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Nāgpur, India

Poddar A.,Sindhu Mahavidyalaya | Gedam S.C.,Kzs Science College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Journal of Luminescence | Year: 2014

The phosphors prepared by wet chemical method are studied for their photoluminescence (PL) and thermoluminescence (TL) characteristics. The paper discuses the results on KMgSO4F:Ce halosulfate phosphor co-doped with trivalent rare-earths Dy or Eu which improved luminescence properties. The Dy3+ emission is peaking at 480 nm and 576 nm for an excitation of 390 nm due to 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions in blue and yellow-orange region of visible range, whereas Eu3+ is at 590 nm and 612 nm (orange and red region) due to 5D 0→7F1 and 5D 0→7F2 transitions of Eu3+ ion. TL glow curves of KMgSO4F pure, KMgSO4F:Dy, KMgSO 4F:Eu show single peaking at around 154 C, 172 C 180 C, respectively. TL glow curves of KMgSO4F:Ce, Dy show two peaks at the temperatures 202 C and 370 C, whereas KMgSO4F:Ce,Eu shows single peak which is located at around 198 C when they exposed to γ-rays for 5 Gy at the rate of 0.36 kGy h-1. © 2014 Elsevier B.V. Source


Poddar A.,Sindhu Mahavidyalaya | Gedam S.C.,Kzs Science College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Journal of Luminescence | Year: 2015

The present KMgCl3 phosphor has been synthesized through wet chemical synthesis (WCS), solid state diffusion (SSD) and Hispersed centrifuge (HC) routes in the same atmospheric conditions and characterized for luminescence properties. XRDs of the sample prepared by all three methods have been placed at the same position, phase and matched well with standard data. The particle size of 20 nm of KMgCl3 by a Hispersed centrifuged method was detected using a transmission electron microscope (TEM). The PL emission spectra have been observed for Ce3+ at 353 nm and 375 nm due to 5d→4f transition, whereas luminescence of Dy3+ efficiently observed at 484 nm and 579 nm for an excitation of 384 nm due to 4F9/2→ 6H15/2 and 6H13/2 (blue-yellow region) transition and Eu3+ is peaking at 596 nm and 616 nm (λex=394 nm) due to level 5D0 to 7Fj (j=0, 1, 2, and 3) radiative transitions. The presented phosphors are excited in the range of 300-400 nm which is mercury free excited range. Synthesis and photoluminescence spectra of trivalent Ce, Dy or Eu rare-earths in KMgCl3 are described for all three routes, for the first time in the present work. The CIE chromaticity coordinates were also calculated for KMgCl3:X (Ce3+, Dy3+ and Eu3+) phosphors, which are close to the NTSC standard values. KMgCl3 matrix is not only suitable for different and easy synthesis but efficient luminescence also. The paper discuses the XRD, crystallinity (morphology) and luminescence of Ce, Dy or Eu rare-earths in KMgCl3 synthesized by three (WCS, SSD and HC) different routes. © 2014 Elsevier B.V. All rights reserved. Source


Gedam S.C.,Kzs Science College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University | Park K.,Sejong University
Journal of Luminescence | Year: 2013

Newly prepared NaZnSO4Cl chlorosulphate material investigated by a wet chemical method was confirmed by the X-ray powder diffraction (XRD) pattern. Photoluminescence (PL) of NaZnSO4Cl:Ce3+ shows strong emission at 330 nm, and it is also efficient for Ce3+→ Dy3+ and Ce3+→Mn2+ energy transfer for different concentrations. The Dy3+ emission by Ce3+→ Dy3+ under UV wavelength peaking at 473 nm and 573 nm for an excitation of 254 nm due to 4F9/2 →6H 15/2 and 6H13/2 transitions, whereas Ce 3+→Mn2+ is peaking at 515 nm due to 4T1→6A1 transitions. In this phosphor the energy transfer takes place via the resonant process which is dependent on the concentration of the ions. The purpose of the present study is to develop and understand the photoluminescence and effect of Dy3+ or Mn2+ co-doping in NaZnSO4Cl:Ce3+ luminescent material, which can be used as a lamp phosphor. © 2013 Elsevier B.V. Source


Gedam S.C.,Kzs Science College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Journal of Luminescence | Year: 2013

Polycrystalline KCaSO4Cl: (Ce, Dy, Mn and Pb) phosphors prepared by solid state diffusion method have been studied for its trapping parameters by thermoluminescence (TL) phenomenon. The TL glow curves of KCaSO 4Cl: (Ce, Dy, Mn and Pb) phosphor for different concentrations have been recorded at a heating rate of 2 C sec-1 and irradiated at a dose rate of 0.995 kGyh-1 for 5 Gy. The TL glow curves of γ-irradiated KCaSO4Cl: (Ce, Dy, Mn and Pb) phosphors show one glow peak indicating that only one set of traps is being activated within the particular temperature range each with its own value of activation energy (E) and frequency factor (s). The trapping parameters associated with the prominent glow peak of KCaSO4Cl: (Ce, Dy, Mn and Pb) is calculated by using Chen's half width method. The phosphors KCaSO4Cl: Ce, and Pb show first order kinetics while, Dy and Mn show the second order kinetics. The trap depth and frequency factors have been studied subsequently. The release of hole or electron from defect centers at the characteristic trap site initiates the luminescence process in this material. © 2013 Elsevier B.V. All rights reserved. Source


Gedam S.C.,Kzs Science College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Journal of Luminescence | Year: 2013

The thermoluminescence (TL) characteristics and effect of γ-radiation on newly invented NaZnSO4Cl:Ce, Dy or Mn ions and retrapping of charges in TL material prepared by wet chemical method are studied. The sensitivity of the NaZnSO4Cl:Ce, Dy or Mn phosphors is higher than that of CaSO4:Dy with the broadness of the glow peak for various concentrations of Ce, Dy, Mn and different γ-rays doses. The phosphor NaZnSO4Cl:Ce has remarkable high sensitivity as compared to NaZnSO4Cl:Dy or Mn. The phosphors NaZnSO4Cl:Ce, and Mn have a simple TL glow curve structure with a single prominent peak at around the temperature 170 and 190 C, whereas NaZnSO4Cl:Dy has two peaks located at 175 and 298 C indicating single and double trapping sites respectively. TL response, fading and reusability characteristics and the trapping parameters of the phosphor are also studied and it is found that the phosphor is quite suitable for use in dosimetry of ionizing radiations. © 2013 Elsevier B.V. Source

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