Rapid-gel combustion synthesis, structure and luminescence investigations of trivalent europium doped MGdAlO4 (M = Mg2+, Ca2+, Sr2+ and Ba2+) nanophosphors

Abstract A series of novel red MGdAlO4:Eu3+ (M = Mg2+, Ca2+, Sr2+ and Ba2+) was synthesized and investigated. The samples were synthesized via rapid-gel combustion route at a temperature of 600 °C and examined over large doping concentration of 0.01 to 0.05 moles. The optimal concentration of activator ion has been found to be 0.03 moles for MGdAlO4 lattice. Using the excitation wavelength of 393 nm, these phosphors exhibited strong emission in the red region owing to 5D0→7F2 (electric dipole allowed) transition located at 610-615 nm. The effect of reaction temperature on luminescence was also analyzed for these materials. The structural characteristics of phosphors were studied via joint approach of X-ray diffraction (XRD) and Transmission electron microscopy (TEM). Diffraction patterns of prepared phosphor contain sharp peaks in 10°-80° region. The proposed materials have single phase tetragonal structure having I4/mmm space group. The degree of crystallization has been found to increase with temperature. The TEM micrographs exhibited the spherical shape of particles in 15-35 nm size. The FTIR spectra of CaGdAlO4 showed peaks at 699 and 461 cm-1 analogous to Al-O and Gd-O stretching vibrational modes. Due to excellent luminescent response the Eu3+ doped MGdAlO4 can be excellent materials for the growth of effective red phosphor in WLEDs and fluorescent panels.