Luminescence study of iron doped lithium aluminate phosphor (original) (raw)
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Combustion synthesis , characterization and luminescence properties of barium aluminate phosphor
The blue-green emitting Eu2+ and Nd3+ doped polycrystalline barium aluminate (BaAl2O4:Eu2+,Nd3+) phosphor, was pre- pared by a solution-combustion method at 500 ºC without a post-annealing process. The characteristic variation in the structural and luminescence properties of the as-prepared samples was evaluated with regards to a change in the Ba/Al molar ratio from 0.1:1 to 1.4:1. The morphologies and the phase structures of the products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), while the optical properties were investigated using ultra-violet (UV) and photoluminescence (PL) spectroscopy, respectively. The XRD and TEM results revealed that the average crystallite size of the BaAl2O4:Eu2+,Nd3+ phosphor was about 70 nm. The broad-band UV-excited luminescence of the phosphors was observed at λmax=500 nm due to transitions from the 4f65d1 to the 4f7 configuration of the Eu2+ ion. The PL results indi- cated that the main peaks in the emission and excitation spectrum of phosphor particles slightly shifted to the short wavelength due to the changes in the crystal field due to the structure changes caused by the variation in the quantity of the Ba ions in the host lattice.
EPR and luminescence properties of combustion synthesized LiAl5O8:Mn phosphors
Materials Chemistry and Physics, 2008
LiAl 5 O 8 :Mn 2+ phosphors have been synthesized by combustion process in a short time (<5 min). X-ray diffractogram confirms that the synthesized material consists of LiAl 5 O 8 as main phase. Scanning electron microscopy showed angular plate-like crystals with non-uniform shape. The EPR spectra of Mn 2+ ions exhibit resonance signals at g ≈ 4.28 and g ≈ 2.0. The signal at g ≈ 2.0 is due to Mn 2+ ions in an environment close to tetrahedral symmetry, whereas the resonance at g ≈ 4.28 is attributed to the rhombic surroundings of the Mn 2+ ions. The variation of zero-field splitting parameter (D) with temperature is measured and discussed. The PL spectra exhibit green emission peaks at 505 and 518 nm which are due to the 4 T 1 (G) → 6 A 1 (S) transition of Mn 2+ ions. The EPR study of LiAl 5 O 8 :Mn 2+ phosphor gives clear indication of the Mn 2+ ions occupying more than one site in this phosphor.
Luminescence Properties of Calcium Aluminate Phosphors
2019
Luminescence properties of CaAl2O4 were studied. Rare earth Eu2+ doped alkaline earth aluminate CaAl2O4 phosphor was prepared by combustion synthesis using urea as a fuel at 600 °C. It was found that firstly the TL intensity increases with increase in UV irradiation time and it attains a maximum value for 15 minute irradiation time. TL intensity decreases with further increase in irradiation time. In photoluminescence (PL) spectrum, a broad emission peak of Eu2+ ion was observed in blue region at 441 nm, under 363 nm excitation due to transition from the 4f65d1 to the 4f7 configuration of the Eu2+ ion. Optimum intensity of photoluminescence (PL) was found to be 0.05 mol% concentration of Eu2+.
Journal of Materials Science: Materials in Electronics, 2015
In the present investigation dysprosium doped strontium aluminate phosphor was prepared by combustion synthesis method. The crystal structure of the prepared phosphor was consistent with standard monoclinic phase with a space group P2 1. According to the TEM analysis, the particle size was found to be in the nanometer range. The trap parameters which are mainly activation energy (E), frequency factor (s) and order of the kinetics (b) were evaluated by using the peak shape method. Under the ultraviolet (365 nm) excitation, photoluminescence (PL) spectra showed characteristic emission bands at 480 (blue), 573 (yellow) and 670 nm (red) due to 4 F 9/2 ? 6 H 15/2 , 4 F 9/2 ? 6 H 13/2 and 4 F 9/2 ? 6 H 11/2 transitions of Dy 3? ions. Combination of these three emissions constituted as white light confirmed by the Commission Internationale de L'Eclairage (CIE) chromatic coordinate diagram and possible mechanism of white light emitting SrAl 2 O 4 :Dy 3? phosphor was also investigated. The value of correlated color temperature (CCT) was found, well within the defined acceptable range (5965 K). The mechanoluminescence (ML) intensity of SrAl 2 O 4 :Dy 3? phosphor increases linearly with increasing impact velocity of the moving piston. Thus, the present investigation indicates the piezoelectricity was responsible to produce ML in prepared phosphor.
Synthesis and luminescence property of Li2BaP2O7:Ln3+ (Ln=Eu, Sm) phosphors
Journal of Luminescence, 2014
Phosphate compounds as host materials are always a good choice for lanthanides to exhibit luminescence. The novel phosphors of Li 2 BaP 2 O 7 activated with the trivalent Eu 3 þ and Sm 3 þ ions were synthesized by high temperature solid state reaction. In characterization, crystallization, morphology and luminescent properties of lithium barium diphosphate were investigated. The excitation and emission spectra were recorded to study the luminescence properties. The as prepared powders of Eu 3 þ and Sm 3 þ ions doped Li 2 BaP 2 O 7 emit reddish orange light, corresponding to 5 D 0-7 F 1 (595 nm) and 4 G 5/2-6 H 7/2 (599 nm) transitions, respectively. The study is novel as no such luminescence data are available for this compound.
Synthesis and luminescence property of Li2BaP2O7:Ln3þ (Ln¼Eu, Sm) phosphors
Phosphate compounds as host materials are always a good choice for lanthanides to exhibit luminescence. The novel phosphors of Li2BaP2O7 activated with the trivalent Eu3þ and Sm3þ ions were synthesized by high temperature solid state reaction. In characterization, crystallization, morphology and luminescent properties of lithiumbariumdiphosphate were investigated. The excitation and emission spectrawere recorded to study the luminescence properties. The as prepared powders of Eu3þ and Sm3þ ions doped Li2BaP2O7 emit reddish orange light, corresponding to 5D0-7F1(595 nm) and 4G5/2-6H7/2(599 nm) transitions, respectively. The study is novel as no such luminescence data are available for this compound.
Aluminate-Based Nanostructured Luminescent Materials: Design of Processing and Functional Properties
Materials, 2021
Interest in luminescent materials has been continuously growing for several decades, looking for the development of new systems with optimized optical properties. Nowadays, research has been focused on the development of materials that satisfy specific market requirements in optoelectronics, radioelectronics, aerospace, bio-sensing, pigment applications, etc. Despite the fact that several efforts have made in the synthesis of organic luminescent materials, their poor stability under light exposure limits their use. Hence, luminescent materials based on inorganic phosphors are considered a mature topic. Within this subject, glass, glass-ceramics and ceramics have had great technological relevance, depending on the final applications. Supposing that luminescent materials are able to withstand high temperatures, have a high strength and, simultaneously, possess high stability, ceramics may be considered promising candidates to demonstrate required performance. In an ongoing effort to f...
Combustion synthesis and preliminary luminescence studies of LiBaPO4 : Tb3+ phosphor
Bulletin of Materials Science, 2015
The polycrystalline sample of LiBaPO 4 : Tb 3+ (LBPT) was successfully synthesized by solution combustion synthesis and studied for its luminescence characteristics. The thermoluminescence (TL) glow curve of LBPT material consists of two peaks at 204.54 and 251.21 • C. The optimum concentration was 0.005 mol to obtain the higher TL intensity compared to commercial TLD-100 phosphor. The peak shape method was used to calculate kinetic parameter (activation energy and frequency factor). In CW-OSL mode its sensitivity for beta exposure was found to be 50% compared to commercially available α-Al 2 O 3 : C and 40% than LMP (BARC), and photoluminescence spectrum of LBPT shows green emission when excited with 225 nm UV source.
The influence of processing parameters on luminescent oxides produced by combustion synthesis
Displays, 1999
Rare-earth activated oxide phosphors have application in high energy photoluminescent (plasma panels) and cathodoluminescent (field emission devices) flat panel displays. These phosphors are composed of a highly insulating host lattice with fluorescence arising from the 3d 3 3d, 5d 3 4f or 4f 3 4f transitions in transition metal or rare earth ions. Fabrication of complex host compositions Y 2 SiO 5 , Y 3 Al 5 O 12 , Y 2 O 3 , and BaMgAl 10 O 27 along with controlled amounts of the activators (Cr 3ϩ , Mn 2ϩ , Ce 3ϩ , Eu 2ϩ , Eu 3ϩ , Tb 3ϩ , Tm 3ϩ) represent a challenge to the materials synthesis community. High purity, compositionally uniform, single phase, small and uniform particle size powders are required for high resolution and high luminous efficiency in the new flat panel display developments. This paper will review the synthesis techniques and present physical and luminescent data on the resulting materials.
Luminescence study in Eu-doped aluminum oxide phosphors
Optical Materials, 2005
a-and c-(Al 1Àx Eu x ) 2 O 3 polycrystalline phosphor powders have been prepared via pressure assisted combustion synthesis at $280°C. The particle size could be controlled (nanoparticles/microparticles) by adjusting the initial pressure in the combustion reactor. Upon excitation at 394 nm, the Eu-doped alumina nanoparticles exhibited a strong photoluminescence due to a parity forbidden f-f intraconfigurational transition upon excitation at k = 395 nm. By analyzing the emission lines in the cathodoluminescence spectrum of the europium doped a-Al 2 O 3 sample it was inferred that the dopant ions occupy low symmetry sites in the host lattice. These powders are potentially good candidates for photonics applications.