The Debye temperature as well as the Grünesien parameter for each concentration are predicted. The overall anisotropy shows a very small increase with increasing concentration. The overall shear, bulk, and Young’s moduli exhibit a decreasing trend with increasing Eu3+ concentration. The results show that the Eu3+ ions primarily occupy the Y1 site of the basic molecule for all applied concentrations. The model is based on a low temperature approximation (T<<θD), and the plane-wave density functional theory (DFT) is used to carry out the calculations. We investigate the variation of elastic stiffness moduli and the thermodynamic properties of yttrium orthosilicate (Y2SiO5, YSO) under various doping concentrations of Eu3+ ions. The prepared samples are expected to be suitable candidates for the applications as solid state devices, lighting and optical displays.
Time resolved fluorescence spectra were carried out to determine the decay lifetime of the samples. In addition, Judd-Ofelt (JO) parameters (Ω2, Ω4) and other derived radiative parameters were calculated using Judd-Ofelt theory from the PL emission spectra. The photometric parameters correlated color temperature (CCT), color rendering index (CRI) and color purity (CP) were computed using CIE chromaticity co-ordinate diagram. The concentration quenching and energy transfer mechanisms were elucidated by Blasse and Dexter's formula. The highest emission peak was observed at 595 nm which corresponds to the ⁵D0 → ⁷F1 transition of Eu³⁺ ions with selection rule ΔJ = 1. The emission spectra recorded under the excitation wavelength λex = 396 nm. The luminescent properties of prepared samples were studied by photoluminescence (PL) and thermoluminescence (TL) characteristics. The vibrational and bonding behavior of silicate groups were confirmed by Fourier transform infrared (FTIR) and Raman spectroscopy. Phase structure and phase purity of sample were investigated by Rietveld refinement method. Their structural and morphological studies were investigated by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) measurements.
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A series of Eu³⁺ doped calcium magnesium silicate (CaMgSiO4) phosphor samples were successfully prepared via solid state synthesis technique.
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