Bramhapuri, India
Bramhapuri, India

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Akojwar A.,Ns Science And Arts College | Shinde K.N.,Ns Science And Arts College | Kokode N.S.,Nh College
Results in Physics | Year: 2017

Red-emitting phosphor KAl1-xPO4F:Eux 3+ (0.1 ≤ x ≤ 1.0) were fabricated by combustion process at temperature 750 °C. The XRD patterns did not indicate presence of the starting constituents and other likely phases which are an indirect evidence for the formation of the desired compound. The photoluminescence study shows that the intensity of electric dipole transition (5D0 → 7F2) at 613 nm dominates over that of magnetic dipole transition (5D0 → 7F1) at 595 nm. The FTIR also shows peaks appearing at 585.41–827.92 cm−1 and 912.99–1074.12 cm−1 correspond to the bending vibrations (v4 region) and stretching vibrations (v3 region) of PO43− group, respectively. The chromaticity coordinate of KAlPO4F:Eu3+ phosphor (x = 0.674, y = 0.325) is much closer to National Television Standard Committee (NTSC) standard value for red phosphor (x = 0.670, y = 0.330). All the spectrum features indicate that KAlPO4F:Eu3+ might be a promising phosphor for lighting or w-LEDs. © 2017 The Author(s)

Baig N.,Janata Mahavidhyalaya | Dhoble N.S.,Sevadal Mahila Mahavidyalaya | Park K.,Sejong University | Kokode N.S.,Nh College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Luminescence | Year: 2015

The luminescent properties of europium (Eu)- and dysprosium (Dy)-co-doped K3Ca2(SO4)3Cl halosulfate phosphors were analyzed. This paper reports the photoluminescence (PL) properties of K3Ca2(SO4)3Cl microphosphor doped with Eu and Dy and synthesized using a cost-effective wet chemical method. The phosphors were characterized by X-ray diffraction and scanning electron microscopy. The CIE coordinates were calculated to display the color of the phosphor. PL emission of the prepared samples show peaks at 484 nm (blue), 575 nm (yellow), 594 nm (orange) and 617 nm (red). The emission color of the Eu,Dy-co-doped K3Ca2(SO4)3Cl halophosphor depends on the doping concentration and excitation wavelength. The addition of Eu in K3Ca2(SO4)3Cl:Dy greatly enhances the intensity of the blue and yellow peaks, which corresponds to the 4 F9/2 → 6H15/2 and 4 F9/2 → 6H13/2 transitions of Dy3+ ions (under 351 nm excitation). The Eu3+/Dy3+ co-doping also produces white light emission for 1 mol% of Eu3+, 1 mol% of Dy3+ in the K3Ca2(SO4)3Cl lattice under 396 nm excitation, for which the calculated chromaticity coordinates are (0.35, 0.31). Thus, K3Ca2(SO4)3Cl co-doped with Eu/Dy is a suitable candidate for NUV based white light-emitting phosphors technology. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

Panse V.R.,Gondwana University | Kokode N.S.,Nh College | Yerpude A.N.,Nh College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Optik | Year: 2016

Terbium doped Sr2B2O5 green phosphor was synthesized by combustion synthesis method at about 550 °C. Further, analyzed by XRD technique and XRD pattern of prepared phosphor is well match with standard JCPDs file. The morphology and structure of the phosphor were characterized by scanning electron microscopy. The chromatic coordinates estimated from emission spectra shown by CIE chromatic diagram and values observed are Cx = 0.263, Cy = 0.723. The vibrational characteristics were studied with the help of FTIR. The excitation and emission spectra specify that the prepared phosphor can be effectively excited by 353 nm and reveal bright green emission centered at 545 nm consequent to the D → F transition of Tb3+ ion. From the obtained results it is concluded that present phosphor may be efficient photoluminescent materials for solid-state lighting and energy saving applications. © 2015 Elsevier GmbH.

Panse V.R.,NCET | Kokode N.S.,Nh College | Shukla A.,NIT | Yerpude A.N.,Nh College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Optik | Year: 2016

In this paper we report the combustion synthesis of trivalent rare-earth (RE3+ = Tb and Eu) activated Ca2BO3Cl phosphor. The prepared phosphors were characterized by the X-ray powder diffraction (XRD) and CIE and PL and TL techniques. Photoluminescence emission peaks of Ca2BO3Cl:Tb3+ phosphor at 546 nm in the green region of the spectrum excited by 352 nm. The prepared Eu3+ doped phosphors were excited by 396 nm then we found that the characteristics emission of europium ions at 594 nm (5D0 → 7F1) and 620 nm (5D0 → 7F2). The chromaticity coordinates for the prepared compound is found to be Cx = 0.272, Cy = 0.716 for Tb3+ and Cx = 0.592, Cy = 0.406, Cx = 0.686, Cy = 0.307 for Eu3+ ions estimated from the emission spectra of prepared sample with both activators. In present study the trapping parameters such as order of kinetics(b), activation energy(E) and frequency factors(s) have been calculated for the glow peaks of Ca2BO3Cl:Tb3+ by using Chen's method. © 2016 Published by Elsevier GmbH.

Panse V.R.,NCET | Yerpude A.N.,Nh College | Kokode N.S.,Nh College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Optik | Year: 2016

In this paper we report the synthesis of Sr2BO3Cl:Dy3+ phosphor prepared by modified solid state method. X-ray powder diffraction (XRD) and Photoluminescence (PL) were carried out. The absorption band located at 351 nm is a main excitation peak matching with the emission of near-ultraviolet light (340-400 nm). The emission spectrum consists mainly of two groups of line, which are situated around 485 nm (blue emission) and 576 nm (yellow emission). These line can be assigned to the transitions 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2, respectively. The concentration quenching effect for Dy3+ was found at the optimum doping concentration of 1 mol%. The prepared phosphor may be useful for eco-friendly lighting technology. © 2016 Elsevier GmbH. All rights reserved.

Akojwar A.,Ns Science And Arts College | Shinde K.N.,Ns Science And Arts College | Singh R.,Rashtrasant Tukadoji Maharaj Nagpur University | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University | Kokode N.S.,Nh College
Luminescence | Year: 2016

A series of phosphors KAl1-xPO4Cl:Eux 3+ (0.1 ≤ x ≤ 1.0) was synthesized using a facile combustion method using urea as a fuel and their structural, morphological and photoluminescence properties were investigated. It was found that the particle size was in the range of 1-2 μm with an irregular shape. The f-f transitions of Eu3+ in the host lattice were assigned and discussed. The excitation and emission spectra indicated that this phosphor can be efficiently excited by ultraviolet (395 nm), and exhibit reddish orange emission corresponding to the 5D0→7FJ (J = 0, 1, 2) transitions of Eu3+. The impact of the Eu3+ concentration on the relative emission intensity was investigated, and the best doping concentration is 0.5. The present study suggests that the KAl0.5PO4Cl: Eu0.5 3+ phosphor is a strong candidate as a red component for phosphor- converted white light-emitting diodes (LEDs). Copyright © 2015 John Wiley & Sons, Ltd.

Yerpude A.N.,Nh College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Optik | Year: 2016

Green emitting SrAl4O7:Eu2+, SrAl4O7:Eu2+, Dy3+, SrAl4O7:Eu2+, Dy3+, Ce3+ phosphors were synthesize by combustion method. The phosphor samples were well characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Photoluminescence(PL) emission and excitation spectra, Fourier transform infrared (FTIR) study, luminescence decay and afterglow decay. The excitation and emission spectra indicates that the phosphor could be well excited by UV light and give broad band emission due to the 4f65d → 4f7 transition of Eu2+ ions. All the phosphors show green long lasting phosphorescence phenomena after the excitation source was removed. The SrAl4O7:Eu2+, Dy3+, Ce3+ phosphor has longest afterglow comparably than SrAl4O7:Eu2+ and SrAl4O7:Eu2+, Dy3+ phosphors. The SrAl4O7:Eu2+, Dy3+ phosphor exhibits one thermally stimulated luminescence (TSL) peak at 90 °C and SrAl4O7:Eu2+, Dy3+, Ce3+ phosphor exhibits peak at 99°C. The luminescence decay curves are well fitted with double exponential equation. Scanning electron microscopy (SEM) study was carried out to investigate the surface morphology and the crystallite sizes. © 2016 Elsevier GmbH. All rights reserved.

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