Sol–gel synthesis, growth mechanism and luminescence properties of uniform Ce0.67Tb0.33MgAl11O19 phosphor

Ce0.67Tb0.33MgAl11O19 (CMAT) green phosphors with variety of morphologies have been successfully prepared via a sol–gel method. The crystalline structure, morphology, and luminescent properties of these phosphors were characterized using powder X-ray diffraction (XRD), scanning electron microscopy (FE-SEM), and photoluminescence (PL) spectroscopy. The XRD patterns showed that the samples can be well-crystallized at 1300 °C. The FE-SEM images revealed that the morphology and size distribution of the synthesized CMAT phosphor were predominantly dependent upon the pH value and molecular weights of polyethylene glycol in the initial reaction systems, and the morphologies of the particles vary from irregular to spherical then to hexagonal flake shape by decreasing the acidity of the solution in the range of pH = 2–8. The PL properties were discussed in terms of crystallinity, particle size and shape of the as-obtained phosphors. A reasonable explanation for the shape modifier on the morphology of CMAT has been presented.