2013-14

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Browsing 2013-14 by Subject "Photoluminescence"

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    Low temperature synthesis and photoluminescence properties of redemitting Mg2SiO4:Eu3+nanophosphor for near UV light emittingdiodes
    (2014-03-13T10:17:32Z) Ramachandra, Naika; Prashantha, SC; Nagabhushana, H; Sharma, SC; Nagabhushana, BM
    tA simple and low-cost solution combustion method was used to prepare Eu3+(1–11 mol%) doped Mg2SiO4nanophosphors at 350◦C using metal nitrates as precursors and ODH (Oxali di-hydrazide) as fuel. Thefinal products were well characterized by powder X-ray diffraction (PXRD), fourier transform infraredspectroscopy (FTIR), scanning electron microscopy (SEM) and UV–visible absorption (UV–Vis). The PXRDpatterns of the as-formed products show single orthorhombic phase. The crystallite size was estimatedusing Scherrer’s method and found to be in the range 20–25 nm. The effect of Eu3+cations on the lumi-nescence properties of Mg2SiO4:Eu3+nanoparticles were understood from the luminescence studies.The phosphors exhibit bright red emission upon 393 nm excitation. The characteristic emission peaksrecorded at ∼577, 590, 612, 650 and 703 nm (5D0→7FJ=0,1,2,3,4) were attributed to the 4f–4f intra shelltransitions of Eu3+ions. The intensity of red emission was found to be related with the concentration ofintrinsic defects, especially oxygen-vacancies, which could assist the energy transfer from the Mg2SiO4host to the Eu3+ions. The Commission International De I-Eclairage (CIE) chromaticity co-ordinates werecalculated from emission spectra, the values (x,y) were very close to National Television System Commit-tee (NTSC) standard value of red emission. Therefore, the present phosphor was highly useful for displayapplications.