Doped Yttrium Research Articles

Exploring the Influence of Yttrium on the Structural, Physical, and Optical Properties of Sol-Gel Synthesized Silicophosphate Glasses for Photonics Applications

Yttrium-incorporated silicophosphate glasses hold significant appeal in key sectors such as photonics, optoelectronics, lasers, biomedical applications, and light-emitting diodes (LEDs). In this study, the sol-gel method has been used to prepare the pure and yttrium-doped silicophosphate glasses. The aim of this study is to discover the effect of yttrium doping on the structural, physical, and optical properties of silicophosphate glasses. Various techniques such as X-ray diffraction (XRD), FTIR spectroscopy, and UV-visible analysis have been employed to examine the structural and optical properties of the prepared samples. The XRD analysis confirmed that all the prepared samples exhibited an amorphous nature. Optical measurements conducted indicated that the incorporation of trivalent yttrium ions led to an increase in the refractive index of the prepared samples. Furthermore, a decrease in the energy band-gap values of the samples was observed. The FTIR spectral analysis unveiled the presence of diverse vibration modes in the synthesized samples. These encompassed symmetrical and asymmetrical stretching vibrations of P-O-P linkages, bending vibrations of P-O in PO4 groups, elongation and flexure vibrations of OH groups, and water absorption vibrations of P-O-H in the glasses. The acquired spectra robustly substantiate the function of yttrium oxide as a network modifier within the silicophosphate glass system. The theoretical values of optical basicity (Λth) demonstrated an increase from 0.465 to 0.472, while the values of the interaction parameter (A) exhibited a decrease from 0.218 Å−3 to 0.215 Å−3. Silicophosphate glasses doped with trivalent yttrium ions exhibit significant potential as materials for optoelectronic devices and optical filter systems.

Effect of yttrium doping on the properties of Nickel-Iron multiphase heterostructures at high current conditions

Transition metal selenides hold great promise for producing clean hydrogen energy from water electrolysis, but it is not clear how transition metal elements can improve the stability of catalyst performance at high current levels. This work presents the use of nickel foam (NF) as a hydrothermal selenium substrate for yttria-doped multiphase bifunctional catalysts (Y-MSex/NF; M = Ni, Fe). Under high current circumstances, the linked structure of nanosheets and nanoscale microspheres created by hydrothermal selenium enhanced the catalytic reaction area and demonstrated exceptional performance. The overpotentials of the catalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were 350 mV and 340 mV, respectively, at a current density of 1000 mA cm−2(j1000). Moreover, stable operation in 1.0 M potassium hydroxide at a current density of 100 mA cm−2for 50 h further demonstrated the good electrocatalytic stability. Demonstrate the potential of selenides doped with the rare earth element yttrium for total water decomposition applications.

An ab-initio investigation of Sc and Y doped chalcopyrite MgGeN[formula omitted]

The doping of Scandium and Yttrium within chalcopyrite MgGeN2 were computationally investigated using density function theory (DFT) calculations. By calculating the formation energy, it was shown that independent single Sc and Y dopants energetically favor the occupation of the Mg site, inducing a shallow level within the conduction band. However, in the presence of a substitutional defect, the second dopant will occupy the neighboring Ge site. There is strong attractive interaction between two dopants, so that they are easily combined into a composite defect. In this case a shallow defect level appears above the valence band edge. Similar behavior is observed for the composite defects containing one dopant and an intrinsic cation vacancy, while those with one dopant and a nitrogen vacancy induce a deep defect level and greatly reduce the band gap. The investigation deepens the knowledge of Sc and Y doped II-IV-V2 compounds and may hence lead to more implementations.

Investigation of BaZrO3 Nanoparticles for Photocatalytic Activity and the Effects of Y-doping

A straightforward co-precipitation technique with yttrium doping (X = 0, 0.02, 0.04, 0.06) was used to fabricate perovskite Ba1−xYxZrO3 nanoparticles. Employing Powder X-ray diffraction (PXRD) technique, the compound was characterized and found to have a perovskite structure crystallized in a cubic lattice. Images from scanning electron microscopy (SEM) show plenty of pores between the grains and a structure resembling a rod. The purity and formation of B-site in the nanostructure was confirmed by a Fourier Transform Infrared (FT-IR) spectrophotometer. The UV-Vis profile and photoluminescence (PL) spectra of the powder were also ascertained. Using methylene blue as a model organic pollutant, the powder as a photocatalyst was tested for two hours under UV light irradiation. The Y-doped nanoparticles broke down the dye by ∼98.5% at pH = 8 when exposed to UV light. The enhanced photocatalytic performance exhibited by Y-doped BaZrO3 nanoparticles can be attributed to their efficient charge separation and increased adsorption capabilities by the presence of BaZrO3.

(Y3+/Sm3+)-doped and co-doped CoFe2O4 for heterogeneous advanced oxidation process: structural, magneto-optical, and photocatalytic investigations.

The photocatalytic properties of CoFe2O4 nanoparticles were activated by the doping and co-doping of a low level of Y3+ and Sm3+ cations. After optimizing the annealing temperature, 900°C was found to be the optimal temperature for the successful incorporation of Y3+ and Sm3+ into the spinel structure. The purity of our samples annealed at 900°C was confirmed using several characterization methods, including PXRD, SEM, XPS, VSM, FTIR, and Raman spectroscopy. Thus, we were able to increase the photocatalytic degradation of orange G dye from 9.9 to 64.63% for the Sm3+-doped sample, 76.42% for the Y3+-doped sample, and even 85.81% for the co-doped sample under 60min of UV-visible light irradiation. The beneficial effect of samarium and yttrium doping and co-doping is attributed to several factors: the first factor is doped and co-doped rare earth impurities induce distortion in the lattice, the larger the ionic radii of dopant element, the highest is the photocatalytic activity; second factor, upon doping and co-doping of rare earth impurities in the structure of CoFe2O4 leads to the creation of donor state level within the band gap, causing the Fermi energy to shift near the conduction band. Third factor, co-doping produced strong interactions, which accelerated photocarrier mobility and transport; lastly, longer electron-holes lifetime. We have provided a detailed study of the structural, vibrational, and optical properties to support our conclusions.

Enhanced stability and electrochemical performance of O3-type NaNi1/3Fe1/3Mn1/3O2 cathode material via yttrium doping for advanced sodium-ion batteries

Enhanced stability and electrochemical performance of O3-type NaNi1/3Fe1/3Mn1/3O2 cathode material via yttrium doping for advanced sodium-ion batteries

Simultaneously Boosting Direct and Indirect Urea Oxidation of Nickel Hydroxide via Strategic Yttrium Doping.

Urea electrolysis can address pressing environmental concerns caused by urea-containing wastewater while realizing energy-saving hydrogen production. Highly efficient and affordable electrocatalysts are indispensable for realizing the great potential of this emerging technology. Among the numerous candidates, α-Ni(OH)2 has the merits of good electrocatalytic activity, adjustable heteroelement doping, and low cost; consequently, it has received tremendous attention in the electrolytic fields. Herein, a Y3+-doping strategy is developed to effectively enhance the catalytic performance of nickel hydroxide in the urea oxidation reaction (UOR). Our results show that Y3+ incorporation successfully modulates the electronic structure of α-Ni(OH)2 by inducing Ni3+ formation in the crystal lattice to initiate direct UOR, facilitates the Ni3+/Ni2+ redox transition with higher current responses to promote indirect UOR, and maintains the structural stability of YNi-10 (Ni2+/Y3+ molar ratio = 1:0.1) during long-term UOR operation. Owing to these features, the obtained YNi-10 sample exhibits a higher current density (127 vs 79 mA cm-2 at 1.5 V), a lower Tafel slope (48 vs 75 mV dec-1), a larger potential difference between the UOR and oxygen evolution reaction (OER, 0.26 vs 0.22 V at 80 mA cm-2), a higher reaction rate constant (1.1 × 105 vs 3.1 × 103 cm3 mol-1 s-1), and a reduced activation energy of UOR (2.9 vs 14.8 kJ mol-1) compared with the Y-free counterpart (YNi-0). This study presents a promising strategy to simultaneously boost direct and indirect UORs, providing new insights for further developing high-performance electrocatalysts.

Ge-friendly gate stacks: Initial property and long-term reliability

This work presents specific exploration on the novel gate stack strategies for the intriguing Ge p-MOSFET, where high pressure oxidation (HPO) process is utilized for sufficient oxidation and thus fewer oxygen vacancies, while yttrium doping is developed to strengthen the dielectric bonding for higher ruggedness. Superior gate controllability and stability have been achieved correspondingly, where then detailed comparison on the gate dielectric reliability is conducted. The HPO based GeO2 gate stack exhibits larger susceptibility to the gate bias stress, and could even breakdown under negative bias, which has been attributed to the local bond breakage that facilitates the irreversible network change. The yttrium-doped GeO2, on the other hand, presents impressive ruggedness against gate bias stress. Based on detailed bond breakage analysis, cation-doping in GeO2 is suggested to be effective in enhancing the bond rigidness, promising for a wider safe operation range for the gate bias in Ge MOSFET.

Impact of dopants on electrical conductivity of proton-conducting SrHfO3 perovskite

For reliable long-term operation of solid oxide electrochemical devices for the hydrogen energy system, an electrolyte with high ionic conductivity and excellent chemical stability is required. SrHfO3-based perovskites are known for their high chemical resistance; however, their ionic conductivity must be increased. In the present research, the effect of doping with yttrium and ytterbium on the electrical properties of strontium hafnate was studied for the first time. The crystal structure, solubility limit of the dopants, morphology and electrical properties of SrHf1-xMxO3-δ (M = Y, Yb) materials were investigated by the X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, direct current four-probe technique, and impedance spectroscopy. The solubility limits of Y and Yb in SrHfO3 were found to lie slightly below x = 0.10. It was revealed that yttrium doping is more favorable for the grain growth and densification of ceramics. A comparative analysis of the influence of dopant type (Y, Yb and Sc) and concentration on the electrical properties of SrHfO3 is provided.

Fabricating hydrothermally robust ceramic membranes from amorphous yttrium-doped SiO2-ZrO2 composites

SiO2-ZrO2 ceramic composites are necessary for highly demanding separation processes. We demonstrated the efficacy of using yttrium doping to improve the hydrothermal stability of SiO2-ZrO2 composite-derived membranes. In long-term hydrothermal stability tests involving steam-N2 mixture permeation between 500–800 °C, N2 permeance for an undoped SiO2-ZrO2 membrane fabricated on an α-Al2O3 substrate decreased from 5.0 × 10−6 to 2.5 × 10−6 mol m−2 s−1 Pa−1 after 60 h between 500–700 °C and to 3.2 × 10−8 mol m−2 s−1 Pa−1 after 32 h at 800 °C. The yttrium-doped SiO2-ZrO2 membrane achieved a stable N2 permeance of 6.5 × 10−6 mol m−2 s−1 Pa−1 after 60 h between 500–700 °C, which decreased to 8.0 × 10−7 mol m−2 s−1 Pa−1 after 32 h at 800 °C. Microstructural analyses revealed that integrating yttrium into a SiO2-ZrO2 matrix suppressed segregation and aggregation rates of ZrO2 nanocrystals to form more stable microstructures.

Influence of yttrium doping on the photocatalytic behaviour of lanthanum titanate: a material for water treatment

Abstract Remediating water contamination greatly benefits from the removal of chemical as well as microbiological contaminants using the same substance. Yttrium-doped Lanthanum Titanate (LaY x Ti1−x O3, where x = 0 (LTO) and 0.05 (LYTO)) nanoparticles (NPs) synthesized by the auto-combustion method were already proven to have better antibacterial activities. The current study aims to investigate the photocatalytic degradation efficiency of the same sample for the organic pollutant Methylene Blue (MB) dye. Here, two vital and decisive characterization methods were employed: Raman spectroscopy for chemical and morphological features and X-ray photoelectron spectroscopy (XPS) for surface phase identification. The oxidation states of La3+ and Ti3+ ions have been deduced using XPS. The HRTEM reveals the nano-structure with SAED pattern is supporting with XRD data. LaTiO3 (LTO) and LaY0.05Ti0.95O3 (LYTO) nanoparticles showed degradation efficiencies of 40.26 % and 86.24 %, respectively, at degrading methylene blue (MB) dye after a reaction time of 90 min. The degradation efficiency of LTO increased to 87.19 % after a reaction time of 150 min. The introduction of yttrium doping into lithium titanate demonstrates promise as a material for mitigating water treatment, as it augments the material’s antibacterial and photocatalytic characteristics.

Effect of Yttrium doping on enhancing the photocatalytic performance of TiO2/GO nanocomposite

Pure and Yttrium doped Titania/Graphene oxide (YTGO) nanocomposites were synthesized by hydrothermal method. XRD analysis confirmed the crystal structure and anatase phase of TiO2 nanoparticles. The anatase phase of TiO2 has been retained in the composite as confirmed from the XRD pattern. SEM and TEM images revealed that the spherical TiO2 nanoparticles are embedded into sheet like structures of GO. The size of the spherical nanoparticles in the composites is relatively smaller than that of pure sample due to anchoring on the GO sheets. The photocatalytic performance of TiO2 has significantly increased in the Y-doped TiO2 with GO compared to pure TiO2 and TiO2/GO (TGO). Moreover, 0.7 % Y-doped TiO2/GO nanocomposite exhibited superior photocatalytic performance with overall efficiency of 97 % compared to other samples. The 0.7 % Y-doped TiO2/GO nanocomposite shows higher rate constant and shorter half life time compared to other samples. The enhancement of photocatalytic activity of YTGO composites attributed to the combination of increased absorption due to the absorption edge shift and effective separation of photo generated carriers.

Internal strain identification of seed-layered ZrO2, aluminum-, and yttrium-doped ZrO2 thin films via grazing incidence x-ray diffraction

Grazing incidence x-ray diffraction reveals that conventional post-deposition-annealed ZrO2 and in situ crystallized (by local epitaxy) ZrO2 thin films (<15 nm) have different internal strain states. A comparison between single- and two-step grown films enables the diverse strain components to be discretely identified. In particular, thickness-dependent intrinsic growth strain is unevenly distributed within the film according to the Volmer–Weber growth. Furthermore, extrinsic thermal strain, locally present in the annealed seed layer, does not spread over the in situ crystallized upper main layer of the two-step film. Post-deposition annealing of the two-step film renders the strain state identical to the single-step films by imposing thermal strain on the in situ crystallized main layer. Local strains created by diffused aluminum and yttrium dopants are also examined. Since each stress factor plays a vital role in the phase formation and electrical behaviors of ZrO2 and other fluorite-structure films, this method will pave the way for understanding the film's internal strain distribution and accompanying performance engineering.

Leakage current control of Y-HfO2 for dynamic random access memory applications via ZrO2 stacking

Pristine HfO2 tends to have a monoclinic phase with a low dielectric constant. Reportedly, yttrium(Y) doping has been used to induce the tetragonal phase in HfO2, with Y contributing to the formation of the tetragonal phase and improving the crystallinity. However, Y doping in HfO2 forms oxygen vacancies, resulting in a relatively high leakage current. Owing to the difficulty in suppressing the oxygen vacancies crucial for inducing the tetragonal phase, we focused on another significant leakage current path: the grain boundary. Introducing a heterostructure is expected to reduce the grain size and mitigate the leakage current by increasing the length of the leakage path. This study compares the dielectric constant and leakage current based on the stacking sequence of ZrO2 and Y-doped HfO2 (Y-HfO2) and elucidate the underlying differences through electrical analysis. Additionally, crystallographic analysis reveals the reasons for the structural order-dependent variations in the electrical properties. Finally, the structure with a Y-HfO2 layer at the bottom demonstrates advantages in achieving a lower leakage current.

Yttria-Stabilized Zirconia Composite Coating as Barrier to Reduce Hydrogen Permeation into Steel.

Hydrogen atoms can enter into metallic materials through penetration and diffusion, leading to the degradation of the mechanical properties of the materials, and the application of hydrogen barrier coatings is an effective means to alleviate this problem. Zirconia coatings (ZrO2) have been widely studied as a common hydrogen barrier coating, but zirconia undergoes a crystalline transition with temperature change, which can lead to volumetric changes in the coating and thus cause problems such as cracking and peeling of the coating. In this work, ZrO2 coating was prepared on a Q235 matrix using a sol-gel method, while yttria-stabilized zirconia (YSZ) coatings with different contents of rare earth elements were prepared in order to alleviate a series of problems caused by the crystal form transformation of ZrO2. The coating performances were evaluated by the electrochemical hydrogen penetration test, pencil hardness test, scratch test, and high-temperature oxidation test. The results show that yttrium can improve the stability of the high-temperature phase of ZrO2, alleviating the cracking problem of the coating due to the volume change triggered by the crystalline transition; improve the consistency of the coating; and refine the grain size of the oxide. The performance of YSZ coating was strongly influenced by the yttria doping mass, and the coating with 10 wt% yttria doping had the best hydrogen barrier performance, the best antioxidant performance, and the largest adhesion. Compared with the matrix, the steady-state hydrogen current density of the YSZ coating decreased by 72.3%, the antioxidant performance was improved by 65.8%, and the ZrO2 coating hardness and adhesion levels were B and 4B, respectively, while YSZ coating hardness and adhesion were upgraded to 2H and 5B. With the further increase in yttrium doping mass, the hardness of the coating continued to improve, but the defects of the coating increased, resulting in a decrease in the hydrogen barrier performance, antioxidant performance, and adhesion. In this work, the various performances of ZrO2 coating were significantly improved by doping with the rare earth element, which provides a reference for further development and application of oxide coatings.

Effects of amorphous phase and yttrium on flash sintering and microstructures of ZrO2–SiO2 ceramic nanocomposites

AbstractFlash sintering has been used to consolidate a wide range of ceramics and ceramic composites. However, flash sintering of ceramic nanocomposite with a substantial amorphous phase is rarely studied. Meanwhile, the effects of yttrium addition on the flash sintering behaviors and microstructures of ZrO2‐based ceramic nanocomposite remain unknown. Herein, ZrO2‐SiO2 crystalline‐amorphous ceramic nanocomposites (CACNs) with different contents of amorphous phase and two types of yttrium dopants were sintered by flash sintering. Results showed that the content of amorphous phase (SiO2) had significant effects on the flash sintering behavior. The CACN with 65 mol% SiO2 was nonflash sinterable due to the high electric resistivity of SiO2, whereas, the CACN with 45 mol% SiO2 can be flash sintered to high densification within 35 seconds. The flash‐sintered CACNs consisted of ZrO2 nanocrystallites distributed in an amorphous SiO2 matrix. Flash sintering enhanced the tetragonal‐to‐monoclinic phase transformation of ZrO2. In addition, influences of yttrium dopant on CACNs were also investigated. Yttrium dopants can rapidly dissolve in ZrO2 lattices and show a tetragonal phase stabilization effect during flash sintering. Firework‐like ZrO2 microcrystallites formed by dendritic growth were observed close to the cathode region, which was attributed to athermal electric field effects and the formation and aggregation of oxygen vacancies at the cathode region. The results would provide guidance for fabricating CACNs via flash sintering.

Upconversion multicolor tuning in Er3+ and Yb3+ doped yttrium oxide prepared by precursor technique

The (Y0.9Er0.1-xYbx)2O3 (x = 0, 0.02, 0.05, 0.07, 0.08, 0.09) and Y1-(0.02+y)Er0.02YbyO3 (y = 0.05, 0.07, 0.09, 0.11) solid solutions have been synthesized by the precursor technique using mixed anhydrous formates. The crystal structure of ytterbium formate, Yb(HCOO)3, was established for the first time. The structural parameters and phase purity of the synthesized precursors and oxides were determined by X-ray phase analysis. The average sizes of crystallites are in the 60–80 nm range. The upconversion spectra of solid solutions exhibit a weak green and an intense red line attributed to 2H11/2,4S3/2→4I15/2 and 4F9/2→4I15/2 transitions of Er3+ ions. The green and red emissions of (Y0.9Er0.1-xYbx)2O3 and Y1-(0.02+y)Er0.02YbyO3 oxides are caused by two-photon conversion processes. The effect of dopant (erbium and ytterbium) concentration and Er3+/Yb3+ ratio on the intensity of upconversion emission were established, the contribution of upconversion green luminescence decreases with increasing the ytterbium concentration.

Concentration effects on the local structures and electronic properties of Er x BaY2− x F8: a first-principles study

Er3+ doped barium yttrium fluoride (BaY2F8) crystal has gained long-term attention due to its great potential in laser and medical device applications. However, the local structures of Er3+ doped BaY2F8 system (Er:BYF) remain uncertain, and the effect of doping concentration on structures and properties is unknown. Therefore, in this study, the first-principles study of the structural evolution of Er x BaY2−x F8 (x = 0.125, 0.25) crystals was carried out. By means of density functional theory and particle swarm optimization algorithm, the stable structures of Er:BYF crystals with two different concentrations are shown as standard monoclinic structures with P2 symmetry for the first time. The impurity Er3+ ions successfully enter the main lattice, replacing the Y3+ ions, and forming a [ErF8]5− polyhedron with C 2 point group symmetry. By calculating the electronic properties, the band gap values of the two structures are significantly reduced compared with that of pure BaY2F8 crystal. However, the conduction band does not break through the Fermi level, and the crystals still maintain the insulation characteristic. According to the calculation of the electron local density function, we conclude that Er–F and Y–F in Er:BYF are connected by ionic bonds. These results fill a theoretical gap in the study of Er:BYF crystals and provide inspiration for structural evolution and material design at different doping concentrations.

Impedance and Dielectric Analysis of Nickel Ferrites: Revealing the Role of the Constant Phase Element and Yttrium Doping

This paper presents the analysis of electrical and dielectric properties of the yttrium-doped nickel ferrite nano-powders synthesized using the co-precipitation method. Impedance and dielectric measurements have been carried out as a function of frequency at different temperatures from 200 to 25 °C in the range of 0.1 kHz–1 MHz. In order to investigate the conduction mechanism and highlight the role of yttrium doping in different concentrations, impedance spectroscopy was employed. The obtained data were analyzed in terms of equivalent circuits made of resistor and capacitor components describing the contributions from different electrical active regions in a material. Further, this study highlights the importance of a single constant phase element (CPE) in the description of dispersion behavior of the impedance response of the investigated samples in the given frequency range. The use of this technique enabled the characterization of grain and grain boundaries contribution in overall conductivity mechanism. The dielectric dispersion nature of all investigated materials is reflected in this study. Very high values of the real part of permittivity at low frequencies are assigned to space-charge polarization. The dependence of the real part of dielectric permittivity values of the yttrium content was also discussed. Doping with yttrium in different concentrations that reflects in different electric and dielectric responses is concluded in this study. The greatest change is noticed for the sample with the minimum dopant content for a x = 0.05 atomic percent share of yttrium. To reveal the potential role of more than one ion contribution to the overall relaxation process in investigated compounds, a modified Debye’s equation was utilized.

Lithium corrosion resistance of aluminum nitride prepared by structural doping with various elements

Influences of various doping elements on the corrosion behavior and possible failure mechanism of aluminum nitride ceramic in lithium had been investigated using X-ray diffraction and scanning electron microscope techniques. The results showed that different doping element could produce obvious effects on the corrosion behavior of aluminum nitride. In comparison with yttrium doping, better corrosion resistance in lithium could be achieved in zirconia doped aluminum nitride. This was attributed to a certain degree of compatibility of both the doped zirconium and its related compounds with lithium. Based on these observations, a corrosion resistance mechanism model was proposed, in which lithium was supposed to be hindered from diffusing into aluminum nitride by a network structure with the impurities, ie. ZrN and Al2.85N0.5O3.5, as the nodes. The corrosion resistance could also be improved effectively by fine and homogeneous grains due to the influences of grain sizes on the node number in network structure. Further studies on the corrosion behavior in embedded liquid lithium implied that the severity of corrosion had close relations with the sample surface quality.