Synthesis, structure and photoluminescent characterization of MYAl_3O_7:Eu~(3+) (M=Ca, Sr, Mg and Ba) red emitting materials for display applications

摘要

MYAl3O7:Eu3+ (M=Ca, Sr, Mg and Ba) materials were synthesized via combustion method at 600 A degrees C temperature. These materials were further given two heat treatments at 900 and 1050 A degrees C for 2 h each to demonstrate the consequences of higher temperature on emission intensity and crystal assembly. The optimal concentration of activator ion in CaYAl3O7 lattice was 0.03 mol. The prepared phosphors were characterized with different techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and photoluminescence (PL). XRD spectra showed CaYAl3O7 phosphor was of tetragonal symmetry with P42(1) m space group. Particle size of the proposed materials was also calculated by this technique using Scherer's equation. Chemical bonding, mainly metal-oxygen bonds were explained by FTIR technique. TEM analysis was used to study the three dimensional structure as well as to estimate the size of particles (55-70 nm). At 254 nm excitation wavelength, these were found to be strong red emitters due to typical D-5(0) -> F-7(2) (forced electric dipole) transition at 610-616 nm. Their PL spectra were also having some weak emission bands viz. D-5(0) -> F-7(1) (magnetic dipole) transition located at 587-591 nm and D-5(0) -> F-7(3) transition at 650-655 nm. The nano size of the phosphors had made them suitable for a variety of display applications.