S. Rajesh; K. Thyagarajan; Vasudeva Reddy Minnam Reddy
Abstract
Zinc Sulfide nanophosphor (ZnS) nanophosphor doped with 2 mol % Dysprosium (Dy) and co-doped with (2 – 6) mol % Manganese (Mn) was successfully prepared by cost-effective chemical co-precipitation method using polyvinylpyrrolidone (PVP) as the capping agent. The effects of dopant and co-dopant ...
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Zinc Sulfide nanophosphor (ZnS) nanophosphor doped with 2 mol % Dysprosium (Dy) and co-doped with (2 – 6) mol % Manganese (Mn) was successfully prepared by cost-effective chemical co-precipitation method using polyvinylpyrrolidone (PVP) as the capping agent. The effects of dopant and co-dopant concentrations on the various properties of ZnS were investigated by various characterizations like Powder X-ray Diffraction (PXRD) studies confirmed the cubic zinc blende structure of ZnS and no impurity peaks corresponding to Dy doping and Co-doped by Mn was observed. Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDAX) confirmed the presence of dopant Dy and co-dopants Mn in the prepared ZnS. Photoluminescence (PL) studies on Dy doped Mn and co-doped ZnS nanophosphor indicated that the emission wavelength 605 nm is tunable in the range of 400–650 nm with the incorporation of doped Dy and Co-doped Mn into ZnS host lattice with the excitation wavelength of 320 nm. Blue color of ZnS doped Dy by enhances to orange color due to co-doped with Mn ions. The chromaticity co-ordinates (CIE) and Correlated color temperature (CCT) of the phosphor were shows enhancement of blue to orange region; hence, it is useful for the fabrication of orange component of WLEDs and display applications. Copyright © 2018 VBRI Press.
S. M. Sathiya; G. S. Okram; M. A. Jothi Rajan
Abstract
Microwave assisted co-precipitation method is used to synthesize copper oxide nanoparticles from various concentrations of CuCl2.2H2O (0.1 M - 0.5 M) precursors. Both CuO and Cu2O phases are observed from X-ray diffraction (XRD) pattern and further confirmed from Energy Dispersive X-ray Analysis (EDX) ...
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Microwave assisted co-precipitation method is used to synthesize copper oxide nanoparticles from various concentrations of CuCl2.2H2O (0.1 M - 0.5 M) precursors. Both CuO and Cu2O phases are observed from X-ray diffraction (XRD) pattern and further confirmed from Energy Dispersive X-ray Analysis (EDX) and selected area electron diffraction (SAED) data. The particle size of 43 to 27 nm determined from XRD data using Scherrer formula is in good relation with Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) images. The existence of reasonably uniform size and shape is clear from SEM. The band gaps determined from the UV-Visible absorption peaks and vibrational modes observed from Micro-Raman Scattering (MRS) analysis further confirm the presence of CuO and Cu2O phases. These results are also related to electrical conductivity at low temperatures which illustrate different types of conduction mechanisms. The samples show semiconducting behavior with improved electrical conductivity. Finally, the material is proposed to have applications in designing gas sensors and also in regulating electrical conductivity in drug delivery systems. Copyright © 2017 VBRI Press.
Azizurrahaman Ansari; Vishal Kumar Chakradhary; M. J. Akhtar
Abstract
In this article, an effort is made to synthesize the nickel ferrite nanoparticles via chemical co-precipitation method using the metal nitrates as precursors. The x-ray diffraction pattern of the as-synthesized powder sample indicates the formation of nickel ferrite with iron oxide and other impurity ...
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In this article, an effort is made to synthesize the nickel ferrite nanoparticles via chemical co-precipitation method using the metal nitrates as precursors. The x-ray diffraction pattern of the as-synthesized powder sample indicates the formation of nickel ferrite with iron oxide and other impurity phases. The heat treatment of the as-synthesized powder at 600oC assists in the formation of inverse spinel phase of nickel ferrite accompanying with some fraction of iron oxide phase. The field emission scanning electron microscopy of the heat treated sample reveals the irregular particle size and shape with fine microstructures, while as-synthesized sample shows the lamina like particle morphology. The magnetization curve(M-H curve) of the heat treated sample shows the ferrimagnetic behavior with very small (negligible) values ofremanent magnetization and coercive field. Such type of magnetic characteristic indicates the signature of superparamagnetism (Mr ~ 0, Hc ~ 0) in the heat treated nickel ferrite nanoparticles with significant value of the saturation magnetization (Ms). The superparamagnetic effect in the nickel ferrite particles has great potential in the field of biomedicine for certain applications such as the effective drug delivery, and for enhancing the contrast in case of magnetic resonance imaging. Copyright © 2016 VBRI Press.
