Government Arts and Commerce Girls College

Devendranagar, India

Government Arts and Commerce Girls College

Devendranagar, India
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Sharma R.,Government Arts and Commerce Girls College | BiSen D.P.,Pandit Ravishankar Shukla University | Chandra B.P.,Rani Durgavati University
Journal of Electronic Materials | Year: 2015

We report the synthesis and mechanoluminescence (ML) of manganese-doped zinc sulfide (ZnS) nanoparticles. Clusters of ZnS:Mn nanocrystals were prepared by chemical precipitation, by mixing of solutions of zinc chloride, sodium sulfide, and manganese chloride. Mercaptoethanol (ME) was used as capping agent, to modify the surface of the nanoparticles and prevent their growth. The particle size of the nanocrystals, measured by use of x-ray diffraction and transmission electron microscopy, was in the range 2–5 nm. The ZnS:Mn nanoparticles were deformed impulsively by dropping a load from a fixed height. The ML intensity of ZnS:Mn nanocrystals increased with increasing mechanical stress i.e. with increasing impact velocity. The impact velocity-dependence of maximum ML intensity, Im, and total ML intensity, IT, are discussed. The effect of crystal size on the ML intensity–time curve is also discussed. ML intensity initially increases with increasing concentration of Mn in the samples, reaches an optimum value at a specific concentration of Mn, then decreases with further increasing concentration of Mn in the nanocrystals. The theory of the ML of nanoparticles is also discussed. © 2015, The Minerals, Metals & Materials Society.


Sharma R.,Government Arts and Commerce Girls College | Bisen D.P.,Pandit Ravishankar Shukla University | Chandra B.P.,Rani Durgavati University
Journal of Luminescence | Year: 2015

Nanosized strontium aluminate phosphors activated with Dy3+ were prepared by a combustion method. Nanophosphor was prepared by this method at reaction temperatures as low as 600 °C. Powder X-ray diffraction (XRD), scanning electron microscope analysis was used to characterize the prepared product. The monoclinic phase was observed in the XRD pattern. The particle size of the samples was calculated around 35 nm. The SEM images show irregular shape of the prepared nanophosphor. Two peaks were found in the mechanoluminescence (ML) response curve plotted between time and ML intensity. The H3BO3 added strontium aluminate phosphors activated with Dy show more bright ML peak as compared to the powders of SrAl2O4:Dy3+ without H3BO3. It was found that the PL and ML intensity increases with increasing concentration of Dy, it becomes maximum for 3% of Dy. The photoluminescence emission shows two intense fluorescence transitions peaks at 498 nm and 583 nm, 4F9/2→6H15/2 in the blue and 4F9/2→6H13/2 in the yellow-orange wavelength region. © 2015 Elsevier B.V. All rights reserved.


Bisen D.P.,Pandit Ravishankar Shukla University | Sharma R.,Government Arts and Commerce Girls College
Luminescence | Year: 2016

In this paper, europium-doped strontium aluminate (SrAl2O4:Eu2+) phosphors were synthesized using a combustion method with urea as a fuel at 600°C. The phase structure, particle size, surface morphology and elemental analysis were studied using X-ray diffractometry (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX) and Fourier transform infrared (FTIR) spectra. The EDX and FTIR spectra confirm the elements present in the SrAl2O4:Eu2+ phosphor. The optical properties of SrAl2O4:Eu2+ phosphors were investigated by photoluminescence (PL) and mechanoluminescence (ML). The excitation and emission spectra showed a broad band with peaks at 337 and 515 nm, respectively. The ML intensities of SrAl2O4:Eu2+ phosphor increased proportionally with the increase in the height of the mechanical load, which suggests that this phosphor could be used in stress sensors. The CIE colour chromaticity diagram and ML spectra confirm that the SrAl2O4:Eu2+ phosphor emitted green coloured light. Copyright © 2015 John Wiley & Sons, Ltd.


Sahu N.,Pandit Ravishankar Shukla University | Brahme N.,Pandit Ravishankar Shukla University | Sharma R.,Government Arts and Commerce Girls College
Luminescence | Year: 2016

CdSe nanoparticles were synthesized by green route and chemical route methods. In the green route method the samples were capped by starch and in the chemical route method the samples were capped by mercaptoacetic acid (MAA). The samples were characterized by powder X- ray diffraction (XRD) and transmission electron microscopy (TEM). Both the samples showed zinc blend structure. The optical absorption spectra and Fourier transform infrared (FTIR) spectra were also studied. A blue shift was seen in the absorption spectra as compared with the bulk as well as the sample capped by starch. TEM images showed agglomeration for the starch-capped sample as compared with the MAA-capped sample. The particle size for the sample capped by MAA was found to be less as compared with the starch-capped sample. A blue shift in the photoluminescence (PL) spectra was also recorded for the samples prepared by the chemical route as compared with the sample prepared by the green route as well as the bulk. The PL peak shifted towards the red side and increase in the peak intensity occurred with the change in the excitation wavelength. Change in PL intensity was observed with different pH at 685 nm. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.


Sharma R.,Government Arts and Commerce Girls College | Bisen D.P.,Pandit Ravishankar Shukla University
Luminescence | Year: 2014

The thermoluminescence (TL) of nanoparticles has become a matter of keen interest in recent times but is rarely reported. This article reports the synthesis of ZnS:Mn nanocrystals using a chemical route, with mercaptoethanol (ME) as the capping agent. The particle sizes for the nanocrystals were measured by X-ray diffraction (XRD) and also by studying transmission electron microscopy (TEM) patterns. The particle sizes of the synthesized samples were found to be between 1 and 3 nm. For samples with different concentrations of the capping agent, it was found that the TL intensity of the ZnS:Mn nanoparticles increased as the particle size decreased. A shift in the peak position of the TL glow curve was also seen with decreasing particle size. The TL intensity was found to be maximal for samples with 1.2% of Mn. A change in the peak position was not found for samples with different concentrations of Mn. The half-width glow peak curve method was used to determine the trap-depth. The frequency factor of the synthesized samples was also calculated. The stability of the charge carriers in the traps increases with decreasing nanoparticle size. The higher stability may be attributed to the higher surface/volume ratio and also to the increase in the trap-depth with decreasing particle size. Copyright © 2014 John Wiley & Sons, Ltd.


Sahu I.P.,Pandit Ravishankar Shukla University | Bisen D.P.,Pandit Ravishankar Shukla University | Sharma R.,Government Arts and Commerce Girls College
Research on Chemical Intermediates | Year: 2015

Eu, Dy co-doped strontium aluminate nanophosphors were prepared by the combustion synthesis method. Their structure and morphology were investigated by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy. According to the XRD and the TEM analysis, the average crystallite size was found to be in the nanometer range. The phase structure of the prepared nanophosphor is consistent with a standard monoclinic phase with a space group P21. The prepared SrAl2O4:Eu2+, Dy3+ nanophosphor emitted green light with a peak at 510 nm showing blue shift, which is due to the reduction in the particle size. Two distinct peaks were observed in the ML intensity versus time curve. The two peaks in ML indicate the presence of charge transfer in an ML process. © 2015 Springer Science+Business Media Dordrecht


PubMed | Government Arts and Commerce Girls College and Pandit Ravishankar Shukla University
Type: Journal Article | Journal: Luminescence : the journal of biological and chemical luminescence | Year: 2016

In this paper, europium-doped strontium aluminate (SrAl2O4:Eu(2+)) phosphors were synthesized using a combustion method with urea as a fuel at 600C. The phase structure, particle size, surface morphology and elemental analysis were studied using X-ray diffractometry (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX) and Fourier transform infrared (FTIR) spectra. The EDX and FTIR spectra confirm the elements present in the SrAl2O4:Eu(2+) phosphor. The optical properties of SrAl2O4:Eu(2+) phosphors were investigated by photoluminescence (PL) and mechanoluminescence (ML). The excitation and emission spectra showed a broad band with peaks at 337 and 515 nm, respectively. The ML intensities of SrAl2O4:Eu(2+) phosphor increased proportionally with the increase in the height of the mechanical load, which suggests that this phosphor could be used in stress sensors. The CIE colour chromaticity diagram and ML spectra confirm that the SrAl2O4:Eu(2+) phosphor emitted green coloured light.


Ca

PubMed | Government Arts and Commerce Girls College and Pandit Ravishankar Shukla University
Type: Journal Article | Journal: Luminescence : the journal of biological and chemical luminescence | Year: 2016

A series of Ce


PubMed | Government Arts and Commerce Girls College and Pandit Ravishankar Shukla University
Type: Journal Article | Journal: Luminescence : the journal of biological and chemical luminescence | Year: 2016

CdSe nanoparticles were synthesized by green route and chemical route methods. In the green route method the samples were capped by starch and in the chemical route method the samples were capped by mercaptoacetic acid (MAA). The samples were characterized by powder X- ray diffraction (XRD) and transmission electron microscopy (TEM). Both the samples showed zinc blend structure. The optical absorption spectra and Fourier transform infrared (FTIR) spectra were also studied. A blue shift was seen in the absorption spectra as compared with the bulk as well as the sample capped by starch. TEM images showed agglomeration for the starch-capped sample as compared with the MAA-capped sample. The particle size for the sample capped by MAA was found to be less as compared with the starch-capped sample. A blue shift in the photoluminescence (PL) spectra was also recorded for the samples prepared by the chemical route as compared with the sample prepared by the green route as well as the bulk. The PL peak shifted towards the red side and increase in the peak intensity occurred with the change in the excitation wavelength. Change in PL intensity was observed with different pH at 685nm. Copyright 2016 John Wiley & Sons, Ltd.


Sharma R.,Government Arts and Commerce Girls College | Sharma U.,Government Arts and Commerce Girls College
Journal of Alloys and Compounds | Year: 2015

Eu2+ doped strontium aluminate nanophosphors are prepared by combustion method. The X-ray diffraction (XRD) and transmission electron microscope (TEM) studies showed the emergence of mixed phase for higher concentration of H3BO3. The effect of fluxing agent H3BO3 on the phase structure and on the luminescence properties; such as mechanoluminescence (ML) and photoluminescence (PL) properties of SrAl2O4:Eu2+ nanophosphors are investigated. The variation in fluxing agent H3BO3 influenced the PL and ML intensity and the maximum PL and ML intensity was observed for 7.5% H3BO3. The PL emission and ML spectra showed broad band at 515 nm corresponding to the 4f65d1 → 4f7 transition. The PL and ML for different amount of Eu revealed that the optimal concentration of Eu is 3%. An initial rapid decay followed by long-lasting phosphorescence was observed for the synthesized samples. © 2015 Elsevier B.V. All rights reserved.

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