)2 phosphor is explored by changing the ion doping concentration. Through the analysis of its spectrum, it is found that under 980 nm laser irradiation, NaGd (MO4)2: Yb3+/Tm3+ has a blue emission peak at 477 nm and a red emission peak at 648 nm. When the doping mole fraction of fixed Yb3+ is 6% and the doping mole fraction of Tm3+ is changed to 0, 0. 5%, 1% and 2% respectively, it is found that with the increase of the doping mole fraction of Tm3+, the intensity of the emission peak at 477 nm first increases and then decreases. When the doping mole fraction of Tm3+ is 0. 5%, the luminous intensity of molybdate phosphor first increases and then decreases to the maximum. It has broad prospects in the application of multi-color lighting and light source devices. [ABSTRACT FROM AUTHOR]

We present a study on the green synthesis of undoped and Er-doped ZnO compounds using Mangifera indica gum (MI). A set of tests were conducted to assess the structure of the material. The tests included X-ray diffraction, Raman, and Fourier-transform infrared spectroscopy. Optical properties were studied using diffuse reflectance and photoluminescence. Morphological and textural investigations were done using SEM images and N2 adsorption/desorption. Furthermore, photocatalytic tests were performed with methylene blue (MB), yellow eosin (EY), and the pharmaceutical drug ibuprofen (IBU) under UV irradiation. The study demonstrated that replacing the stabilizing agent with Mangifera indica gum is an effective method for obtaining ZnO nanoparticles. Additionally, the energy gap of the nanoparticles exhibits a slight reduction in value. Photoluminescence studies showed the presence of zinc vacancies and other defects in both samples. In the photocatalytic test, the sample containing Er3+ exhibited a degradation of 99.7% for methylene blue, 81.2% for yellow eosin, and 52.3% for ibuprofen over 120 min. In the presence of methyl alcohol, the degradation of MB and EY dyes is 16.7% and 55.7%, respectively. This suggests that hydroxyl radicals are responsible for the direct degradation of both dyes. In addition, after the second reuse, the degradation rate for MB was 94.08%, and for EY, it was 82.35%. For the third reuse, the degradation rate for MB was 97.15%, and for EY, it was 17%. These results indicate the significant potential of the new semiconductor in environmental remediation applications from an ecological synthesis.

Rare earth element Tb doped DyBaCo4O7+δ nano-powder was synthesized by sol-gel process.The effect of Tb doping with different concentration on the morphology, crystal structure and oxygen adsorption-desorption properties of DyBaCo4O7+δnano-powder was studied.Dy1-xTbxBaCo4O7+δ nanopowder is still hexagonal close packed crystal structure at low Tb doping concentration. Tb doping has little effect on the morphology of Dy1-xTbxBaCo4O7+δnanopowder. From room temperature to 1 000 ℃, DyBaCo4O7+δnanopowder and Dy1-xTbxBaCo4O7+δnanopowders showed two times of oxygen adsorption and desorption.Compared with the oxygen adsorption performance of DyBaCo4O7+δnanopowder, the oxygen adsorption capacity of Tb doped DyBaCo4O7+δ nanopowder is obviously higher than that of undoped DyBaCo4O7+δ. The oxygen adsorption capacity of DyBaCo4O7+δis 1.4%, while the oxygen adsorption capacity of Dy1-xTbxBaCo4O7+δis 4.9%. DyBaCo4O7+δnanopowders and Dy1-xTbxBaCo4O7+δnanopowders showed good oxygen adsorption/desorption behavior during N2/O2 gas switching. The improvement of the oxygen adsorption/desorption performance of DyBaCo4O7+δcan be attributed to the improvement of the spacing of DyBaCo4O7+δand the increase of the oxygen storage space of DyBaCo4O7+δ. [ABSTRACT FROM AUTHOR]

Tuning morphology and doping additional rare earth (RE) cations are potential techniques to promote the photocatalytic performance of ceria (CeO2), evaluating the collaborative effects of morphology and RE dopants is significant for producing high active ceria-based catalysts. So in this work, cubic, polyhedral and rod-like nanoceria doped with 10 mol % La (lanthanum), Y (yttrium), or Sm (samarium) were synthesized by a facile template-free hydrothermal method. Phases, morphologies, oxygen vacancies (OVs) concentration, energy band structure, photo-carriers separation/recombination, and photodegradation ratio toward methylene blue (MB) dye of as prepared ceria were studied. Results show that doped CeO2 maintains a similar morphology structure with un-doped sample and the band gap narrows slightly. Y-doped nanoceria, with an improved separation and a reduced recombination of photo-excited electrons (e−) and holes (h+), owns a higher MB photodegradation ratio than that of samples doping with La or Sm, which is measured as 79.04, 84.43, and 85.59% for Y-doped cubic, polyhedral, and rod-like CeO2. The collaborative influence of morphology tuning and RE (La, Y, and Sm) doping on photocatalytic performance of nanoceria includes the effects of doped elements and the formation of OVs. The elevation of OVs concentration as well as the separation efficiency of photo-generated e−/h+ are suggested to further enhance the photocatalytic performance of ceria. [ABSTRACT FROM AUTHOR]

Bi0.5Na0.5TiO3 (BNT)-based ceramics are one of the most promising lead-free ferroelectrics due to their high strain property. Compared to other chemical modifications, rare earth ions doping provides significant possibility to optimize the strain property of BNT-based ceramics. In this work, the effects of rare earth ions on phase structure, microstructure, and strain & electrostrictive properties of lead-free BNT-based ceramics were systematically investigated. Rare earth ions (i.e., La3+, Sm3+, Yb3+, Dy3+, and Nd3+) were selected as the doping ions. Introducing moderate La3+ ions can drive the ferroelectric state of BNT-based ceramics to nonergodic relaxor state or ergodic relaxor state. The enhanced strain response of ∼0.40–0.42% and high converse piezoelectric coefficient of ∼600–630 pm/V can be achieved under 60–70 kV/cm for La3+-doped ceramic with nonergodic relaxor state. Besides, the giant electrostrictive coefficient Q33 of ∼0.047 m4/C2 can be obtained for La3+-doped ceramic with ergodic relaxor state. Other rare earth ions also present the promotion effect on strain enhancement for BNT-based ceramics. This study affords a significant guidance to optimize strain and electrostrictive properties of BNT-based ceramics via rare earth ions doping.

SiO 2 –B 2 O 3 -GdF 3 -CaO-Bi 2 O 3 doped glasses containing Er3+/Yb3+ ions at varying concentrations were successfully synthesized using a high-temperature melting method. The glass samples' physicochemical properties and amorphous structure were characterized through density, XRD, XPS, FT-IR, and Raman analyses. Thermal expansion coefficient testing indicated good thermal stability of the glass system. Increasing the Yb3+ doping concentration enhanced near-infrared luminescence at 1.53 μm, with maximum luminescence intensity at approximately 3.2 mol% doping concentration. The energy transfer mechanism of Er3+/Yb3+ doped SiO 2 –B 2 O 3 -GdF 3 -CaO-Bi 2 O 3 glass was elucidated through fluorescence spectrum analysis, revealing J-O parameters Ω 2 = 11.2 × 10−20 cm2, Ω 4 = 8.9 × 10−20 cm2, and Ω 6 = 9.59 × 10−20 cm2. Calculations for absorption cross-section, cross-section of emission, and gain curve additionally reinforced the glass's capability for laser uses. • SiO 2 –B 2 O 3 -GdF 3 -CaO-Bi 2 O 3 doped glasses containing Er3+/Yb3+ ions were synthesized using a high temperature melting method. • The doping of GdF 3 introduces F− ions into the glass system destroys the network structure of silicate glass, and further reduces the phonon energy of the glass. • The glass sample with 3.2 mol Yb3+ ions exhibits peak fluorescence emission intensity under 980 nm pump with an emission cross section of 2.79 × 10−21 cm2. [ABSTRACT FROM AUTHOR]

Y 2 O 3 coatings are widely applied in semiconductor etching machines to protect the inner walls of aluminum alloys. This study reports the preparation of yttria-based coatings on aluminum alloy substrates using atmospheric laminar plasma spraying (ALPS) methods. In this study, four yttria-based coatings were designed and tested for their thermal performance, plasma etching resistance, and resistance to laser ablation. The rare-earth-zirconia (RE-ZrO 2) doped Y 2 O 3 coating exhibited the best thermal insulation performance, with a thermal conductivity of approximately 0.6 W m−1 k−1 at 600 °C. Plasma etching experiments demonstrated that more rare-earth fluorides were generated on the surface of the RE-ZrO 2 doped Y 2 O 3 coating, which weakened the plasma energy. Finally, the lowest etching rate was achieved. Laser ablation experiments demonstrated that the depth of the ablation pit on the surface of the RE-ZrO 2 doped Y 2 O 3 coating was shallow, indicating good laser ablation resistance. These results indicate that rare-earth-doped yttria-based coatings provide excellent corrosion protection against plasma etching and laser ablation. • Four coatings were prepared using atmospheric laminar plasma spraying. These coatings include Y 2 O 3 , 70 mol%Y 2 O 3 –30 mol%RE-ZrO 2 , 70 mol% Y 2 O 3 –30 mol%ZrO 2 , and 60 mol%Y 2 O 3 –25 mol%ZrO 2 –15 mol%Al 2 O 3. • The RE-ZrO 2 doped Y 2 O 3 coating exhibited the best thermal insulation performance. • The RE-ZrO 2 doped Y 2 O 3 coating had the best resistance to plasma etching. During plasma etching, the addition of rare earth elements to the coating surface resulted in the formation of high sublimation point fluorine-containing compounds that inhibited the etching process. • The RE-ZrO 2 doped Y 2 O 3 coating also exhibited good resistance to laser ablation. [ABSTRACT FROM AUTHOR]

The numerous benefits like smaller size, easy handling, quicker readouts and cost effectiveness render TLDs as prominent radiation dose measuring instruments. Zinc Oxide (ZnO) is well recognized among these TLD materials due to its remarkable post exposure glow properties. Moreover, along with reasonable TL properties it inherently shows good mechanical and chemical stability, non-toxic and non-hygroscopic nature. However, in comparison to its contemporaries it lacks in sensitivity when exposed to low radiation doses and exhibits moderate fading effects. These draw backs stem from ZnO electronic nature i.e. availability of low number of radiation responding electrons along with trapping centers which can retain these electrons and are responsible for thermal assisted glow curve. One of the solutions is doping it with high atomic number metallic ions. Transition metals (TM) and rare earth (RE) elements doped ZnO materials show promising results i.e. doped ZnO shows improved TL response i.e. more linearity, better stability and less fading. As TM and RE doped ZnO appears to be promising TLD materials, this review provides an overview of research on TL characteristics of TM and RE doped ZnO materials. • ZnO TLD sensitivity is tunable in terms of transition and rare earth doping. • Stable TLD performance in high doses is possible employing doped ZnO. • Future passive dosimetry is possible employing cost-effective TM and RE doped ZnO. • The avenue of research for deeper understanding and linearity of response in all dose limits is still open for doped ZnO TLD. [ABSTRACT FROM AUTHOR]

• A novel red emitting NaLa (1-x) MgTeO 6 :xSm3+ phosphors were synthesized. • Under n-UV excitation, the synthesized phosphors exhibit warm red emission with high color purity. • The emission range of synthesized phosphor is sensitive to human eye. • The phosphor incorporated security ink shows bright luminescence under n-UV light and invisible under day light. • The phosphor found applications in WLEDs and security ink applications. Recently, red phosphors are extensively developed to find applications in phosphor converted white LEDs (pc-WLEDs) and anti-counterfeiting. In this work, samarium doped sodium lanthanum magnesium tellurate (NaLaMgTeO 6 :Sm3+) red emitting phosphors have been synthesized for the first time via solid state reaction method. Rietveld refinement of XRD pattern reveals monoclinic crystal structure of NaLaMgTeO 6. Under 404 nm (6H 5/2 → 4F 7/2) n-UV excitation, NLMT:Sm3+ phosphor shows red emission at 643 nm (4 5/2 → 6 9/2) with color purity 100 % and the obtained CCT value corresponds to warm light source. Temperature-dependent PL analysis of NLMT:Sm3+ exhibits good thermal stability. The anti-counterfeiting security ink was developed using optimized phosphor and the information was encrypted on different surfaces using the prepared security ink. The encrypted data was decoded only by n-UV light. The aforementioned results revealed that NLMT:Sm3+ is a highly effective phosphor as a red component for pc-WLEDs and luminescent dye for anti-counterfeiting applications. [Display omitted] [ABSTRACT FROM AUTHOR]

CdS is a potential candidate for material in optoelectronic applications. The magnetic, electronic and optical properties of Ag-doped and Co -codoped CdS were calculated using full potential linear augmented plane wave (FP-LAPW) based on popular density - functional theory (DFT). The band gap and density of states for Ag -doped and Cocodoped CdS have been determined by using Tran Blaha modified Becke-Johnson (TBmBJ) potential. The optical and electronic properties of Ag-doped and Co-codoped CdS such as absorption coefficient, energy loss function, reflectivity, refractive index, electrical conductivity and extinction coefficient are presented. The results indicate that the magnetic and electro-optical properties are improved by this doping. [ABSTRACT FROM AUTHOR]

Double perovskites, as a star material, are becoming a significant research domain due to their flexible structure, variable formulae, unique properties and wide applications. Trimming the materials into nano regime and introducing rare-earth integration would improve their properties and broaden their applications. The main purpose of this work lies in the comparison of luminescence properties of double perovskite nanophosphors La2MgTiO6 (LMT), Gd2MgTiO6 (GMT) and Y2MgTiO6 (YMT). A detailed list of numerous excitation and corresponding emission wave lengths are discussed. Various synthesis methods adopted for the fusion of these materials, which are reported till this date, are also considered. This study shall assist the scientific community to identify the suitable host for luminescent applications in the field of lighting, displays, illumination, biological imaging, biological sensing etc. [ABSTRACT FROM AUTHOR]

A thin film of cobalt ferrite (CoFe2O4) was successfully deposited through nebulizer assisted spray pyrolysis technique. Composition of elements in the thin film plays an important role in determining its magnetic properties. Significant changes in the structural and magnetic properties can be observed in the CoFe2O4 thin films when doped with rare earth elements making it suitable for the applications in magnetic and related devices. Undoped and neodymium-doped CoFe2O4 thin films were prepared through nebulizer assisted spray pyrolysis (NSP) method on bare glass substrates by changing the percentage of Nd doping level from 0 to 5% atomic weight. Standard characterization techniques were used to analyze the deposited films to reveal the effect of doping. Crystallite size is estimated from x-ray diffraction spectra, and is observed to be of the order of 14 nm. The size of the crystallites in the film seems to decrease with the increase in doping concentration. The optical band gap value shows an increase and gets shifted from 1.82 to 1.95 eV on increasing the concentration of Nd doping. The saturation magnetization of the prepared CoFe2O4 films obtained at 0% and 5% show a strong dependence on the Nd doping concentration. This study shows that the Nd-doped CoFe2O4 films can compete with the existing materials for magnetic device applications. [ABSTRACT FROM AUTHOR]

In preparing MoS2-based coatings by magnetron sputtering, the working pressure of the vacuum chamber directly affects the number and kinetic energy of sputtering particles, which causes a difference in coatings structure and performance. In this paper, MoS2 composite coatings with Ce and Ti binary doping were prepared by unbalanced magnetron sputtering technology, and the variation of composition, structure, and tribological properties of Ce-Ti/MoS2 coatings under different working pressures was studied. The results demonstrated that Ce and Ti doping improves pure MoS2 coatings. The Ce-Ti/MoS2 coatings reached the hardness of 9.02 GPa and the friction coefficient of 0.065 when working pressure was at 0.6 Pa. It was also observed that the deposition efficiency and wear rate reached the optimal value at 0.9 Pa. With the increase of working pressure, the columnar structure of the coating was coarse due to the change of kinetic energy and quantity of particles in the chamber. The intensity of the MoS2 (002) diffraction peak decreased, which eventually led to a poor lubrication effect and aggravated wear. This study provides technical guidance for preparing metal-doped MoS2 composite coatings with excellent mechanical and tribological properties. [ABSTRACT FROM AUTHOR]

Yb3+/Er3+/Tm3+- and Yb3+/Er3+/Tm3+/Ho3+-doped α -NiMoO4 nanoparticles were synthesized using a microwave hydrothermal method and studied for white-light emission under 980 nm laser diode excitation. White upconversion (UC) light was successfully obtained with the appropriate control of blue, green, and red emissions by successfully tuning the Er3+ and Ho3+ concentrations in Yb3+/Er3+/Tm3+- and Yb3+/Er3+/Tm3+/Ho3+-doped α -NiMoO4, respectively. In addition, the white color emission was shown by the CIE chromaticity coordinates of samples. The energy transfer mechanisms are explained in detail based on the emission spectra and pump power density-dependent UC luminescence intensity in rare earth (Yb3+/Er3+/Tm3+ and Yb3+/Er3+/Tm3+/Ho3+)-doped α -NiMoO4 nanoparticles. The results indicate that Yb3+/Er3+/Tm3+- and Yb3+/Er3+/Tm3+/Ho3+-doped α -NiMoO4 nanoparticles can be good candidates for white-light devices. [ABSTRACT FROM AUTHOR]

Rare earth ion doped upconversion luminescent materials have been widely used in lighting and solar cell industries in recent years. NaGd（MO4）2 phosphors doped with Ho3+/Yb3+ were prepared by hydrothermal method. NaGdMO4）2 phosphors were characterized by XRD, SEM and spectral analysis. The effect of Ho3+/Yb3+ doping on the luminescence properties of molybdate phosphors was studied. The analysis of morphology and structure shows that the NaGdMO4）2 phosphors doped with Ho3+/Yb3+ have pure tetragonal phase structure, and the particle size is about 0.4～0.9 μm. The doping of Ho3+/Yb3+ makes the cell parameters of NaGdMO4）2 phosphor smaller. The spectral analysis shows that the green light at 546 nm in NaGdMO4）2 phosphor is the photons released from the Ho3+ transition from the ~5F4 energy level back to the ~5I8 energy level, and the red light at 659 nm is the photons released from the ~5F4 energy level back to the ~5I8 energy level. With the increase of Ho3+ doping content, the red emission intensity at 659 nm increases. When n(Ho3+)∶n(Yb3+)=2.0∶5.0, the red emission peak intensity of NaGdMO4）2 phosphor is the highest, and when the doping ratio of Ho3+ increases, the CIE color coordinates of the samples gradually move from the green region to the red region. The analysis of the upconversion transition mechanism of sample shows that the blue light of 546 nm and the red light of 659 nm of Ho3+/Yb3+ doped NaGdMO4）2 phosphor are two-photon processes. [ABSTRACT FROM AUTHOR]

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Dy3+, Nd3+, Sm3+ doped Y 2 O 3 nanophosphors were produced with high homogeneity at low sintering temperature using the sol-gel method. To compare the structural and optical changes of different rare-earth ions included in the crystal lattice, the dopant ratio was chosen as constant 2 mol%. In the light of X-ray diffraction (XRD) analysis, the unit cell volume and average crystallite size of the doped nanophosphors and their pure Y 2 O 3 sintered under the same heat treatment regime were calculated and compared. Scanning electron microscopy (SEM) techniques were used to describe their structures and morphologies; an average particle size histogram of nanostructures was generated. The Radioluminescence (RL) spectra of Y 2 O 3 :Ln3+ (Ln: Dy, Nd, Sm) nanophosphors were presented for the first time. Splittings were seen in detail in the emission spectra given the 200–1100 nm range. For Dy3+4F 9/2 → 6H 13/2 , for Nd3+; in the visible region 4H 11/2 -4I 9/2 in the NIR region 4F 3/2 -4I 9/2 , for Sm3+; in the visible region 4G 5/2 -6H 7/2 in the NIR region 4G 5/2 -6F 5/2 transitions were determined to have the most vigorous emission. It was observed that the optical band gap calculated from the absorption spectrum of Y 2 O 3 was 4.97 eV; this value changed the most with Dy contribution and decreased to 4.77 eV. The thermoluminescence (TL) behaviors of nanophosphors were compared under both UV and X-ray excitation. The kinetic parameters were calculated by applying computerized glow curve deconvolution (CGDC), and various heating rate (VHR) methods to the glow curves obtained UV excitation. The obtained E (eV) values correlated with each other are highly compatible. [ABSTRACT FROM AUTHOR]

ZnO nano- and microstructures co-doped with Eu and Li with different nominal concentrations of Li were grown using a solid vapor method. Different morphologies were obtained depending on the initial Li content in the precursors, varying from hexagonal rods which grow on the pellet when no Li is added to ribbons to sword-like structures growing onto the alumina boat as the Li amount increases. The changes in the energy of the crystallographic planes leading to variations in the growth directions were responsible for these morphological differences, as Electron Backscattered Diffraction analysis shows. The crystalline quality of the structures was investigated by X-ray diffraction and Raman spectroscopy, showing that all the structures grow in the ZnO wurtzite phase. The luminescence properties were also studied by means of both Cathodoluminescence (CL) and Photoluminescence (PL). Although the typical ZnO luminescence bands centered at 3.2 and 2.4 eV could be observed in all cases, variations in their relative intensity and small shifts in the peak position were found in the different samples. Furthermore, emissions related to intrashell transitions of Eu3+ ion were clearly visible. The good characteristics of the luminescent emissions and the high refraction index open the door to the fabrication of optical resonant cavities that allow the integration in optoelectronic devices. To study the optical cavity behavior of the grown structures, µ-PL investigations were performed. We demonstrated that the structures not only act as waveguides but also that Fabry–Perot optical resonant modes are established inside. Quality factors around 1000 in the UV region were obtained, which indicates the possibility of using these structures in photonics applications. [ABSTRACT FROM AUTHOR]

Tungsten oxide is widely used in the photolysis of water for hydrogen production, photocatalysis, photoelectric conversion, and electrochromism. Eu3+ doped tungsten trioxide nanoparticles were prepared by hydrothermal method with the addition of sodium tungstate (NaWO4 · 2H2O). Two different samples were obtained at the temperature set at 160 and 180°C. The third sample obtained from ammonium paratungstate ((NH4)10H2(W2O7)6) was used at the temperature of 160°C. The samples' morphology, structure, and optical performance were then observed and analyzed. The results show that a rod-like structure of WO3 : Eu3+ nanoparticle with a monoclinic crystal system can be successfully generated using sodium tungstate. A spherical structure of WO3 : Eu3+ nanoparticle with a triclinic crystal system was prepared using ammonium paratungstate. The finished sample with ammonium paratungstate at a reaction temperature of 160°C has the smallest grain average size of 45.98 nm and Eu3+ ions successfully doped. Under the excitation of different wavelengths, the three samples demonstrate pronounced emission peaks at around 615 nm, corresponding to the 5D0 → 7F2 electronic transition of Eu3+. Using ammonium paratungstate as the tungsten source, the prepared WO3 : Eu3+ nanoparticle at 160°C has the highest luminous intensity. The luminescence intensity of the prepared WO3 : Eu3+ nanoparticle from ammonium paratungstate as a tungsten source is higher than the other two samples obtained from sodium tungstate as a tungsten source at two temperatures. However, the three samples with excitation wavelength λ = 254 nm were monitored at the wavelength of 615 nm. All three samples exhibited the most substantial excitation peaks at about 508 nm, which belonged to the electron transition in 4f of Eu3+. [ABSTRACT FROM AUTHOR]