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Dhoble N.S.,Sevadal Mahila Mahavidyalaya | Pawade V.B.,VNIET | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Advanced Materials Letters | Year: 2011

Eu2+ luminescence in novel Sr3.5Mg0.5Si3O8Cl4 and Ba3.5Mg0.5Si3O8Cl4 phosphors is reported in this paper. These were synthesized by combustion method at 5500C furnace temperature .The prepared phosphors shows PL emission spectra at 445 nm ,due to 4f65d1→4f7 transition of Eu2+ ions by monitoring excitation at 358 nm for Sr and Ba host lattice. Phase purity was checked by using XRD-pattern. The prepared phosphors have potential applications for solid-state lighting purpose. © 2011 VBRI press.


Pawade V.B.,VNIET | Dhoble N.S.,Sevadal Mahila Mahavidyalaya | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Solid State Sciences | Year: 2012

Novel Eu 2+ and Ce 3+ activated BaMg 8Al 18Si 18O 72 phosphors was prepared by combustion method and their PL characteristics were investigated. The result shows that all samples can be excited efficiently by near UV excitation under 334 nm and 316 nm. The emission was observed for BaMg 8Al 18Si 18O 72:Eu 2+ phosphor at 437 nm corresponding to d → f transition, under 334 nm broad-band excitation, whereas BaMg 8Al 18Si 18O 72:Ce 3+ phosphor shows emission band at 376 nm under 316 nm excitation. Phase purity of the phosphor was checked with the help of XRD pattern. SEM analysis shows the external morphology of the combustion synthesized phosphor. © 2011 Elsevier Masson SAS. All rights reserved.


Pawade V.B.,VNIET | Dhoble N.S.,Sevadal Mahila Mahavidyalaya | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Journal of Luminescence | Year: 2012

In this article, we have reported emission characteristics of Eu 2+ activated Sr 12Al 10.6Si 3.4O 32Cl 5.4 and Ca 12Al 10.6Si 3.4O 32Cl 5.4 phosphors, prepared by combustion synthesis. The PL excitation was monitored at two different wavelengths 254 nm (mercury excitation) and 354 nm (mercury free excitation), which shows broad-blue emission bands at 432 nm, and 438 nm for 354 nm excitation wavelength. Under mercury excitation at 254 nm it shows emission wavelengths at 470 nm, 589 nm, 592 nm, and 617 nm for the prepared Sr 12Al 10.6Si 3.4O 32Cl 5.4 and Ca 12Al 10.6Si 3.4O 32Cl 5.4 phosphors. Further it was characterized by XRD, for the investigation of phase and purity of the phosphors. Thermal degradation of the phosphors was also studied at different temperatures. © 2012 Elsevier B.V. All rights reserved.


Kore B.P.,Rashtrasant Tukadoji Maharaj Nagpur University | Dhoble N.S.,Sevadal Mahila Mahavidyalaya | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Journal of Luminescence | Year: 2014

Dy doped Na21Mg(SO4)10Cl3 phosphor was prepared by modifying the solid state method and the formation of the compound was confirmed by X-ray diffraction (XRD) study. Morphology of the phosphor was analyzed by scanning electron microscopy (SEM). The thermally stimulated luminescence (TSL) studies of Dy doped Na21Mg(SO 4)10Cl3 samples show the complex glow curve. Powder samples of Na21Mg(SO4)10Cl 3:Dy were irradiated by 2.2 MeV β-particles within dose range of 100-16,000 mGy. Analysis of the thermoluminescence glow curves was carried out by Tm-Tstop and glow curve deconvolution (GCD) method. Trapping parameters (activation energy and frequency factor) for individual deconvoluted peaks were obtained by Chen's peak shape method. The comparison of trapping parameters between γ-ray irradiated and β-particles irradiated Na21Mg(SO4)10Cl3:Dy phosphor were also studied. © 2013 Elsevier B.V.


Kore B.P.,Rashtrasant Tukadoji Maharaj Nagpur University | Dhoble N.S.,Sevadal Mahila Mahavidyalaya | Lochab S.P.,Inter University Accelerator Center | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Journal of Luminescence | Year: 2014

Photoluminescence and thermoluminescence properties of KCaSO4Cl doped with dysprosium and cerium have been studied. Dy/Ce doped KCaSO 4Cl phosphors were synthesized by the acid distillation method. The samples were characterized by XRD, SEM, PL and TL for structural, morphological and luminescence studies. The SEM image analysis of KCaSO4Cl phosphor shows nearly spherical particles with diameter varying between 3-10 μm. In the present host Dy3+ emission at 482 and 573 nm is observed due to 4F9/2→6H15/2 and 4F9/2→6H13/2 transition, respectively, whereas the PL emission spectra of KCaSO4Cl:Ce phosphor shows two luminescence bands at 307 nm and 326 nm and are attributed to the allowed inter configurational transitions from the 5d-level to the 2F5/2 and 2F7/2 levels of Ce 3+ ion. Effect of annealing on the structure of the glow curve is investigated for KCaSO4Cl:Dy phosphors. Thermoluminescence linearity has been studied for 0.1-9000 Gy dose of gamma rays. Linear behavior over a large dose range between 0.1 Gy and 170 Gy was found. In addition to this trap parameters of KCaSO4Cl:Dy were studied using computerized glow curve deconvolution. © 2013 Elsevier B.V. All rights reserved.


Kore B.P.,Rashtrasant Tukadoji Maharaj Nagpur University | Dhoble N.S.,Sevadal Mahila Mahavidyalaya | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Journal of Luminescence | Year: 2014

The photoluminescence (PL) and thermoluminescence (TL) properties of BaAl2O4:Eu2+ phosphor synthesized by the combustion method is studied. Electron beam and gamma rays are used for irradiating the phosphor while performing TL measurements. The structural and morphological analysis of the resulting phosphor was carried out by X-ray diffraction study and scanning electron microscopy, whereas their optical properties were examined by PL spectroscopy and TL glow curve measurements. The intense bluish green broad band emission near 494 nm that originates from 5d to 4f transition in Eu2+ ions was observed in the BaAl2O 4:Eu2+ phosphor. The broad band emission was further examined, showing that emission consist of two broad peaks originating due to occupation of two different lattice sites by Eu in BaAl2O4 host. The occurrence of two broad bands with large stokes shift and hence anomalous emission is explained by proposing energy level model. Calculations based on Dorenbos formulations were carried out which support the presence of anomalous emission in BaAl2O4:Eu2+ phosphor. The TL response of BaAl2O4:Eu2+ phosphor for two different radiations was compared and studied in detail. Detailed process and possible mechanisms for PL and TL are studied and discussed with the help of energy level models. © 2014 Elsevier B.V.


Raut S.K.,Rashtrasant Tukadoji Maharaj Nagpur University | Dhoble N.S.,Sevadal Mahila Mahavidyalaya | Park K.,Sejong University | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Materials Chemistry and Physics | Year: 2014

A series of new phosphors of BaCa2Si3O 9:Ln3+, (Ln = Eu, Ce, Dy, Sm, Tb) were synthesized by precipitation based method. Good crystallinity was achieved after annealing the sample at 750 °C for 1 h in air. X-ray powder diffraction (XRD) result confirmed the formation of desired BaCa2Si3O9 host. The photoluminescent excitation and emission properties of Ln 3+, (Ln = Eu, Ce, Dy, Sm, Tb) activated BaCa2Si 3O9 were investigated in detail. The photoluminescence (PL) analysis of individual Ln3+, (Ln = Eu, Ce, Dy, Sm, Tb) activated BaCa2Si3O9 phosphors exhibits interesting characteristic emission properties in their respective regions. From the measured emission spectra, Judd-Ofelt (J-O) intensity parameters (Ω2, Ω4, Ω6) have been calculated and using these J-O parameters various radiative parameters such as radiative transition probabilities (Arad), radiative lifetimes (τR), branching ratios (βR) and relative quantum yield have been calculated for the studied ions. © 2014 Elsevier B.V. All rights reserved.


Kore B.P.,Rashtrasant Tukadoji Maharaj Nagpur University | Dhoble N.S.,Sevadal Mahila Mahavidyalaya | Lochab S.P.,Inter University Accelerator Center | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
RSC Advances | Year: 2014

Dy3+-doped CaMg3(SO4)4 (CMS) phosphor was prepared by the acid distillation method and examined in detail with a thermoluminescence (TL) study whereby the phosphor was irradiated with γ-rays and a carbon ion beam. A good dosimetric glow curve was observed that is stable against both types of radiation. The CMS doped with 0.2 mol% of Dy3+ showed 3.5 times more sensitivity than commercially available CaSO4:Dy3+ TLD phosphor when irradiated with a carbon ion beam. The observed glow curve variation and resultant variation in the values of trapping parameters with a change in ion beam energy suggest more complex interactions of ion beam within the phosphor at higher energies. © the Partner Organisations 2014.


Kore B.P.,Rashtrasant Tukadoji Maharaj Nagpur University | Dhoble N.S.,Sevadal Mahila Mahavidyalaya | Park K.,Sejong University | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Journal of Luminescence | Year: 2013

In the present work luminescence properties of rare earth (RE) doped Na21Mg(SO4)10Cl3 were studied. Modified solid state method was employed to synthesize the phosphors. The influence of RE (RE=Dy and Eu) doping on the luminescence properties of as prepared phosphor were investigated in detail. PL emission spectra of the Na21Mg(SO4)10Cl3:Dy phosphor exhibits the characteristic emission of Dy. The characteristic Dy3+ emission in the form of peaks around 482 and 576 nm corresponding to transitions 4F9/2→6H15/2 and 4F9/2→6H13/2 was seen when excited by excitation wavelength 351 nm. However, interesting thermoluminescence results are observed in case of Dy as well as Eu doped Na 21Mg(SO4)10Cl3. The TL glow curves for Na21Mg(SO4)10Cl3:Dy exhibit broad peak composed of three overlapping peaks, these peaks were deconvoluted using deconvolution program. The peaks at different temperatures indicate that different sets of traps are being activated within the particular temperature range each with its own value of activation energy (E) and frequency factor (s). The peaks observed were due to formation of trap levels by γ-rays irradiation and subsequently activation of traps on thermal stimulation. The trapping parameters for both the samples were calculated using Chen's peak shape method and reported in this paper. © 2013 Elsevier B.V.


Kore B.P.,Rashtrasant Tukadoji Maharaj Nagpur University | Dhoble N.S.,Sevadal Mahila Mahavidyalaya | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Radiation Measurements | Year: 2014

Thermoluminescence (TL) properties of sulfate-based phosphors activated by different rare earths have received tremendous attention to the field of radiation dosimetry. Those TL materials based on CaSO4 have been widely applied for medical and environmental dosimetry. Taking this fact into account we have synthesized Na6Mg(SO4)4 doped with Ce and Tb by wet chemical method. The prepared phosphor was characterized by XRD, FTIR, photoluminescence (PL) and thermoluminescence. For TL study, the phosphor is irradiated with γ-rays from 60Co source. For studying luminescence properties, the prepared phosphor was annealed at different temperatures and effects of these annealing temperatures on Na 6Mg(SO4)4 samples are investigated and quantified. The changes in the glow curve and PL emission spectrum are also investigated as a function of annealing temperature and the annealing temperature was optimized. For calculation of trapping parameters various methods such as peak shape (PS) method, initial rise (IR) method, various heating rate (VHR) method, and computerized glow curve deconvolution (CGCD) are employed. © 2014 Elsevier Ltd. All rights reserved.

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