Niyaz Parvin Shaik; N. V. Poornachandra Rao; K. V. R. Murthy
Abstract
Pure LaPO4 and LaPO4: Eu (0.5 mol %) Ce (0.5 mol %) phosphors were synthesized by the solid-state reaction method. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) spectra and the particle size analysis were used to characterize ...
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Pure LaPO4 and LaPO4: Eu (0.5 mol %) Ce (0.5 mol %) phosphors were synthesized by the solid-state reaction method. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) spectra and the particle size analysis were used to characterize these samples. The XRD results reveal that the synthesized LaPO4:Eu (0.5 mol%) Ce (0.5 mol%) phosphors are well crystalline and assigned to the monoclinic structure with a main (120) diffraction peak. The calculated crystallite size of pure LaPO4 and LaPO4:Eu, Ce phosphors were 67.6nm and 64nm respectively. Upon excitation at 254nm wavelength, the emission spectrum of pure LaPO4 phosphor emits a maximum intensity peak at 470 (blue) nm. In the emission spectrum of LaPO4:Eu 3+ Ce 3+ phosphor, the low contributions of the red (613nm) 5D0-7F2 emissions and the high intensity of the orange-red (589nm)5D0-7F1 emission results in high color purities.The most intense emissions appearing in the 580-620nm region is responsible for the strong orange-red luminescence observed in the Eu,Ce doped LaPO4 phosphor whose CIE colour coordinates are x = 0.57 and y = 0.43.Thus the prepared phosphors can be used as an orange-red emitting material in the field of illuminations and display devices.
Nikita H. Patel; M.P. Deshpande; Sandip V. Bhatt; Kamakshi R. Patel; S. H. Chaki
Abstract
Undoped and Mn doped CdS nanoparticles with varying Mn concentration of 10,15 and 20 mol % have been prepared by chemical co-precipitation method with polyvinylpyrrolidone (PVP) as capping agent at room temperature. EDAX has shown that no foreign impurities are present in the synthesized nanoparticles ...
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Undoped and Mn doped CdS nanoparticles with varying Mn concentration of 10,15 and 20 mol % have been prepared by chemical co-precipitation method with polyvinylpyrrolidone (PVP) as capping agent at room temperature. EDAX has shown that no foreign impurities are present in the synthesized nanoparticles and X-ray diffraction (XRD) revealed that undoped and Mn doped CdS nanoparticles possess cubic phase with crystallite size ranging from 4-6 nm. Transmission electron microscopy (TEM) images indicated that nanoparticle sizes are between 2-6 nm and exhibits polycrystalline nature as seen from selected area electron diffraction (SAED) pattern. Raman spectra of undoped and Mn-doped CdS nanoparticles have shown 1LO and 2LO phonon modes and their intensity ratio decreases as Mn concentration increases. Magnetic susceptibility clearly pointed out that undoped CdS behaves as diamagnetic whereas Mn doped CdS as paramagnetic and varies nonlinearly with Mn concentration in CdS. Rapid increase in magnetization below 50 K temperature is observed in M-T curves which can be assigned to Mn ions isolated in CdS crystal field or extrinsic defects. The M-H curve at 5 K and 300 K for 20% Mn doped CdS nanoparticles at different magnetic fields showed no hystersis. In near future Mn doped CdS nanoparticles can be used for application in dilute magnetic semiconductor and fabrication of solar cells. The result and discussion drawn from this work are elaborated in detail in the paper.
Vishal R. Panse; N.S. Kokode; S.J. Dhoble
Abstract
In this paper we present luminescence results on Tb 3+ doped Sr2(BO3)Cl green phosphor. The vibrational properties of Sr2(BO3)Cl phosphor was studied by Fourier transform infrared spectroscopy. Photoluminescence studies have been carried out to understand the mechanism of excitation and the corresponding ...
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In this paper we present luminescence results on Tb 3+ doped Sr2(BO3)Cl green phosphor. The vibrational properties of Sr2(BO3)Cl phosphor was studied by Fourier transform infrared spectroscopy. Photoluminescence studies have been carried out to understand the mechanism of excitation and the corresponding emission in the as prepared phosphor. As the Tb 3+ ion is commonly used as an activator for the green emission, the excitation and emission spectra indicate that this phosphor can be effectively excited by 380 nm, to exhibit bright green emission centered at 546 nm corresponding to the f→f transition of Tb3 +ions.
T. Diana; D. C. Agarwal; P. K. Kulriya; S. K. Tripathi; H. Nandakumar Sarma
Abstract
100 MeV Ag ions have been used to study the swift heavy ion (SHI) induced modification in Te/Bi bilayer system. The samples were analysed using Rutherford backscattering spectroscopy (RBS), Atomic force microscopy (AFM) and X-ray diffractometer (XRD). The elemental depth study with RBS results show a ...
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100 MeV Ag ions have been used to study the swift heavy ion (SHI) induced modification in Te/Bi bilayer system. The samples were analysed using Rutherford backscattering spectroscopy (RBS), Atomic force microscopy (AFM) and X-ray diffractometer (XRD). The elemental depth study with RBS results show a strong mixing between the top Te layer and the underlying Bi layer on irradiation. Surface roughness as calculated by AFM is found to increase from 8 to 30 nm on irradiation for the fluence 3x10 13 ions/cm 2 . XRD results confirm the formation of Bi-Te alloy phases on mixing and are expected to be formed due to the interfacial reaction taking place within the molten ion tracks. Ion beam mixing has the potential to induce the formation Bi-Te alloy thin films which are the promising candidate for thermoelectric applications near room temperature.
Anita Mekap; Piyush R. Das; R. N. P. Choudhary
Abstract
The polycrystalline sample of ZnSb2O4 was prepared by a high-temperature solid-state reaction technique. Preliminary X-ray diffraction (XRD) studies of powder sample of ZnSb2O4 showed the formation of single-phase compound at room temperature. The surface morphology of the pellet sample of ZnSb2O4 was ...
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The polycrystalline sample of ZnSb2O4 was prepared by a high-temperature solid-state reaction technique. Preliminary X-ray diffraction (XRD) studies of powder sample of ZnSb2O4 showed the formation of single-phase compound at room temperature. The surface morphology of the pellet sample of ZnSb2O4 was recorded at room temperature using a scanning electron microscope (SEM). Detailed studies of dielectric properties (εr, tan δ) and impedance parameters of the material provide an insight into the electrical properties and understanding of types of relaxation process occurred in the material. Temperature variation of dc conductivity shows that this compound exhibits negative temperature coefficient of resistance (NTCR) and frequency dependence of ac conductivity suggests that the material obeys Jonscher’s universal power law.
A. Kumar;Somik Banerjee
Abstract
Structural and conformational modifications in conducting polymer nanostructures viz., Polyaniline (PAni) nanofibers induced by swift heavy ion (SHI) irradiation have been investigated employing TEM, XRD, UV-Vis, FTIR and micro-Raman spectroscopy. Upon interaction with the highly energetic ions, PAni ...
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Structural and conformational modifications in conducting polymer nanostructures viz., Polyaniline (PAni) nanofibers induced by swift heavy ion (SHI) irradiation have been investigated employing TEM, XRD, UV-Vis, FTIR and micro-Raman spectroscopy. Upon interaction with the highly energetic ions, PAni nanofibers are fragmented and get amorphized. The local range of order is found to decrease with a corresponding increase in the concentration of point defects and dislocations leading to the enhancement in strain. Vibrational spectra of the pristine and SHI irradiated PAni nanofibers studied using FTIR and micro-Raman (μR) spectroscopy indicate conformational changes in PAni nanofibers upon SHI irradiation. Loss of π-stacking due to the enhancement in the torsion angle between Cring-N-Cring upon irradiation is indicative of strong electrostatic interaction between the electron rich C-N site in the aromatic rings of PAni chains and the ion beam. The most significant variation in PAni nanofibers upon SHI irradiation is the transformation of para di-substituted benzene (benzenoid) structure of PAni into the quinone di-imine (quinoid) structures; a phenomenon that has been simultaneously observed in both the FTIR and Raman spectra. The presence of two main peaks representing the same structures in PAni nanofibers in both the Raman and IR spectra is because of the presence of delocalized sp2 phases and local disorder in PAni nanofibers, which gives rise to electrical and mechanical fluctuations that destroy the symmetry rules.
Surender Kumar; Tukaram J. Shinde; Pramod N. Vasambekar
Abstract
Powder diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy were used to characterize the spinel structure of nanocrystalline Ferrites with composition Mn1-xZnxFe2O4 (x = 0.2, 0.4, 0.6 and 0.8) prepared by oxalate coprecipitation technique and followed by microwave heating ...
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Powder diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy were used to characterize the spinel structure of nanocrystalline Ferrites with composition Mn1-xZnxFe2O4 (x = 0.2, 0.4, 0.6 and 0.8) prepared by oxalate coprecipitation technique and followed by microwave heating of precursors. Effect of composition on the lattice constant, x-ray density, crystallite size was studied. Crystallite size and x-ray density increases with increase in Zinc content. The face centered cubic spinel structure has undergone deviation from ideality. A correlation exists between splitting of infrared absorption bands and lowering of composition dependent crystalline symmetry. This preparation technique could be used for synthesis of materials which use microwave transparent precursors.
R. Amutha
Abstract
Ultrathin (250 Å) initial deposit of copper on glass substrates were used for the subsequent deposition of ZnTe films under a pressure of 10 -5 m.bar by thermal evaporation method. The decrease of atomic percentage of copper with increase of the ZnTe film thickness is confirmed by EDAX analysis. ...
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Ultrathin (250 Å) initial deposit of copper on glass substrates were used for the subsequent deposition of ZnTe films under a pressure of 10 -5 m.bar by thermal evaporation method. The decrease of atomic percentage of copper with increase of the ZnTe film thickness is confirmed by EDAX analysis. The phase change from hexagonal to cubic structure is observed by XRD analysis. The strain (), grain size (D) and dislocation density ( ) were calculated and results are discussed. The transmittance and the optical bandgap energy were found decreases when increases of ZnTe film thickness. The optical transition of these films is found to be direct allowed.
Megha P. Mahabole; Ravindra U. Mene;Rajendra S. Khairnar
Abstract
This present paper deals with the investigation on effective utilization of cobalt doped hydroxyapatite (Co-HAp) thick films for improvement in gas sensing and dielectric properties. Chemical precipitation route is used for synthesis of nanocrystalline hydroxyapatite (HAp) bioceramic and ion exchange ...
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This present paper deals with the investigation on effective utilization of cobalt doped hydroxyapatite (Co-HAp) thick films for improvement in gas sensing and dielectric properties. Chemical precipitation route is used for synthesis of nanocrystalline hydroxyapatite (HAp) bioceramic and ion exchange process is carried out for the partial substitution of cobalt ions in HAp matrix. Hydroxyapatite thick films, prepared using screen printing technique, are used as samples for gas sensing and dielectric measurements. The structural identification of HAp thick films is carried out using X-ray diffraction and the presence of functional groups in pure and doped HAp is confirmed by means FTIR spectroscopy. The surface morphology of these films is visualized by means of SEM and AFM analysis. Detailed study on CO2 gas sensing performance of pure and Co-HAp thick films is carried out wherein operating temperature, response/recovery times and gas uptake capacity are determined. It is remarkable to note that Co-HAp film with 0.01M cobalt concentration shows maximum sensitivity to CO2 gas at relatively lower operating temperature of 135 o C in comparison with pure HAp as well as other concentrations of cobalt doped HAp films. The frequency dependent variation of dielectric constant (K) and dielectric loss (tan δ) of HAp thick films are also studied in the range of 10 Hz-1MHz at room temperature. The result shows that increase of cobalt concentration in HAp matrix leads to increase in dielectric constant. The study reveals clear influence of cobalt substitution on dielectric properties and gas sensing properties HAp matrix.
Dinesh C. Sharma; Y. K. Vijay;Y. K. Sharma; Subodh Srivastava
Abstract
The chromium doped zinc telluride (ZnTe:Cr) as well as ZnTe thin films and their sandwich structures were prepared onto glass substrate by thermal evaporation method under the vacuum of 10-5 Torr. We have studied the structural, optical and electrical properties of thermally evaporated Cr-doped ZnTe ...
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The chromium doped zinc telluride (ZnTe:Cr) as well as ZnTe thin films and their sandwich structures were prepared onto glass substrate by thermal evaporation method under the vacuum of 10-5 Torr. We have studied the structural, optical and electrical properties of thermally evaporated Cr-doped ZnTe thin films as a function of Cr concentration. XRD measurements show that Cr-doped ZnTe films possess the mix phase of cubical and hexagonal structure of ZnTe thin film. The optical energy band gap (Eg) calculated from the optical absorption spectra which was observed around 2.57 eV for undoped ZnTe, and reduced to 1.47 eV for the Cr-doped thin films. The result of I-V characteristics is also presented in this paper.
Saruchi Surbhi; Praveen Aghamkar; Sushil Kumar
Abstract
Nanomaterials and nanostructures have received steadily growing interests as a result of their peculiar and fascinating properties and applications. Neodymia-silica nanocomposites were prepared by sol-gel route followed by calcination. The samples were prepared with different concentration of dopant ...
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Nanomaterials and nanostructures have received steadily growing interests as a result of their peculiar and fascinating properties and applications. Neodymia-silica nanocomposites were prepared by sol-gel route followed by calcination. The samples were prepared with different concentration of dopant (Nd2O3) and calcined in a programmable furnace at 1000 °C for 5 h. The structural evolution of samples was investigated by employing techniques such as XRD, FTIR and TEM. X-ray diffraction patterns showed that the samples were nanocrystalline and the size of crystallites has been determined using Debye-Scherrer relation. The FTIR spectra confirmed the presence of functional groups of prepared material. The particle size of samples was also estimated through TEM analysis. It has been observed that crystallinity as well as particle size of the samples increases with increase in dopant concentration.
Naheed Ahmad; Seema Sharma;Radheshyam Rai
Abstract
We present a simple and eco-friendly biosynthesis of silver nanoparticles using Pomegranate peel extract as the reducing agent. Peel extract of Pomegranate was challenged with silver nitrate (AgNO3) and chloroauric acid (HAuCl4) solution for the production of silver nanoparticles (AgNPs) and gold nanoparticles ...
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We present a simple and eco-friendly biosynthesis of silver nanoparticles using Pomegranate peel extract as the reducing agent. Peel extract of Pomegranate was challenged with silver nitrate (AgNO3) and chloroauric acid (HAuCl4) solution for the production of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs), respectively. The reaction process was simple for the formation of highly stable silver and gold nanoparticles at room temperature by using the biowaste of the fruit. The morphology and crystalline phase of the NPs were determined from UV-Vis spectroscopy, transmission electron microscopy (TEM), selected area electron diffraction (SAED) and X-ray diffraction (XRD) spectra. TEM studies showed that the average particle size of silver nanoparticles were 5 ±1.5 nm whereas the gold nanoparticles were found to be 10 ±1.5 nm. An effort has been also been made to understand the possible involved mechanism for the biosynthesis of the NPs. Presumably biosynthetic products or reduced cofactors play an important role in the reduction of respective salts to nanoparticles.
B. B. Mohanty; M. P. K. Sahoo;R. N. P. Choudhary; P. S. Sahoo
Abstract
The polycrystalline Ba3Sr2GdTi3V7O30 material of tungsten bronze structural family was prepared by a high-temperature solid-state reaction technique. Preliminary X-ray diffraction analysis exhibits the formation of single-phase compound with orthorhombic crystal system. Surface micrograph recorded by ...
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The polycrystalline Ba3Sr2GdTi3V7O30 material of tungsten bronze structural family was prepared by a high-temperature solid-state reaction technique. Preliminary X-ray diffraction analysis exhibits the formation of single-phase compound with orthorhombic crystal system. Surface micrograph recorded by scanning electron microscopic (SEM) technique has well defined but non-uniformly distributed grains throughout the surface of the pellet sample. Detailed studies of dielectric properties as a function of temperature (306-773 K) and frequencies (10 2 -10 6 Hz) suggest that the compound has frequency independent diffused dielectric anomaly at a temperature ~620 K which may be related to ferroelectric phase transition which is confirmed from polarization study. The frequency and temperature dependence of impedance property of the material were analyzed using a complex impedance spectroscopy. The Nyquist plots confirmed the presence of grain and grain boundary effect in the material.
A. P. Mishra; A. Tiwari; Rajendra K. Jain
Abstract
The coordination complexes of Co(II), Ni(II) and Cu(II) derived from 2-thiophenecarboxylidene-3-chloro-4-fluoroaniline (TCC) and 2-thiophenecarboxylidene-4-fluoroaniline (TCF) have been synthesized by conventional as well as microwave methods. These compounds have been characterized by elemental analysis, ...
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The coordination complexes of Co(II), Ni(II) and Cu(II) derived from 2-thiophenecarboxylidene-3-chloro-4-fluoroaniline (TCC) and 2-thiophenecarboxylidene-4-fluoroaniline (TCF) have been synthesized by conventional as well as microwave methods. These compounds have been characterized by elemental analysis, FT-IR, FAB-mass, molar conductance, electronic spectra, ESR, thermal, magnetic susceptibility, electrical conductivity and XRD analysis. The complexes are coloured and stable in air. Analytical data revealed that all the complexes exhibited 1:2 (metal:ligand) ratio with the coordination 4 or 6. FAB-mass and thermal data show degradation pattern of the complexes. The thermal behavior of metal complexes shows that the hydrated complexes loses water molecules of hydration in the first step; followed by decomposition of ligand molecules in the subsequent steps. The crystal system, lattice parameter, unit cell volume and number of molecules in unit cell in the lattice of complexes have been determined by XRD analysis. XRD patterns indicate crystalline nature for the complexes. The solid state electrical conductivity of the metal complexes has also been measured. Solid state electrical conductivity studies reflect semiconducting nature of the complexes.
Kavita Verma; Seema Sharma; Dhananjay K Sharma; Raju Kumar; Radheshyam Rai
Abstract
Ba0.5Sr0.3TiO3 (BST 70/30) nanopowders have been prepared by the modified sol-gel method using barium acetate, strontium acetate and titanium isopropoxide as the precursor. The formation mechanism, phase evolution, and particle size have been investigated using TG/DTA, XRD, and SEM. The fine particles ...
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Ba0.5Sr0.3TiO3 (BST 70/30) nanopowders have been prepared by the modified sol-gel method using barium acetate, strontium acetate and titanium isopropoxide as the precursor. The formation mechanism, phase evolution, and particle size have been investigated using TG/DTA, XRD, and SEM. The fine particles of the nano-powders calcined are homogeneous and well-dispersed and their narrow size distribution is about 15–25 nm. The as-formed gel was dried at 2000 C and then calcined in the temperature range 6500 C to 8500 C for crystallization. Phase evolution during calcination was studied using X-ray diffraction (XRD) technique which exhibited cubic crystal structure with perovskite phase. Sintering of the pellet was performed at 9500 C and the study on the dielectric relaxation and the ac electrical conductivity behavior of modified Barium titanate, Ba0.5Sr0.3TiO3 ferroelectric ceramic exhibit that these are thermally activated process.
N.S. Dhoble; V.B. Pawade; S.J. Dhoble
Abstract
Eu 2+ luminescence in novel Sr3.5Mg0.5Si3O8Cl4 and Ba3.5Mg0.5Si3O8Cl4 phosphors is reported in this paper. These were synthesized by combustion method at 550 o C furnace temperature. The prepared phosphors shows PL emission spectra at 445 nm, due to 4f 6 5d 1 → 4f 7 transition of Eu 2+ ions by monitoring ...
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Eu 2+ luminescence in novel Sr3.5Mg0.5Si3O8Cl4 and Ba3.5Mg0.5Si3O8Cl4 phosphors is reported in this paper. These were synthesized by combustion method at 550 o C furnace temperature. The prepared phosphors shows PL emission spectra at 445 nm, due to 4f 6 5d 1 → 4f 7 transition of Eu 2+ ions by monitoring excitation at 358 nm for Sr and Ba host lattice. Phase purity was checked by using XRD-pattern. The prepared phosphors have potential applications for solid-state lighting purpose.
J.G. Mahakhode; S.J. Dhoble; S.V. Moharil
Abstract
One step combustion synthesis of preparation of plasma display panel (PDP) phosphors for X-ray induced luminescence is reported. The prepared phosphors were characterized by XRD, PL and X-ray excited luminescence (XEL) techniques. Phosphors emitting three primary colors have been be prepared by using ...
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One step combustion synthesis of preparation of plasma display panel (PDP) phosphors for X-ray induced luminescence is reported. The prepared phosphors were characterized by XRD, PL and X-ray excited luminescence (XEL) techniques. Phosphors emitting three primary colors have been be prepared by using the combustion synthesis. These may be used for X-ray imaging phosphors.
Roshani Singh; S.J. Dhoble
Abstract
Eu 3+ and Dy 3+ doped strontium vanadium oxide (Sr2V2O7) phosphor has been successfully synthesized using solid state diffusion method and characterized by XRD as well as photoluminescence (PL) measurements. The PL emission of Eu 3+ ion was observed in Sr2V2O7 phosphor at 593 nm and 618 nm in orange ...
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Eu 3+ and Dy 3+ doped strontium vanadium oxide (Sr2V2O7) phosphor has been successfully synthesized using solid state diffusion method and characterized by XRD as well as photoluminescence (PL) measurements. The PL emission of Eu 3+ ion was observed in Sr2V2O7 phosphor at 593 nm and 618 nm in orange and red region of the spectrum, which corresponds to 5 D0→ 7 F1, 5 D0→ 7 F2 transitions, at the excitation wavelength of 393 nm. The PL emission of Dy 3+ ion was observed in Sr2V2O7 phosphor at 484 nm and 575 nm in blue and yellow region of the spectrum, which corresponds to 4 F9/2→ 6 H15/2 and 4 F9/2 → 6 H13/2 transitions, at the excitation wavelength of 349 nm. The 300 – 400 nm is Hg free excitation, which is characteristic of solid state lighting. Hence, Sr2V2O7 :RE [RE = Eu 3+ and Dy 3+ ] phosphors may be efficient materials for solid state lighting.
Parag Nimishe; S.J. Dhoble
Abstract
In this paper we report the synthesis and luminescence of Dy 3+ activated tungstates of the type ALaLiWO6 (where A = alkaline earth metals Sr and Ba), prepared by solid state diffusion reaction method. These novel luminescent tungstate materials were characterized by X-ray diffraction, scanning electron ...
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In this paper we report the synthesis and luminescence of Dy 3+ activated tungstates of the type ALaLiWO6 (where A = alkaline earth metals Sr and Ba), prepared by solid state diffusion reaction method. These novel luminescent tungstate materials were characterized by X-ray diffraction, scanning electron microscope (SEM) and photoluminescence (PL) techniques. The Dy 3+ activated ALaLiWO6 (where A = Sr and Ba) phosphors are effectively excited around 350 nm which is mercury free excitation in near UV and give a broad emission band peaking around 470 nm(blue region) along with a sharp characteristic peak at 577 nm (yellow region). Thus, the Dy 3+ activated ALaLiWO6 phosphors may be used in white light applications.
K. Gao; S.M. Li; H.Z. Fu
Abstract
The orientation and deviation angle of intermetallic Al2Cu phase in directionally solidified Al-40wt. %Cu hypereutectic alloy were investigated using a rotating orientation X-ray diffraction (RO-XRD) method. Experimental results show that preferred planes (110) and (310) of the Al2Cu phase occur at 10 ...
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The orientation and deviation angle of intermetallic Al2Cu phase in directionally solidified Al-40wt. %Cu hypereutectic alloy were investigated using a rotating orientation X-ray diffraction (RO-XRD) method. Experimental results show that preferred planes (110) and (310) of the Al2Cu phase occur at 10 μm/s and the growth directions of the two planes are not well aligned with the heat flux direction. The growth direction of the preferred plane (110) has a 7.24 º~11.43 º angle with the heat flux direction. For the direction of the plane (310), its deviation angle attains 2.68 º ~ 20.82 º. Besides, the measured data agree well with the previously reported results, indicating that the RO-XRD method is an effective method for measuring the orientation and deviation angle of the phase in polycrystalline materials.
S.B. Raut; S.J. Dhoble; R.G. Atram
Abstract
A new blue emitting material containing quinoline is designed, synthesized and characterized. The material has been prepared by well-known reaction such as Friedlander condensation reaction at 140 °C. The blended thin films of Trichloro-DPQ with poly (methyl methacrylate) (PMMA) at different weight ...
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A new blue emitting material containing quinoline is designed, synthesized and characterized. The material has been prepared by well-known reaction such as Friedlander condensation reaction at 140 °C. The blended thin films of Trichloro-DPQ with poly (methyl methacrylate) (PMMA) at different weight % concentrations such as 10, 5, 1 and 0.1 weight % have been prepared. The structural characterization has been done by FTIR spectra. The synthesized polymeric compound demonstrates emission in blue region at 460 nm in powder form. At different weight % concentrations, there is emission at 444 nm with varying intensity. The light emitting and optoelectronic property of polymeric compound may find application in electroluminescence, OLED and sensors.
Sheo K. Mishra; Smriti Srivastava; Rajneesh K. Srivastava; A.C. Panday; S.G. Prakash
Abstract
In the present work, simple, low-cost, and direct route is used for the UV- photodetection and photoluminescent zinc-oxide nanoparticles (NPs) by decomposing zinc acetate in air at 400 0 C for 12 hrs. The X-ray diffraction (XRD) result indicates that the synthesized ZnO NPs is pure and single crystalline ...
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In the present work, simple, low-cost, and direct route is used for the UV- photodetection and photoluminescent zinc-oxide nanoparticles (NPs) by decomposing zinc acetate in air at 400 0 C for 12 hrs. The X-ray diffraction (XRD) result indicates that the synthesized ZnO NPs is pure and single crystalline structure with wurtzite type. The crystallite size of the ZnO nanoparticles is in the range of 20–50 nm and average crystallite size of synthesized nanoparticles is found to be ~33 nm. The synthesized ZnO NPs exhibits several photoluminescence peaks centered at 396 nm, 418 nm, 441 nm, 481 nm and 522 nm. The time-resolved rise and decay of photocurrent spectrum shows initial significant increase in photocurrent and, subsequently falls gradually under UV-illumination. The photocurrent abruptly falls when illumination is turned off. The variation of photo and dark-current with applied field is found to follow power-law i.e I α V. At low voltage the behavior is sub-linear which becomes super-linear at high voltages. The ZnO NPs is found to have double traps of 0.59 eV and 0.67 eV.
Faheem Ahmed; Shalendra Kumar; Nishat Arshi; Ram Prakash
Abstract
ZnO nanorods with diameter 90-100 nm range (tip diameter~15 nm) and length of about 2 μm have been prepared using microwave irradiation technique. X-ray diffraction (XRD) and transmission electron microscopy (TEM) results indicate that the nanorods have single phase nature with wurtzite structure ...
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ZnO nanorods with diameter 90-100 nm range (tip diameter~15 nm) and length of about 2 μm have been prepared using microwave irradiation technique. X-ray diffraction (XRD) and transmission electron microscopy (TEM) results indicate that the nanorods have single phase nature with wurtzite structure and preferentially grow along [0001] direction. Raman spectrum shows the mode E2 high at 439 cm −1 that is related to the vibration of oxygen atoms in wurtzite ZnO. Room-temperature ultraviolet-visible (UV-vis) absorption spectrum shows the absorption band at around 399 nm (red-shifted as compared to bulk). This novel nanostructure would be a promising candidate for a variety of future applications.
N.B. Dhokey; S. Ghule; K. Rane; R.S. Ranade
Abstract
Aluminium reinforced with TiB2 is an emerging class of metal matrix composites for many engineering applications such as automobiles, aerospace and naval vessels. The initial part of the present work study involves melting of individual fluxes of KBF4 and KTiF6 in premelted aluminium in an induction ...
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Aluminium reinforced with TiB2 is an emerging class of metal matrix composites for many engineering applications such as automobiles, aerospace and naval vessels. The initial part of the present work study involves melting of individual fluxes of KBF4 and KTiF6 in premelted aluminium in an induction furnace. In the later part of the work covers the combined effect of these fluxes to produce aluminium metal matrix composites containing 2.5% TiB2. The effect of the varying amount of KBF4 on kinetics of TiB2 formation and elimination other unstable phases was studied. The material was examined for hardness, microstructures and wear rates using Pin-on-Disc test machine, XRD and SEM-EDX analysis. The effect of TiB2 on properties was analysed. It was concluded that an optimum level of KBF4 is needed to get critical population of TiB2 particles in the matrix.
Abstract
Swift Heavy Ion (SHI) irradiation induces chemical and structural changes in polymers by evolving various gases and gaseous fragments. The evolution of gases as a result of chain scissoring and bond breaking leads to cross-linking and cluster formation. Study of the evolved gases helps in understanding ...
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Swift Heavy Ion (SHI) irradiation induces chemical and structural changes in polymers by evolving various gases and gaseous fragments. The evolution of gases as a result of chain scissoring and bond breaking leads to cross-linking and cluster formation. Study of the evolved gases helps in understanding the various chemical and structural changes occurring within the polymer under the effect of SHI irradiation. In the present work, Poly (o-toluidine) (PoT), a derivative of polyaniline, is prepared by chemical oxidation polymerization and is blended with polyvinylchloride (PVC) to achieve self supported films. These PoT-PVC blend films were irradiated by 60 MeV Si 5+ ions at different fluences and evolved gases were monitored on-line by Residual Gas Analyzer (RGA). Pre and post irradiation FTIR, UV-Visible absorption and XRD studies have been carried out on these films to observe the changes in chemical/structural and optical properties. An effort has been made to correlate the evolved gases and structural properties after irradiation.Copyright © 2011 VBRI press.
