Yttrium Aluminum Borate Research Articles

One-step modified combustion synthesis of yttrium aluminum borate phosphor doped with europium for long lasting solid-state lighting

The red-emitting phosphor YAl3(BO3)4: Eu3+(Yttrium Aluminum Borate) is synthesized by a simple, time-saving, economical novel method of solution combustion synthesis at 500 °C, a comparatively lower temperature using urea and glycine as fuel. In this work, the phosphor YAl3(BO3)4: Eu3+ is synthesized for the first time in one step at 500 °C by the combustion method. Europium as a doping in Yttrium Alunium borate phosphor gives intense emission in the red region having a prominent emission band at 614 nm with the excitation at 395 nm. This excitation band at 395 nm makes phosphor, a good red emitter for the n-UV LED for making w-LED for solid-state lighting. The phosphor YAl3(BO3)4: Eu3+ was also investigated for long-lasting or persistent luminescence for the first time. We observed long-lasting emission in the YAl3(BO3)4: Eu3+phosphor treated in reducing atmospheres, upon UV irradiation (254 nm) using emission from a Xe lamp (Hitachi F-7000).

Characterization, room and low temperature photoluminescence of yttrium aluminium borate activated with Sm3+ ions

In this study, the combustion method assisted by urea that is ideally suited to economic and time saving was used for the synthesizing of reddish orange emitting YAl3(BO3)4 phosphor samples doped with various Sm3+ ions (from 0.01 wt% to 7wt%). A detailed study of the structural and luminescence properties at room/low temperature of the synthesized samples was performed. XRD analysis revealed a rhombohedral structure with an R32 space group (155). The particle size was determined by the Scherrer's method to be 48 nm. The visible PL emission spectra upon excitation at 359 nm are recorded and four emission peaks around 564, 599, 646, and 707 nm with transitions 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, 4G5/2 → 6H9/2 and 4G5/2 → 6H11/2 are observed. Concentration quenching was mainly caused by dipole-dipole interactions between neighbouring trivalent Sm3+ ions. Through the CIE chroma coordinates (0.606, 0.382), the optimized sample (x = 0.03) demonstrates admirable luminous performance. YAl3(BO3)4:Sm3+ can be a good candidate for use as a red component for lighting applications.

Manganese Luminescent Centers of Different Valence in Yttrium Aluminum Borate Crystals.

We present an extensive study of the luminescence characteristics of Mn impurity ions in a YAl3(BO3)4:Mn crystal, in combination with X-ray fluorescence analysis and determination of the valence state of Mn by XANES (X-ray absorption near-edge structure) spectroscopy. The valences of manganese Mn2+(d5) and Mn3+(d4) were determined by the XANES and high-resolution optical spectroscopy methods shown to be complementary. We observe the R1 and R2 luminescence and absorption lines characteristic of the 2E ↔ 4A2 transitions in d3 ions (such as Mn4+ and Cr3+) and show that they arise due to uncontrolled admixture of Cr3+ ions. A broad luminescent band in the green part of the spectrum is attributed to transitions in Mn2+. Narrow zero-phonon infrared luminescence lines near 1060 nm (9400 cm-1) and 760 nm (13,160 cm-1) are associated with spin-forbidden transitions in Mn3+: 1T2 → 3T1 (between excited triplets) and 1T2 → 5E (to the ground state). Spin-allowed 5T2 → 5E Mn3+ transitions show up as a broad band in the orange region of the spectrum. Using the data of optical spectroscopy and Tanabe-Sugano diagrams we estimated the crystal-field parameter Dq and Racah parameter B for Mn3+ in YAB:Mn as Dq = 1785 cm-1 and B = 800 cm-1. Our work can serve as a basis for further study of YAB:Mn for the purposes of luminescent thermometry, as well as other applications.

Anisotropy of the Electromechanical Characteristics of SH-Waves and Lamb Waves in Yttrium Aluminum Borate Single Crystals

The anisotropy of the electromechanical properties of SH-waves and Lamb waves in yttrium aluminum borates, which are nonmagnetic representatives of the RMe3(BO3)4 single crystals family (where R=Y, La-Lu; M=Fe, Al, Cr, Ga, Sc) with unique properties of magnetoelectrics and multiferroics, has been studied. In the process of the numerical simulation of the acoustic waves characteristics, the values of linear electromechanical constants of YAl3(BO3)4 single crystals, previously measured by ultrasonic pulse echo and quasi-static methods, have been used

Studies on Structural, optical and Magnetic properties of Yttrium Aluminum Bromate (YAB) Nanomaterials, prepared at high annealing temperature

In this research, we present structural, photo-luminescence and magnetic properties of the Yttrium Aluminum Borate (YAB) nanomaterial, synthesized by low-cost Sol-gel method in high temperature range. X-ray diffraction (XRD) analysis, shows that crystal structure of YAB is of nanometric size ranging between 38 nm to 47 nm for the annealing temperature above 900°C. Photoluminescence property shows that YAB gives intense Blue light emission in the visible region. High-temperature annealing was found to increase the grain size and enhance the blue luminescence. Vibrating Sample Magnetometer (VSM) shows that coercivity increases while Magnetization and retentivity decreases for YAB nanomaterials for the temperature above 900 degree Celsius. Prepared YAB materials may be useful for LED or related devices.

Structural, optical, and magnetic properties of Yttrium aluminium BORATE (YAB) nanomaterial, prepared by low cost sol–gel chemical method

In this paper, we present synthesis, structural optical, and magnetic analysis, of the Yttrium Aluminium Borate (YAB) nanomaterials. YAB materials were synthesized by the Sol-gel method. The structural analysis, carried out by using X-ray diffraction (XRD) and shows that the crystal structure of YAB is of nanometric size ranging between 16 nm and 26 nm at annealing temperature above 800 °C. Photoluminescence property shows that YAB gives intense blue light emission in the visible region. Further energy band gap were investigated using Tauc plot which was found to be decreased from 1.782 eV to 1.748 eV respectively with increasing annealing temperature from 800 °C to 900 °C, keeping annealing time constant for 2 hrs. Energy band gap is a function of crystallite size and it is very close to energy band gap of GaAs nanomaterial used in the Light Emitting Diode (LED) application, having band energy gap 1.441 eV. Vibrating Sample Magnetometer (VSM) measurement shows the diamagnetic nature of the prepared sample. Coercivity increases while Magnetization and retentivity decrease for YAB nanomaterial for the temperature above 800 °C Celsius. The prepared YAB nanomaterials may be a potential candidate for LED and other related applications.

Bifunctional LaxNdyGdzSc4−x−y−z(BO3)4 crystal: Czochralski growth, linear and nonlinear optical properties, and near-infrared laser emission performances

High optical quality LaxNdyGdzSc4−x−y−z(BO3)4 (Nd:LGSB) single crystal has been obtained by the Czochralski technique. The crystal composition was found to be La0.721Nd0.046Gd0.452Sc2.781(BO3)4. Low-temperature spectroscopic investigations revealed that the Nd3+ ions enter only in La3+ ions sites. The main nonlinear optical (NLO) properties of Nd:LGSB (4.6 at.%) crystal were found to be comparable to those of yttrium aluminum borate (YAB) crystal. Laser emission at 1.06 µm with 24.5 mJ energy per pulse for 35.6 mJ absorbed pump pulse energy at 807 nm and 0.71 slope efficiency has been obtained from a c-cut Nd:LGSB (4.6 at.%) uncoated crystal sample with 6.14 mm length. Slope efficiency as high as 0.73 was obtained from an uncoated 2.96 mm thick a-cut sample. The good NLO properties of Nd:LGSB crystal together with the excellent near-infrared laser performances, recommends Nd:LGSB as a very promising bifunctional crystal in self-frequency doubling configuration.

Liquid-Phase Epitaxial Growth and Characterization of Nd:YAl3(BO3)4 Optical Waveguides

We investigated the fabrication of neodymium doped thin film optical waveguide-based devices as potential active sources for planar integrated optics. Liquid-phase epitaxial growth was used to fabricate neodymium-doped yttrium aluminum borate films on compatible lattice-matched, un-doped yttrium aluminum borate substrates. We observed the refractive index contrast of the doped and un-doped crystal layers via differential interference contrast microscopy. In addition, characterization by X-ray powder diffraction, optical absorption and luminescence spectra demonstrated the crystal quality, uniformity and optical guiding of the resulting thin films.

Theoretical studies of the EPR parameters and local structure for the trigonal Yb3+ center in YAl3(BO3)4 crystal

Yttrium aluminium borate crystals have excellent physical and chemical properties. In this paper, the electron paramagnetic resonance (EPR) g factors g//, g^ of Yb3+ and hyperfine structure constants A//, A^ of 171Yb3+ and 173Yb3+ isotopes in YAl3(BO3)4 crystal are calculated from the perturbation formulas. The crystal field parameters are obtained from the superposition model and the crystal structure data. The EPR parameters for trigonal Yb3+ centers in YAl3(BO3)4 are reasonably explained by considering the defect structures of doped Yb3+ centers. In the calculation, we also find that Yb3+ ion does not exactly reside in Y3+ site, but suffers an angle distortion Dq (≈ 3.98 Å) with C3 axis. The results are discussed.

Modeling and Implementing Nonlinear Equations in Solid-State Lasers for Studying their Performance

In this paper, the effect of radius variation of beam light on output efficacy of SFD Yttrium aluminium borate laser doped with Neodymium ion, which is simultaneously a non-linear and active laser crystal, is investigated in a double-pass cavity. This is done with a concave lens that concentrates (Reduction of optical radius within nonlinear material) as much optical laser as possible, resulting in increasing the laser efficiency, second harmonic and the population inversion difference. In this study, we first developed five discrete differential equations describing the interactions of 807 nm pump beam, 1060nm laser beam and 530nm second harmonic beam. Output efficiencies of laser and second harmonic beams at pumping power of Pp =20W and beam radius of 5μm have been presented. Meanwhile, in this paper, the first experiment for creating second harmonic in solid state lasers was fully described with a figure and its procedure was investigated and then the equations (second harmonic and laser and population inversion) were studied. Radius variation of beam light aims at increasing laser output efficacy and improving second harmonic and population inversion. The analytic methods which have been solved the discrete differential equations via Matlab.

Electron Paramagnetic Resonance of Cr-=SUP=-3+-=/SUP=- Ions in Single Crystals of Yttrium Aluminum Borate YAl-=SUB=-3-=/SUB=-(BO-=SUB=-3-=/SUB=-)-=SUB=-4-=/SUB=--=SUP=-*-=/SUP=-

AbstractSingle crystal of yttrium aluminum borate YAl_3(BO_3)_4 doped with chromium ions (1 at %) was studied using electron paramagnetic resonance spectroscopy. It is shown that chromium ions introduced into the sample occupy yttrium ion sites in the crystal structure. The parameters of the spin Hamiltonian of Cr^3+ ions in the YАl_3(ВО_3)_4 matrix are determined at different temperatures. The sign of the fine structure parameter D allows the conclusion that the chromium ions in YА1_3(ВО_3)_4 single crystals have an easy-plane anisotropy.

Evidence of Organic Luminescent Centers in Sol–Gel‐Synthesized Yttrium Aluminum Borate Matrix Leading to Bright Visible Emission

Yttrium aluminum borate (YAB) powders prepared by sol-gel process have been investigated to understand their photoluminescence (PL) mechanism. The amorphous YAB powders exhibit bright visible PL from blue emission for powders calcined at 450 °C to broad white PL for higher calcination temperature. Thanks to 13 C labelling, NMR and EPR studies show that propionic acid initially used to solubilize the yttrium nitrate is decomposed into aromatic molecules confined within the inorganic matrix. DTA-TG-MS analyses show around 2 wt % of carbogenic species. The PL broadening corresponds to the apparition of a new band at 550 nm, associated with the formation of aromatic species. Furthermore, pulsed ENDOR spectroscopy combined with DFT calculations enables us to ascribe EPR spectra to free radicals derived from small (2 to 3 rings) polycyclic aromatic hydrocarbons (PAH). PAH molecules are thus at the origin of the PL as corroborated by slow afterglow decay and thermoluminescence experiments.

Evidence of Organic Luminescent Centers in Sol–Gel‐Synthesized Yttrium Aluminum Borate Matrix Leading to Bright Visible Emission

AbstractYttrium aluminum borate (YAB) powders prepared by sol–gel process have been investigated to understand their photoluminescence (PL) mechanism. The amorphous YAB powders exhibit bright visible PL from blue emission for powders calcined at 450 °C to broad white PL for higher calcination temperature. Thanks to 13C labelling, NMR and EPR studies show that propionic acid initially used to solubilize the yttrium nitrate is decomposed into aromatic molecules confined within the inorganic matrix. DTA‐TG‐MS analyses show around 2 wt % of carbogenic species. The PL broadening corresponds to the apparition of a new band at 550 nm, associated with the formation of aromatic species. Furthermore, pulsed ENDOR spectroscopy combined with DFT calculations enables us to ascribe EPR spectra to free radicals derived from small (2 to 3 rings) polycyclic aromatic hydrocarbons (PAH). PAH molecules are thus at the origin of the PL as corroborated by slow afterglow decay and thermoluminescence experiments.

Photoluminescence properties of glassy yttrium aluminum borate powders: Dopant-free phosphors for solid-state lighting

Glassy yttrium aluminum borate powders (g-YAB) obtained by the polymeric precursor method show intense photoluminescence (PL) in the visible range under near-ultraviolet (NUV) excitations. The PL properties strongly depend on the thermal treatment of powders as well as the excitation wavelengths. The broad PL of g-YAB powders cover whole visible spectral range between 380nm and 780nm under NUV excitations. The PL internal quantum yield (i-QY) was determined using the integrating sphere method and is found to reach up to 91±5% under 365nm light emitting diode (LED) excitation. Moreover, the associated color coordinates in transmission mode revealed preferably warm-white light with correlated color temperature (CCT) tunable between 2800K and 5300K, ideal for general household and workplace lighting. The use of NUV-LED excitation accompanied with broadband visible emission profile helps in achieving high color-rendering ability with color-rendering index (CRI) higher than 90. Furthermore, these g-YAB phosphors exhibit excellent PL thermal stability (>200°C) and stability with time under device operating conditions. The overall favorable PL properties and low cost synthesis suggest huge potential of g-YAB phosphors as new lanthanide (Ln)-free white light phosphors with very high CRI under NUV-violet LED excitations.

First-principles calculations and re-analysis of optical spectra and electron paramagnetic resonance parameters for Yb3+ in YAl3(BO3)4 crystal

In this paper, the energy levels of Yb3+ ions in yttrium aluminum borate (YAB) crystal were calculated from a first-principles approach with an optimized defect structure obtained from the WIEN2k package and a traditional fitting method using a more reliable computer package. The calculated results were then compared with those obtained from a re-calculation using the values of parameters given by some previous researchers. Three types of likely mistakes in the previous researcher's paper, namely over fitting, incorrect use of irreducible representation, and errors in the calculations for the EPR parameters were clearly identified and effectively rectified in this paper. The electron paramagnetic resonance (EPR) parameters, which included g factors like g// and g⊥ and hyperfine structure constants A// and A⊥, were also calculated through the perturbation method and compared with some observed values available in literature. There was reasonable agreement found with the experimental values which lay between the values obtained from the first-principles calculation (g//=4.000 and g⊥=1.391; A//=1032 and A⊥=360 in 10−4 cm−1 for 171Yb3+) and those from the fitting approach (g//=3.612 and g⊥=1.702; A//=867 and A⊥=470 in 10−4 cm−1 for 171Yb3+).

Determination of the microstructure, energy levels and magnetic dipole transition mechanism for Tm3+doped yttrium aluminum borate

Yttrium aluminum borate (YAB) doped with rare-earth ions are promising materials for infrared lasers and self-frequency summing laser systems.

Optical temperature sensing using a new thermographic phosphor

The luminescence emission of a new thermographic phosphor based on Chromium(III)-doped yttrium aluminum borate (Cr3+:YAB) has a strong temperature dependence, which makes this material well suited for temperature sensing. In this work the luminescence emission decay was investigated in great detail in a broad temperature range, both in time and frequency domain. The results obtained with these two measuring techniques, which are consistent, are used to determine the optimal design parameters for sensor development. The high sensitivity which is thus achievable, together with the high stability of the material, demonstrate that this phosphor is very suitable for the design of a sensitive, low-cost, and robust contactless temperature sensor. Due to the insensitivity of the sensing properties to the immobilization matrix, this material can be easily incorporated in the most appropriate matrix depending on the application.

Fluorescence properties of Sm3+ ions in yttrium aluminum borate phosphors for optical applications

Different concentrations of Sm3+-doped yttrium aluminum borate (YAl3(BO3)4) phosphors were prepared by solid-state reaction method. The phase analysis has been carried out by X-ray diffraction studies. Fluorescence properties were investigated through emission, excitation and decay measurements. Upon 404nm excitation, YAl3(BO3)4:Sm3+ phosphors exhibit their characteristic emission lines at 564nm (4G5/2→6H5/2), 600nm (4G5/2→6H7/2), 646nm (4G5/2→6H9/2) and 707nm (4G5/2→6H11/2). Both emission and excitation spectra show a luminescence quenching beyond 0.01mole concentration of Sm3+ ions due to the energy transfer among the excited Sm3+ ions at higher concentrations. The YAl3(BO3)4:0.01Sm3+ phosphor can be used as a promising material producing intense orange-red emission for various optical applications.

Correlation of EMR and optical spectroscopy data for Cr3+ and Mn2+ ions doped into yttrium aluminum borate YAl3(BO3)4 crystal – Extracting low symmetry aspects

In this study, the crystal field analysis for Cr3+ and Mn2+ ions doped into yttrium aluminum borate YAl3(BO3)4, for short YAB, crystal has been carried out to complement earlier study of the zero-field splitting (ZFS) parameters (ZFSPs). This analysis utilizes data on the distortion models obtained from analysis of the ZFSPs obtained experimentally by EMR for Cr3+ and Mn2+ ions at the Y3+ and Al3+ sites in YAB. This approach enables to verify and enhance reliability of the ZFSP modeling based on superposition model (SPM) analysis and the distortion models predicted previously. Subsequently, modeling of the crystal field parameters (CFPs) based on SPM analysis is carried out for Cr3+ and Mn2+ ions located at possible cation sites in YAB. The SPM predicted CFP values serve as input for the Crystal Field Analysis (CFA) package to calculate the CF energy levels. The predicted physical ZFS of the ground spin state, i.e. the 4A2 state for Cr3+ ion and the 6S state Mn2+ ions, enable calculation of the theoretical ZFSP values, D and D & (a–F), respectively, using the microscopic spin Hamiltonian (MSH) module in the CFA package. In this way, data on the distortions around the Cr3+ centers in YAB (and to a certain extent also for Mn2+ centers) obtained using the ZFSP data from EMR measurements may be correlated with data on the CF energy levels measured by optical spectroscopy. This modeling approach uncovers certain incompatibilities in the existing data for Cr3+:YAB, which call for reanalysis of the previous assignments of the energy levels observed in optical spectra and more accurate experimental data.

Synthesis and photoluminescence studies on YAl3(BO3)4:Tb3+phosphor

Terbium (Tb 3+ ) doped yttrium aluminium borate phosphors (YAl 3 (BO 3 ) 4 ) with different compositions such as YAl 3 (BO 3 ) 4 :Tb 3+ , Y 1− x Al 3 (BO 3 ) 4 :Tb x 3+ and YAl (3− x ) (BO 3 ) 4 :Tb x 3+ ( x = 1−8 mol.%) were synthesized using modified solid state reaction technique. The synthesized phosphor was studied using powder X-ray diffraction analysis (XRD), photoluminescence spectroscopy (PL), high resolution-scanning electron microscope (HR-SEM). Lattice parameters are calculated for the Tb 3+ doped and substituted YAB phosphors using XRD analysis. The phosphor exhibits green emission at 572 nm with 375 nm of excitation. It is found that the Tb 3+ ions substitution in the sites Y 3+ and Al 3+ ions in Y 1– x Al 3 (BO 3 ) 4 :Tb x 3+ and YAl (3– x ) (BO 3 ) 4 :Tb x 3+ leads to overlapping of energy levels which affects the PL intensity of the phosphor significantly. Thus, phosphor synthesized with the composition YAl 3 (BO 3 ) 4 :Tb 3+ , acquires higher photoluminescence (PL) intensity when compared to Y 1– x Al 3 (BO 3 ) 4 :Tb x 3+ and YAl (3– x ) (BO 3 ) 4 :Tb x 3+ phosphors. Temperature dependent PL property (thermal quenching studies) of YAl 3 (BO 3 ) 4 :Tb 3+ was also performed up to 250 °C. Further, it is found that the PL intensity of the studied phosphor is comparable with commercial green phosphor. HR-SEM analysis demonstrates that the phosphors are grown as nanorods with an average diameter of 50–80 nm and length 250–500 nm.