Bilāspur, India
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Bajpai N.,Government E R R Pg Science College | Khan S.A.,Government College Seepat | Kher R.S.,Government E R R Pg Science College | Bramhe N.,Pandit Ravishankar Shukla University | And 2 more authors.
Journal of Luminescence | Year: 2014

Nanocrystalline tin oxide (IV) doped with Eu3+ has been synthesized by sol-gel technique. The prepared SnO2:Eu3+ nanoparticles were calcined and characterized by XRD, SEM, TEM and FTIR. The XRD analysis revealed well crystallised tetragonal rutile phase. Electron microscopy showed spherical morphologies with an average size of 15-20 nm. The thermoluminescence (TL) properties of SnO2:Eu3+ nanoparticles were investigated after γ-irradiation using 60Co source at room temperature. The TL glow curve showed variation in TL peak intensity as the concentration of dopant is changed. It has been found that TL response of linear in the range 0.5-2.0 kGy. This paper discusses about the optimal doping concentration of Europium in SnO2 nanoparticles and its dosimetric application has also been studied. © 2013 Elsevier B.V.


Tiwari A.,Government e R R PG Science College | Khan S.A.,Government College Seepat | Kher R.S.,Government e R R PG Science College | Mehta M.,Government e R R PG Science College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Journal of Luminescence | Year: 2011

Mechanoluminescence (ML) properties of γ-irradiated and non-irradiated capped ZnS:Cu nanophosphors have been investigated. The nanoparticles were prepared by wet chemical method using different capping agents. The samples were characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). ML was excited impulsively by dropping a load on to the sample. Two peaks have been observed in the ML intensity versus time curve. It has been found that ML intensity rises with time, attains a maximum and then decays. The ML intensity of γ-irradiated SiO2 capped ZnS:Cu nanophosphors was found to be the highest amongst the presently investigated nanophosphors. Mechanism of ML has been explained on the basis of piezoelectrically induced charge carrier detrapping model. © 2011 Elsevier B.V. All rights reserved.


Tiwari A.,Government e R R PG Science College | Khan S.A.,Government College Seepat | Kher R.S.,Government e R R PG Science College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University | Mehta M.,Government e R R PG Science College
Journal of Luminescence | Year: 2011

ZnS:Cu nanophosphors were prepared by wet chemical methods and characterized by X-ray diffraction (XRD). The typical morphologies of the nanophosphors were investigated by scanning electron microscopy (SEM). The thermoluminescence (TL) properties of inorganically and organically passivated ZnS:Cu nanophosphors were investigated after γ-irradiation using a 60Co source at room temperature. The TL glow curve of capped ZnS:Cu showed variation in TL peak and intensity as the capping agent was changed. Amongst the synthesized samples the TL glow curve of SiO2 capped ZnS:Cu showed the highest TL intensity. It has been found that TL response of SiO2 capped ZnS:Cu is linear in the range 10550 Gy. A discussion of the obtained results is also presented. © 2011 Elsevier B.V.


Tiwari A.,Government E R R Pg Science College | Khan S.A.,Government College Seepat | Kher R.S.,Government E R R Pg Science College
Current Applied Physics | Year: 2012

The synthesis of Cu doped ZnS nanoparticles inside the pore of an inorganic silica gel matrix is presented. The synthesized nanoparticles were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). X-ray diffraction pattern reveals the crystalline wurtzite phase of ZnS. The existence of silica gel in modeling morphologies of the nanoparticles was characterized using Fourier transform infrared (FTIR) spectrometer. Thickness of the silica shell was also calculated. UV- absorption spectrum shows the appearance of an absorption peak at 273 nm which confirms the blue shift as compared to that of bulk ZnS. The photoluminescence (PL) emission spectrum of the sample showed a broad band in the range 465-510 nm due to the transition from the conduction band edge of ZnS nanocrystals to the acceptor like t 2 state of Cu. © 2011 Elsevier B.V. All rights reserved.


Tiwari A.,Guru Ghasidas University | Khan S.A.,Government College Seepat | Kher R.S.,Government Err Pg Science College
Journal of Luminescence | Year: 2012

Copper doped ZnS nanoparticles stabilized by sodium hexametaphosphate (SHMP) have been prepared via the wet chemical method using thiourea and sodium sulphide as chalcogenide sources. The XRD pattern showed that ZnS nanoparticles had zinc blende structure and line broadening suggests the formation of an amorphous compound. Absorption measurements were done for three different concentrations of dopant concentrations. The PL spectrum for the sample synthesized using Na 2S·9H 2O showed a sharp emission peak around 510 nm with full width at half maximum (FWHM)<10 nm. The role of the capping agent and sulphide source on optical properties of as synthesized nanoparticles by steady-state photoluminescence (PL) spectroscopy has been studied. © 2012 Elsevier B.V.


PubMed | Government E R R Pg Science College, Government Lahiri College, Government College Seepat and Rashtrasant Tukadoji Maharaj Nagpur University
Type: Journal Article | Journal: Luminescence : the journal of biological and chemical luminescence | Year: 2016

Nanostructured polymer-semiconductor hybrid materials such as ZnS-poly(vinyl alcohol) (ZnS-PVA), ZnS-starch and ZnS-hydroxypropylmethyl cellulose (Zns-HPMC) are synthesized by a facile aqueous route. The obtained nanocomposites are characterized using various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV/vis spectroscopy and photoluminescence (PL). XRD studies confirm the zinc blende phase of the nanocomposites and indicate the high purity of the samples. SEM studies indicate small nanoparticles clinging to the surface of a bigger particle. The Energy Dispersive Analysis by X-rays (EDAX) spectrum reveals that the elemental composition of the nanocomposites consists primarily of Zn:S. FTIR studies indicate that the polymer matrix is closely associated with ZnS nanoparticles. The large number of hydroxyl groups in the polymer matrix facilitates the complexation of metal ions. The absorption spectra of the specimens show a blue shift in the absorption edge. The spectrum reveals an absorption edge at 320, 310 and 325nm, respectively. PL of nanocomposites shows broad peaks in the violet-blue region (420-450nm). The emission intensity changes with the nature of capping agent. The PL intensity of ZnS-HPMC nanocomposites is found to be highest among the studied nanocomposites. The results clearly indicate that hydroxyl-functionalized HPMC is much more effective at nucleating and stabilizing colloidal ZnS nanoparticles in aqueous suspensions compared with PVA and starch.


Tiwari A.,P.A. College | Khan S.A.,Government College Seepat | Kher R.S.,P.A. College
Bulletin of Materials Science | Year: 2011

3-Thiopropionic acid (TPA) capped ZnS:Cu nanocrystals have been successfully synthesized by simple aqueous method. Powder X-ray diffraction (XRD) studies revealed the particle size to be 4·2 nm. Surface characterization of the nanocrystals by FTIR spectroscopy has been done and the structure for surface bound TPA based on spectral analysis was proposed. The optical studies were done using UV-VIS spectroscopy and particle size and diameter polydispersity index (DPI) were calculated. Photoluminescence (PL) spectrum reveals emission related to the transition from conduction band of ZnS to t2 level of Cu2+. Electron microscopy was also done by scanning electron microscopy (SEM). © Indian Academy of Sciences.


Tiwari A.,P.A. College | Khan S.A.,Government College Seepat | Kher R.S.,P.A. College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Journal of Applied Spectroscopy | Year: 2011

ZnS:Cu nanocrystals capped with different capping molecules have been successfully synthesized by a simple aqueous method. The prepared nanocrystals were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive analysis by X-rays (EDAX). The surface characterization of the nanocrystals was done by FTIR spectroscopy. The effect of capping agents on absorption and photoluminescence (PL) spectra of the ZnS:Cu nanocrystals was studied. A blue shift of the absorption peaks was observed and attributed to a quantum confinement effect, which increases the band gap energy. The photoluminescence spectra of the capped ZnS:Cu nanocrystals showed a broad peak in the range of 460-480 nm. The intensity of the PL spectra strongly depended on the capping agents. © 2011 Springer Science+Business Media, Inc.


Chandel A.L.S.,P.A. College | Khan S.A.,Government College Seepat | Kher R.S.,P.A. College | Tiwari A.,P.A. College
Luminescence | Year: 2012

We studied the chemiluminescence (CL) oxidation of phenyl hydrazine-luminol with various organic and inorganic peroxides. Maximum CL intensity for this system was obtained for t-butylhydroperoxide. The enhancement in CL depended strongly on pH and was greatest at pH 12.5. The solvent drastically enhanced the CL intensity. DMSO was found to increase the CL intensity many-fold as compared to acetonitrile and water. The effect of temperature on CL intensity has also been studied. The CL spectra revealed a broad peak at 425 nm, which suggests excited 3-aminophthalate ion as the luminophor. A mechanism to explain the reactions is suggested. Copyright © 2012 John Wiley & Sons, Ltd.


Rai R.K.,Government Engineering College | Kher R.S.,P.A. College | Khan S.A.,Government College Seepat | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University | Upadhyay A.K.,O P Jindal Institute of Technology
Indian Journal of Pure and Applied Physics | Year: 2012

A low cost set-up has been designed and developed for producing mechanoluminescence (ML) by continuously varying pressure on the sample. The ML of γ-irradiated BaAl 2O 4:Eu phosphor has been studied. ML is excited impulsively by dropping a load through guiding cylinder and by applying continuously varying pressure on the sample. When BaAl 2O 4:Eu phosphor is deformed impulsively, a single peak with shoulder is observed in the time versus ML intensity curve, while number of peak is observed when continuously increasing pressure applied on to the sample. When pressure is continuously decreased less number of peaks is observed as compared to that of increasing pressure. The enhancement in ML intensity with γ-irradiation suggests that BaAl 2O 4:Eu is a suitable candidate for ML dosimetry.

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