B. Eraiah

Thermoluminescence and EPR studies of nanocrystalline Nd2O3:Ni2+ phosphor

Nanocrystalline Nd(2)O(3):Ni(2+) (2 mol%) phosphor has been prepared by a low temperature (∼400°C) solution combustion method, in a very short time (<5 min). Powder X-ray diffraction results confirm the single hexagonal phase of nanopowders. Scanning electron micrographs show that nanophosphor has porous nature and the particles are agglomerated. Transmission electron microscopy confirms the nanosize (20-25 nm) of the crystallites. The electron paramagnetic resonance (EPR) spectrum exhibits a symmetric absorption at g≈2.77 which suggests that the site symmetry around Ni(2+) ions is predominantly octahedral. The number of spins participating in resonance (N) and the paramagnetic susceptibility (χ) has been evaluated. Raman study show major peaks, which are assigned to F(g) and combination of A(g)+E(g) modes. Thermoluminescence (TL) studies reveal well resolved glow peaks at 169°C along with shoulder peak at around 236°C. The activation energy (E in eV), order of kinetics (b) and frequency factor (s) were estimated using glow peak shape method. It is observed that the glow peak intensity at 169°C increases linearly with γ-dose which suggest that Nd(2)O(3):Ni(2+) is suitable for radiation dosimetry applications.

Structural, EPR, optical and Raman studies of Nd2O3:Cu2+ nanophosphors

Nanocrystalline Nd(2)O(3):Cu(2+) (2mol %) phosphors have been prepared by a low temperature solution combustion technique. Powder X-ray diffraction (PXRD) results confirm that hexagonal A-type Nd(2)O(3) (900°C, 3h) and the lattice parameters have been evaluated by Rietveld refinement. Surface morphology of as-formed and Cu(2+) doped Nd(2)O(3) phosphors show that the particles are irregular in shape and porous in nature. TEM results also confirm the nature and size of the particles. The EPR spectrum exhibits two resonance signals with effective g values at g(ǀǀ)≈2.12 and g(⊥)≈2.04. The g values indicate that the site symmetry of Cu(2+) ions is octahedral symmetry with elongated tetragonal distortion. Raman studies show major peaks, which are assigned, to F(g) and combination of A(g)+E(g) modes. It is observed that the Raman peaks and intensity have been reduced in Cu(2+) doped samples. UV-Visible absorption spectra exhibit a strong and broad absorption band at ∼240nm. Further, the absorption peak shifts to ∼14nm in Cu(2+) doped samples. The optical band gap is estimated to be 5.28eV for Cu doped Nd(2)O(3) nanoparticles which are higher than the bulk Nd(2)O(3) (4.7eV). This can be attributed to the quantum confinement effect of the nanoparticles.

Green Synthesis, Characterization and Antibacterial Activity of CuO Nano Particle

A green low temperature combustion route is proposed for the synthesis of CuO nanoparticles, using Copper nitrate powder and Nigella sativa (Kalonji) seed extract as the starting materials. The formation of CuO Nps was characterized by PXRD, SEM, UV-Visible etc. The PXRD Pattern reveals that as-synthesized CuO Nps of monoclinic phase and Crystallite structure. The scanning electron microscopy (SEM) images reveal the morphology of the nanoparticles are spherical in shape. CuO Nps show significant antibacterial activity against both gram +ve and Gram-ve bacterial strains using agar well diffusion method. The present method brings out a promising green, simple, low cost and low temperature way to prepare multifunctional CuO nanomaterials.

Elastic properties of silver borate glasses doped with praseodymium oxide

A series of glasses xPr6O11−(35−x) Ag2O−65B2O3 with x=0, 0.1, 0.2, 0.3, 0.4 and 0.5 mol % were synthesized by melt quenching technique. Longitudinal and shear ultrasonic velocity were measured at 5 MHz frequency and at room temperature. Elastic moduli, Poissons ratio and Debye temperature have been calculated from the measured density and ultrasonic velocity at room temperature. The experimental results indicate that the elastic constants depend upon the composition of the glasses. The role of the Pr6O11 inside the glass network was discussed.

Influence of europium (Eu3+) ions on the optical properties of boro tellurite glasses

The influence of Eu3+ ions on the Optical properties of Boro Tellurite Glasses of (70-x) B2O3−15TeO2−10Na2O− 5PbO-xEu2O3 with x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5 mol% glasses were prepared by convent...

Dy3+ doped cubic zirconia nanostructures prepared via ultrasound route for display applications

White light emitting dysprosium (Dy) doped Zirconia (ZrO2) nanostructures were prepared first time via ultrasound assisted sonochemical synthesis route using cetyltrimethylammonium bromide (CTAB) surfactant. The obtained product was well characterized. The powder X-ray diffraction (PXRD) profiles confirmed that the product was highly crystalline in nature with cubic phase. Various reaction parameters such as, effect of sonication time, concentration of the surfactant was studied in detail. Diffuse reflectance spectroscopy (DRS) was studied to evaluate the band gap energy of the products and the values were found in the range of 4.13 – 4.53 eV. The particle size was estimated by transmission electron microscope (TEM) and it was found in the range of 10-20 nm. Photoluminescence (PL) properties were studied in detail by recording emission spectra of all the Dy doped Zirconia nanostructures at an excitation wavelength of 350 nm. The emission peaks were observed at 480, 574 and 666 nm which corresponds to Dy3+...

Electrical properties of praseodymium oxide doped Boro-Tellurite glasses

Glasses of the composition xPr6O11- (35-x)TeO2-65B2O3 (x=0, 0.1 to 0.5 mol %) have been prepared using the melt quenching method. The ac and dc conductivity of glass have been measured over a wide range of frequencies and temperatures. Experimental results indicate that the ac conductivity depend on temperature, frequency and Praseodymium content. The conductivity as a function of frequency exhibited two components: dc conductivity (σdc), and ac conductivity (σac). The activation energies are estimated and found to be decreases with composition. The impedance plot at each temperature appeared as a semicircle passes through the origin.

Synthesis and structural studies of praseodymium doped silver borate glasses

Praseodymium doped silver borate glasses with nominal composition xPr6O11−(25−x)Ag2O−75B2O3 (x=0, 1, 2, 3, 4, 5) were prepared by melt quench technique. XRD pattern shows that there is no sharp peak it confirms the amorphous nature of the present glasses. The glass transition temperature (Tg) of this glass system have been studied using the Matac MBS-8000 Digital Signal Processing and Conventional Thermal Analysis (DTA) method. The Tg of these glasses increases with increase in concentration of Pr6O11 except at 0.2 mol%, Tg value is lower. 11B MAS-NMR shows the presence of sharp peak around 0.306 ppm. Chemical shift of these glasses decreases with mol% of rare earth oxide. FTIR spectra recorded in the region of 400 to 4000 cm−1. This studies revealed that the progressive addition Ag2O and Pr6O11 leads to modification of B2O3 into BO4 groups. Raman measurements of these glasses support the proposed interpretations of the experimental results.

Preparation and properties of silver-borate glasses doped with praseodymium oxide

Silver-borate glasses doped with Praseodymium oxide having composition xPr6O11-(25-x)Ag2O-75B2O3 (x = 0,1,2,3,4,5mol%) were prepared by conventional melt quenching method. The density, molar volume, and optical energy band gap of these glasses have been measured. Optical absorption spectra of these glasses were recorded in the range 300-1000 nm at room temperature. The optical energy band gap obtained in the present work is 1.9531eV to 2.4166 eV.