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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. Source


Tiwari A.,Government Lahiri College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University | Kher R.S.,Government E R R Science Pg College
Luminescence | Year: 2015

Mercaptoethanol (ME), mercaptopropionic acid (MPA) and L-cysteine (L-Cys) having -SH functional groups were used as surface passivating agents for the wet chemical synthesis of ZnS nanoparticles. The effect of the thiol group on the optical and photoluminescence (PL) properties of ZnS nanoparticles was studied. L-Cysteine-capped ZnS nanoparticles showed the highest PL intensity among the studied capping agents, with a PL emission peak at 455 nm. The PL intensity was found to be dependent on the concentration of Zn2+ and S2- precursors. The effect of buffer on the PL intensity of L-Cys-capped ZnS nanoparticles was also studied. UV/Vis spectra showed blue shifting of the absorption edge. © 2015 John Wiley & Sons, Ltd. Source


Tiwari A.,Government Lahiri College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
RSC Advances | Year: 2016

ZnS has been one of the most investigated II-IV semiconductor materials, known for very interesting optoelectronic properties and its versatile applications in various fields. The transition from bulk to nano regime has brought forth some drastic changes in the optical properties of ZnS. In this review article, we have comprehensively discussed the surface passivation of ZnS nanoparticles by various polymeric ligands/matrix. Systematic investigation has been reported for state of the art synthesis and novel strategies for fabrication of ZnS nanocomposites have been discussed. A brief account of the pioneer works for ZnS has been described and their fundamental properties have been discussed. The characterization techniques in understanding the formation and stabilization of ZnS nanocomposites are highlighted. The article primarily focuses on the main features, synthesis techniques, and optical properties of polymer based ZnS nanocomposites. We have tried to cover recent application and developments in field of polymer based ZnS nanocomposites in biosensing, cell tagging, optoelectronic devices, heterogeneous catalysis, photocatalytic application etc. Overall this article provides an insight to optimize the synthetic routes and condition for better utilization of ZnS nanocomposites and provide an outlook to expand these applications to other areas, such as drug delivery, labeling, tracking agents, bioanalytical sensors, fluorescent probes, optics, information storage, and optoelectronics. © 2016 The Royal Society of Chemistry. Source


Tiwari A.,Government Lahiri 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 | Chandel A.L.S.,Government E R R Pg Science College
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 325 nm, respectively. PL of nanocomposites shows broad peaks in the violet-blue region (420-450 nm). 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. Copyright © 2015 John Wiley & Sons, Ltd. Source


Kurrey M.S.,Government Engineering College | Tiwari A.,Government Lahiri College | Khokhar M.S.K.,Guru Ghasidas University | Kher R.S.,Government ERR PG Science College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University
Journal of Luminescence | Year: 2015

Nanocrystalline YAG doped with Eu3+ and Nd3+ has been synthesized by a sol-gel technique. The prepared nanophosphors were calcined and characterized by XRD, SEM. The XRD analysis revealed well-defined cubic phase. Electron microscopy showed spherical morphologies with an average size of 15-20 nm. The thermoluminescence (TL) properties of as prepared nanophosphors were investigated after γ-irradiation using 60Co source at room temperature. It has been found that there is a prominent TL glow peak at 290-295 °C for the as prepared doped samples. The TL glow curve showed variation in TL peak intensity as the concentration of dopant is changed. Kinetic data and trap depth for the synthesized samples were calculated by a peak shape method. It has been found that TL response is nonlinear in the range 0.29-1.16 kGy. This paper discusses about the optimal doping concentration of Eu and Nd in YAG nanophosphors. © 2015 Elsevier B.V. All rights reserved. Source

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