Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College

Durg, India

Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College

Durg, India
SEARCH FILTERS
Time filter
Source Type

Dubey V.,Bhilai Institute of Technology | Kaur J.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Agrawal S.,National Institute of Technology Raipur
Materials Science in Semiconductor Processing | Year: 2015

The present paper deals with the effect of europium (Eu3+) doping concentration (0.1-2.5 mol%) on photoluminescence (PL) and thermoluminescence (TL) of strontium yttrium oxide (SrY2O4) phosphor. The sample was prepared by the modified solid state reaction method, which is the most suitable method for large-scale production. The prepared phosphor sample was characterized by using X-ray Diffraction (XRD), field emission gun scanning electron microscopy, fourier transform infrared spectroscopy, high resolution transmission electron microscopy, photoluminescence, thermoluminescence and commission internationale de IEclairage techniques. The PL emission was observed in the range of 410-630 nm for the SrY2O4 phosphor doped with Eu3+. Excitation spectrum was found at 254 and 325 nm, sharp peaks were found around 593, 615 and 625 nm with high intensity. From the XRD data, using Scherrers formula, calculated average crystallite size of Eu3+ doped SrY2O4 phosphor is around 32 nm. Thermoluminescence study was carried out for the phosphor with UV and gamma irradiation. The TL response of SrY2O4:Eu3+ phosphor for two different radiations was compared and studied in detail. The present phosphor can act as a single host for white light emission in display devices. The detailed process and possible mechanisms for PL and TL are studied and discussed. For the variable concentration of Eu3+ on PL studies the PL intensity increases with increasing the concentration of dopant and the concentration quenching found after 2 mol% of Eu3+ the optimized concentration was 2 mol%, which is suitable for the display device application. In TL glow curve the optimized concentration was 1 mol% for the UV irradiated sample and 0.2 mol% of Eu3+ for the gamma irradiated sample and beta irradiated sample for 10 Gy dose. The kinetic parameters were calculated by the computerized glow curve deconvolution (CGCD) technique. © 2014 Elsevier Ltd. All rights reserved.


Dubey V.,National Institute of Technology Raipur | Kaur J.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Agrawal S.,National Institute of Technology Raipur
Research on Chemical Intermediates | Year: 2015

The present paper reports the synthesis, photoluminescence (PL), and thermoluminescence (TL) studies of Eu3+-doped yttrium oxide (Y2O3) phosphor using inorganic materials like Y2O3, flux calcium fluoride, and europium oxide. The sample was prepared by the modified solid state reaction method, which is the most suitable for large-scale production. The prepared phosphor sample was characterized using powder X-ray diffraction, field emission gun scanning electron microscopy, high resolution transmission electron microscopy, Fourier transform infrared spectroscopy, PL, TL, and Commission Internationale de I'Eclairage techniques. The PL emission was observed in the range 417-632 nm ranges all visible regions for the Y2O3 phosphor doped with Eu3+. Excitation spectrum found at 254 nm. Sharp intense peaks found around 467, 534, 594, 612, and 632 nm with high intensity. From the XRD data, using the Scherer's formula, the calculated average crystallite size of Eu3+-doped Y2O3 phosphor is around 45 nm. TL study was carried out for the phosphor with UV irradiation. The present phosphor can act as single host for white light emission in display devices. © 2014 Springer Science+Business Media Dordrecht.


Dubey V.,National Institute of Technology Raipur | Kaur J.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Agrawal S.,National Institute of Technology Raipur | Suryanarayana N.S.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Murthy K.V.R.,M. S. University of Baroda
Superlattices and Microstructures | Year: 2014

The present paper reports the synthesis, photoluminescence (PL) and thermoluminescence (TL) studies of Eu3+ doped YBO3 phosphor. The samples were prepared by the conventional solid state reaction method with different concentrations of Eu3+ ions, which is the most suitable method for large-scale production. The prepared phosphor sample was characterized using X-ray diffraction (XRD), Field Emission Gun Scanning Electron Microscopy (FEGSEM), high resolution transmission electron microscopy (HRTEM), Fourier Transform Infrared Spectroscopy (FTIR), photoluminescence (PL), thermoluminescence (TL) and CIE coordinate techniques. The PL emission was observed in the range 575-650 nm range for the YBO3 phosphor doped with Eu3+. Excitation spectrum found at 237, 254 and 395 nm. Sharp peaks found around 594, 612 and 628 nm with high intensity. From the XRD data, using the Scherer's formula the calculated average crystallite size of Eu 3+ doped YBO3 phosphor is around 201 nm. Thermoluminescence study was carried out for the phosphor with UV, beta and gamma irradiation. The present phosphor can act as single host for red-orange light emission in display devices. © 2014 Elsevier B.V. All rights reserved.


Kaur J.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Suryanarayana N.S.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Dubey V.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College
Chalcogenide Letters | Year: 2010

The present paper reports that the ML spectral distribution of Au doped (Zn, Cd) S mixed phosphors. The measurements were made at room temperature between 4000 3and 7000Å. The ML spectra was recorded on the oscilloscope using a series of filters with different transmission coefficients while the spectral emission curves of the sample were measured at room temperature, between 4000 Å and 7000Å on the Hitachi spectrometers using long wavelength ultraviolet excitation provided by 150 watt xenon lamp. Since the excitation process depend on mechanical deformation, which is slower than the absorption of photon, the rate of ML will be different from that of PL & EL. ML and PL are examined by comparing their energy relationship. The spectral distribution is found to be similar in ML and PL. Since the PL of phosphors is well known, it is expected that the comparative study of ML with PL will be helpful to understand the process of ML excitation in (Zn, Cd) S mixed phosphors.


Kaur J.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Suryanarayana N.S.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Dubey V.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College
Chinese Chemical Letters | Year: 2011

In this paper the effect of temperature on the mechanoluminescence of Au doped phosphors of (Zn,Cd)S is described. It is found that the ML disappears beyond a particular temperature. The temperature dependence of ML intensity follows the relation I = IT 0(1 - T/TC) n, where IT 0 is a constant, n is the slop of log IT versus log (1 - T/TC) plot which lies between 0.9 and 1.10, TC is the temperature at which ML disappear. It is found that the ML intensity in (Zn,Cd)S:Au disappear at 600 K. © 2010 Jagjeet Kaur. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.


Katre Y.,Kalyan Post Graduate College | Goyal N.,Kalyan Post Graduate College | Kumar Singh A.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College
Zeitschrift fur Physikalische Chemie | Year: 2011

The effect of cationic surfactant cetyltrimethylammonium bromide (CTAB) on the oxidation of L-leucine by N-bromophthalimide (NBP) has been studied at 308 K. The reaction exhibits first order dependence on NBP and L-leucine and negative and fractional order dependence on HClO4. The effects of KCl, KBr, phthalimide and mercuric acetate have also been studied and summarized. The rate of reaction increased with an increase in dielectric constant of the medium. CTAB strongly catalyzes the reaction and typical k obs and CTAB profile was observed, i.e., with a progressive increase in CTAB, the reaction rate increased and after achieving a peak kobs decreased at higher concentrations of CTAB. The results are treated quantitatively in terms of "Piszkiewicz" and "Raghvan and Srinivasan's" models. The various activation parameters in presence and absence of CTAB have been also evaluated. A suitable mechanism consistent with the experimental findings has been proposed. The rate constant in micellar phase kM, cooperativity index (n), binding constant (K1 and K2) have been computed. © by Oldenbourg Wissenschaftsverlag, München.


Parganiha Y.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Kaur J.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Dubey V.,Bhilai Institute of Technology | Chandrakar D.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College
Superlattices and Microstructures | Year: 2014

The present paper reports thermoluminescence (TL) glow curves and photoluminescence (PL) studies of europium doped yttrium silicate (Y2SiO5:Eu3+). The samples were prepared by the modified Solid state method which is the most suited method for large scale production. Starting material used for sample preparation was Y2O3, SiO2 and Eu2O3 with variable concentration of europium. A prepared sample was characterized by XRD (X-ray diffraction) and crystallite size found 20-50 nm in size. The PL excitation spectra was found at 265 and 395 nm while the emission spectra was found at 580, 588, 595, 598, 612, 615, 623 and 626 nm, the emission peak at 612 nm was most intense peak for all Eu3+ concentration. The effect of Eu3+ concentration on PL intensity was studied and found that intensity increases with increasing concentration up to 2.5 mol% of Eu3+. Commission Internationale de l'Eclairage co-ordinate (CIE) of this phosphor is (0.65, 0.31) in the red region. TL glow curves were recorded for different doses of UV exposure at a heating rate of 6.7 °C s-1. The kinetic parameters as activation energy "E", the order of kinetics "b", and the frequency factor "s" of Y2SiO5:Eu3+ have been calculated by using peak shape method. The sample shows general order kinetics. The effect of Eu3+ concentration on TL intensity was also studied and found that the intensity increases linearly up to 1 mol% and then decreases with increasing concentration of Eu3+. The present phosphor acts as a single host for red emission display devices and light emitting diode (LED) as well as may be used for thermoluminescence dosimetric material under UV exposure. © 2014 Elsevier Ltd. All rights reserved.


Parganiha Y.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Kaur J.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Dubey V.,Bhilai Institute of Technology | Shrivastava R.,ICFAI University, Tripura
Superlattices and Microstructures | Year: 2015

Abstract Yttrium aluminum perovskite (YAP) is a promising high temperature ceramic material, known for its mechanical, structural and optical properties. YAP's also known as an ideal host material for solid-state lasers and phosphors. In this work, Ce3+ doped YAlO3 phosphors were synthesized by solid state reaction method, which is very suitable technique for large scale production. A prepared phosphor was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Photoluminescence spectra and Thermoluminescence (TL) glow curve study. The starting reagents used for sample preparation are Y2O3, Al2O3 and CeO2, boric acid used as a flux. Ratio of Y:Al was 1:1 which shows perovskite structure confirmed by the X-ray diffraction (XRD) study. The entire prepared sample was studied by PL excitation and emission spectra. Prominent peak at 446 nm (blue emission) which shows broad emission spectra of photoluminescence. It proves that prepared phosphor can act as a single host for blue emission of light and can be used for display applications. Commission Internationale de I'Eclairage (CIE) techniques proves the blue emission of light (x =.148, y =.117). TL glow curve analysis of prepared phosphor shows the prominent peak at 189 °C for the variable UV exposure time and high temperature peak shows the more stability and less fading in the prepared phosphor. Kinetic data of prepared phosphor were evaluated by peak shape method for variable UV exposure time (5-25 min). © 2015 Elsevier Ltd.


Parganiha Y.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Kaur J.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Dubey V.,Bhilai Institute of Technology | Murthy K.V.R.,M. S. University of Baroda
Materials Science in Semiconductor Processing | Year: 2015

Cerium doped yttrium oxy-orthosilicate (Y2SiO5:Ce3+) phosphor was synthesized by modified solid state reaction method, which is low cost and useful for large scale production. A sample was characterized by X-ray diffraction (XRD) technique as well as field emission gun scanning electron microscopy. The crystallite size was calculated by Scherer's formula. The effect of Ce3+ concentration on photoluminescence studies was interpreted. The sample shows good PL spectra in the violet and blue region. The excitation spectra monitored at 400 nm and emission spectra monitored at 360 nm. The spectrophotometric determination was calculated by Commission Internationale de I'Eclairage technique. Using this phosphor, the desired CIE values including emissions throughout the violet (360 nm) and blue (427 nm) of the spectra were achieved. Efficient blue light emitting diodes were fabricated using Ce3+ doped phosphor based on near ultraviolet (NUV) excited LED lights. © 2015 Published by Elsevier Ltd.


Dubey V.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Kaur J.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Suryanarayana N.S.,Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College | Murthy K.V.R.,M. S. University of Baroda
Research on Chemical Intermediates | Year: 2013

This paper reports the thermoluminescence (TL) and chemical characterization of natural calcite collected from Kodwa mines of the C.G. Basin. The sample was irradiated with a 10-Gy dose from an Sr-90 beta source. The heating rate used for TL measurements was 6.7 /s. The sample had a good TL peak at approximately 127 C and the corresponding kinetic parameter were calculated. The effect of annealing temperature is also described for natural calcite. The photoluminescence excitation spectrum at ~254 nm and the corresponding emission spectrum peak at 395 nm are reported. Inductively coupled plasma-activated emission spectroscopy (ICP-AES) was conducted to determine the percentages of elements in the calcite mineral. © 2012 Springer Science+Business Media Dordrecht.

Loading Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College collaborators
Loading Government Vishwanath Yadav Tamaskar Post Graduate Autonomous College collaborators