Synthesis and PL study of UV emitting phosphor KCa4(BO3)3:Pb2+ (original) (raw)
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Journal of Luminescence, 2019
Potassium calcium borate doped with dysprosium was synthesized by solid state diffusion method. Phase determination and compound confirmation were done by x-ray diffraction (XRD). Crystallite size calculated using Scherrer's formula was found to be around 117 nm. Other characteristics were studied using techniques like field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR). Band gap of the material was determined using ultraviolet-visible diffuse reflectance spectroscopy (UV-VIS DRS). The phosphor KCaBO 3 :Dy was irradiated by photon beams (of 1.25 MeV gamma and 4.88 eV UV rays) and ion beams (of 65 MeV and 85 MeV of O 6+ and 75 MeV of C 6+) with different doses in order to study its thermoluminescence (TL) properties. The phosphor showed good TL sensitivity towards these ionizing radiations. A good linear dose response was also shown by the phosphor for photon beam exposure. However, in case of ion beams exposure, dose response of the phosphor was good only for low energy oxygen ion beam. Also the phosphor showed good photoluminescence (PL) property with sharp peaks present in the PL emission and excitation spectra corresponding to the characteristic peaks of the dopant Dy. The Commission International de l'E clairage (CIE) was also used to calculate chromaticity coordinates and color temperature in order to investigate the phosphor's application in white LEDs. All these good characteristics make this phosphor a suitable candidate for radiation dosimetry and solid state lighting.
Synthesis and photoluminescence of inorganic borate host red emitting VUV phosphor YCaBO4:Eu[sup 3+]
2013
The red emitting borate host phosphor YCaBO4: Eu3+ has been prepared by a novel solution combustion technique. The synthesis is based on the exothermic reaction between the fuel (Urea) and Oxidizer (Ammonium nitrate). The photoluminescence properties of the powder samples of YCaBO4: Eu3+ has been investigated under UV and VUV excitation. The phosphor shows strong absorption in UV and VUV region and exhibits intense red emission upon excited by 254 nm UV and 173 nm VUV radiation. Under UV 254 nm excitation, YCaBO4: Eu3+ exhibits intense red emission around 610 nm. Under VUV excitation of 173 nm, the phosphor emits intense red emission around 610 nm and few weak emissions. These weak emissions could be suppressed by annealing the sample repeatedly at proper temperature and the borate phosphor YCaBO4: Eu3+ could be a good red emitting phosphor for PDP display and mercury free lamps.
Journal of Alloys and Compounds, 2014
The inorganic Oxy-borate host phosphors YCa 4 O(BO 3) 3 :RE 3+ (RE = Eu 3+ ,Tb 3+) were synthesized by a novel solution combustion technique. The synthesis is based on the exothermic reaction between the fuel (Urea) and Oxidizer (Ammonium nitrate). The heat generated in reaction is use for auto combustion of precursors. The structures of the prepared samples were confirmed by powder XRD technique. The photoluminescence properties of the powder samples were investigated under UV and VUV excitation; ''The phosphor YCa 4 O(BO 3) 3 :Eu 3+ and YCa 4 O(BO 3) 3 :Tb 3+ shows strong absorption in UV and VUV region and exhibits intense red and green emission upon excited by 254 nm UV and 147 nm VUV radiation''.
Journal of Luminescence, 2019
A highly efficient solution combustion technique involving simple procedure and less energy consumption was adopted to prepare a homogeneous crystalline Ba 3 Y 4 O 9 :Sm 3þ down-conversion nanophosphor emitting bright reddish orange light. The structural features of the synthesized nanophosphors were characterized by powder Xray diffraction (PXRD), scanning electron microscope (SEM), transmission electron microscope (TEM), high resolution transmission electron microscope (HRTEM), selected area energy diffraction (SAED) and energydispersive X-ray analysis (EDAX) techniques. Moreover, the photoluminescent features of the nanocrystalline phosphors were described by photoluminescence decay curves, excitation and emission spectra. Upon nearultraviolet (NUV) excitation (410 nm), the emission spectra demonstrate the most prominent peak at 607 nm due to 4 G 5/2 → 6 H 7/2 transition. The optimum mol% of dopant (Sm 3þ) ion for doping in this particular host matrix was found to be 3; thus, a concentration quenching (CQ) phenomenon was observed beyond x ¼ 0.03 in the synthesized Ba 3 Y 4(1-x) O 9 : 4x Sm 3þ nanophosphors. The most appropriate reason for CQ mechanism was reckoned to be radiative-reabsorption phenomenon and dipole-dipole (d-d) interactions. The CIE chromaticity coordinates for the optimum nanophosphor were found to lie in orange-red region that confirm its characteristic light emission. The results indicate the promising applications of the synthesized reddish-orange light emitting Ba 3 Y 4 O 9 : Sm 3þ nanophosphor in white light emitting diodes (WLEDs).
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.
Combustion synthesis of borate phosphors
Optical Materials, 2007
A fast and simple method of preparation, based on the combustion synthesis, is described for the synthesis of borate based PL phosphors which can be used for commercial lamp applications. Phosphors with various structures, incorporating different activators could be successfully prepared. PL intensities of (Gd0.6Ce0.2Tb0.2)MgB5O10, SrB4O7:Eu2+ and La0.88Gd0.1Bi0.02B3O6 were found to be comparable with those of the corresponding commercial phosphors.
A novel UV-emitting phosphor: Li6CaB3O8.5:Pb2+
Journal of Luminescence, 2011
Pure Li 6 CaB 3 O 8.5 and Li 6 Ca 1 À x Pb x B 3 O 8.5 (0.005 rx r 0.04) materials were prepared by a solution combustion synthesis method. The phase of synthesized materials was determined using the powder XRD and FTIR. The synthesized materials were investigated using spectrofluorometer at room temperature. The emission and excitation bands of the synthesized phosphors were observed at 307 and 268 nm, respectively. The dependence of the emission intensity on the Pb 2 þ concentration for the Li 6 Ca 1 À x Pb x B 3 O 8.5 (0.005 rx r0.04) was studied and observed that the optimum concentration of Pb 2 þ in phosphor is 0.01 mol. The Stokes shift of the synthesized phosphor was calculated to be 4740 cm-1 .
A potential red emitting K4Ca(PO4)2: Eu3+ phosphor for white light emitting diodes
Journal of Luminescence, 2012
Europium (III) ions doped red phosphors K 4 Ca(PO 4) 2 were prepared first time by high temperature solid state reaction method. The prepared phosphors structure was examined by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) analyses. The thermal properties of the synthesized phosphor were investigated by differential scanning calorimetry (DSC) analysis. Photoluminescence (PL) spectra of K 4 Ca(PO 4) 2 :Eu 3 þ phosphors have shown strong red emission at 618 nm (5 D 0-7 F 2) with near UV an excitation wavelength of l exc ¼ 394 nm (7 F 0-5 L 6). In addition, the decay curves and CIE color coordinate measurements are also carried out. Hence, emission and excitation characterization of synthesized phosphors shows that the phosphors may be a promising red component for the application in the white light emitting diodes (WLEDs).
Optik, 2016
In this paper we report the photoluminescence (PL) characteristics of Dy 3+ , Sm 3+ , Eu 3+ and Tb 3+ doped Na 3 Pb 2 (SO 4) 3 Cl phosphors prepared by wet chemical method. Prepared phosphors were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), color coordinates and photoluminescence (PL) properties. The emission spectra of Na 3 Pb 2 (SO 4) 3 Cl:Dy 3+ phosphor show the characteristic emission of Dy 3+ ions peaking at 478 nm and 573 nm (ex = 390 nm), owing to transitions of 4 F 9/2 → 6 H 15/2 and 4 F 9/2 → 6 H 13/2 receptively. Under 396 nm excitation the Na 3 Pb 2 (SO 4) 3 Cl:Eu 3+ phosphor shows emission at 594 nm and 616 nm due to 5 D 0 → 7 F 1 and 5 D 0 → 7 F 2 transitions of Eu 3+ ions respectively. When Na 3 Pb 2 (SO 4) 3 Cl:Tb 3+ phosphor was excited by 380 nm, the emission spectrum showed intense green band at 545 nm due to 5 D 4 → 7 F 5 transition in Tb 3+ ion. The PL emission spectrum of Na 3 Pb 2 (SO 4) 3 Cl:Sm 3+ phosphors by 405 nm excitation gave an emission at 562 nm (4 G 5/2 → 6 H 5/2), 598 nm (4 G 5/2 → 6 H 7/2) and 643 nm (4 G 5/2 → 6 H 9/2). The CIE color coordinates indicated that all the above phosphors were suitable as a white light-emitting phosphor. SEM studies of the phosphors show that grain size of the powders prepared by the wet chemical method is about ten micrometers range. From the obtained results it can be concluded that Dy 3+ , Sm 3+ Eu 3+ and Tb 3+ doped Na 3 Pb 2 (SO 4) 3 Cl phosphors are potential candidates for solid state lighting applications in green technology.