ABSTRACT
One of the exciting developments in contemporary luminescence research is the development of rare earth triggered luminescent glasses, which are a type of lanthanide activated luminous material. For the first time, Ce3+, Eu3+ activated/co-activated Mg21Ca4Na4(PO4)18 orthophosphate glasses have been synthesized using the proposed work's melt quenching technique. The proposed glass sample's XRD pattern has an amorphous character, although its most prominent peak matches data from the Mg21Ca4Na4(PO4)18 standard ICSD database. FT-IR analysis was used to analyze the proposed glass sample's vibrational characteristics. Co-activated Mg21Ca4Na4(PO4)18 glass exhibits large emission peaks under UV excitations that cover the far red area during a photoluminescence examination. These outcomes demonstrate the proposed sample's value in applications such as WLEDs and plant cultivation.
ABSTRACT
Phosphites are the new emerging candidates in the field of luminescence in the modern era. In the present investigation, Tb3+/Eu3+ activated/co-activated LiAl(PO3)4 phosphor was prepared by a wet chemical method, and the effect of R+ (Na+, K+) ions on photoluminescence (PL) properties of these phosphors are investigated. Phase identification and crystal structure of the prepared phosphor were determined using XRD and Rietveld refinement, respectively. Morphological study and elemental analysis of the proposed phosphor with elemental analysis of the sample were performed using SEM and EDS. The PL properties of the proposed phosphor showed three simultaneous emission peaks in the visible range, giving color-tunable emission. The charge compensation of Na+ and K+ ions make a significant impact on the PL intensity of Tb3+, Eu3+ co-activated LiAl(PO3)4 phosphors. The PL intensity of Tb3+, Eu3+ co-activated LiAl(PO3)4 phosphors was significantly enhanced by factors 1.2 and 1.4 when Na+ and K+ charge compensators, respectively, were introduced. To manifest the charge compensation effect of alkali metals the optimum intense sample in the co-doped sample was used. These results indicate the potential candidacy of the studied phosphor for further improvement in PL properties for application in solid-state lighting.
ABSTRACT
This article focuses on the effect of monovalent cation doping on the optical properties of rare earth (RE = Eu3+ , Tb3+ ) co-doped Ca14 Zn6 Al10 O35 which has been synthesized by a low temperature combustion method. Crystalline phase of the Ca14 Zn6 Al10 O35 phosphor was examined and confirmed by X-ray diffraction measurement. Under near-ultraviolet light excitation Eu3+ -doped Ca14 Zn6 Al10 O35 phosphor exhibit characterization of Eu3+ emission bands that are located at a maximum wavelength (λmax ) of approximately 470 nm and other peaks centred at 593 nm and 615 nm, respectively. With Tb3+ -doped Ca14 Zn6 Al10 O35 phosphor showing a green emission band centred at 544 nm under near-ultraviolet range. Furthermore, we studied the energy transfer process in Eu3+ /Tb3+ pair and enhancement in photoluminescence (PL) intensity with doping different charge compensation. Here we obtained the optimum PL emission intensity of the phosphor in broad and intense visible spectral range which may be significant for the fabrication of white light emitting diodes (WLEDs).
Subject(s)
Europium , Luminescence , Europium/chemistry , Energy Transfer , X-Ray Diffraction , ZincABSTRACT
Borochlorate phosphors have shown their worth in modern day lighting over the last few years. Colour tunability of the phosphor is a modern techniques used to obtain white-light-emitting diodes (WLEDs). In the proposed work, Sm3+ ,Eu2+ -activated/co-activated Ba2 AlB4 O7 Cl phosphors were investigated for WLED applications as well as display devices. A convectional solid-state diffusion method was used to synthesize the proposed phosphors. X-ray diffraction (XRD) of the proposed phosphors confirmed the crystalline nature of the sample. Morphological studies on the samples were carried out using scanning electron microscopy analysis. A photoluminescence study of the colour tunable phosphor showed the characteristic peak of Sm3+ together with one broad peak for Eu2+ ions. Red to blue colour tunability was observed in the proposed phosphor with enhancement of Eu2+ ions. All these results showed the worth of this sample in WLED applications as well as in display devices.
Subject(s)
Europium , Luminescence , Europium/chemistry , X-Ray Diffraction , Microscopy, Electron, Scanning , LightingABSTRACT
Aluminate-based phosphors have been the most investigated luminescent phosphors over decades due to their outstanding optical properties. In the proposed work, a series of Sm3+ -doped Ca8.25 Na1.5 Al6 O18 (CNAO) phosphor sample was prepared using a simple combustion technique with the help of two fuels i.e., urea-glycine. The purity of phase and structural analysis of the CNAO phosphors were confirmed using X-ray diffraction analysis. Vibrational features of this phosphors confirmed were via Fourier transform infrared analysis. A photoluminescence study of this phosphor showed a doublet emission at 568 and 576 nm in the yellow region attributable to the 4 G5/2 â6 H5/2 transition of Sm3+ ions, whereas a doublet peak noticed in red region ranged from 600 to 620 nm and was attributable to the 4 G5/2 â6 H7/2 transition of Sm3+ ions. Moreover, Commission Internationale de l'éclairage colour coordinates were also located in the yellowish-red region and confirmed the potential of this phosphor as a yellowish-red component for white light-emitting diodes and display devices applications.
ABSTRACT
Pyrochlore phosphors have shown their worth in modern day lighting in the last few years. Colour tunability of the phosphor is one of the modern techniques used to obtain white light-emitting diodes (WLEDs). In the proposed work, Y2 Zr2 O7 :Sm3+ ,Eu3+ phosphors were investigated for WLED applications as well as display devices. A convectional solid-state diffusion method was used to synthesize the proposed phosphors. X-ray diffraction of the proposed phosphors was performed and compared with the standard Inorganic Crystal Structure Database. The crystal structure of the sample was cubic in nature, obtained from Rietveld refinement. Vibrational and morphological studies on the samples were carried out using Fourier transform infrared spectroscopy and scanning electron microscopy analysis. The photoluminescence study of the colour tunable phosphor showed the characteristic peak of Sm3+ together with the two sharp peaks of Eu3+ ions. Greenish yellow to red colour tunability was observed in the proposed phosphor with enhancement of Eu3+ ions. All these results showed the worth of this sample for WLEDs applications as well as in display devices.
ABSTRACT
Mineral fluorite or fluorspar (CaF2 ) can host significant quantities of trivalent REE3+ (rare earth element) by substitution with divalent Ca2+ . The fluorites associated with carbonatites are often REE-rich compared to those derived from sedimentary, hydrothermal, or Mississippi Valley-type (MVT) fluorites. The naturally occurring fluorites have several industrial applications one of which is for luminescence. Whether or not REE enriched, the fluorite makes an ideal host for REEs, which are very important phosphors. The naturally occurring fluorites are available in sufficient quantities to cater to the industrial demand. Investigations have been carried out on the fluorites from active fluorite mines at Dongargaon in central India. Thermoluminescence behavior of a natural fluorite sample was investigated using a Nucleonix TL 1009I thermoluminescence reader. Multiple traps formed in the broad thermoluminescent (TL) glow curve were found by TL anal deconvolution software. Trapping parameters for all multiple traps formed on deconvoluting broad TL glow curve were found by different methods like Initial rise method, Chen's Peak shape method and Ilich method.
Subject(s)
Luminescence , Luminescent Measurements , India , Thermoluminescent Dosimetry , X-Ray DiffractionABSTRACT
Dosimetry is a technique that quantitatively measures the ionizing radiation absorbed by matter. The present study was conducted on the barites from a mine at Dongargaon in Central India. Morphological and structural analysis of proposed sample was carried out using X-ray diffraction and standard error of the mean. Thermal analysis and chemical composition of the proposed sample were carried out using thermogravimetric analysis and differential thermal analysis, and electron probe microanalysis. Thermoluminescence (TL) studies on a natural barite sample were performed using a Nucleonix TL1009I TL reader following sample irradiation with γ-rays generated from a 60 Co irradiation source. A broad TL glow curve was observed after TL study that was then deconvoluted using TLanal deconvolution software. Trapping parameters from the sample such as activation energy (E), order of kinetics (b), and frequency factor (s) were calculated using Chen's peak shape method, the initial rise method, and Ilich's method. The results indicated that the natural barite sample could be used in high-dose TL dosimetric applications in various fields.
Subject(s)
Barium Sulfate , Luminescent Measurements , Gamma Rays , India , Thermoluminescent Dosimetry , X-Ray DiffractionABSTRACT
In this work, RE3+ (Eu, Ce and Sm)-activated Ca10 (PO4 )6 F2 (fluorapatite) phosphors were synthesized by doping with different apatite minerals (SO4 , VO4, WO4 ) using a solid-state diffusion method. Optical and structural characterizations were performed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy, and photoluminescence (PL) spectroscopy. XRD characterization showed the crystalline nature of the phosphor. PL properties were investigated under ultraviolet light excitation for all three rare earths. CIE chromaticity revealed the colour emitted in the visible region. Luminescence intensity was enhanced considerably by tuning the host matrices after core-shell formation by substitution with other ions producing promising candidates for white light-emitting diode materials.
