Properties and synthesis of morphology-controllable CaAl12O19: Mn4+ by combustion synthesis

A red phosphor CaAl12O19: Mn4+ was prepared utilizing the redox of metal nitrates and urea by combustion synthesis with ignition temperature of 700°C. This phosphor can be used in white LED. The shape and surface morphology of the phosphor were controlled by changing the dosage of ammonium nitrate (NH4NO3). The samples were characterized with x-ray diffraction (XRD), scanning electron microscopy (SEM) and Fluorescence spectrometer. The results indicate that CaAl12O19: Mn4 phosphor particles show patch or needle shapes in different reaction conditions. The formation mechanism was also discussed. The CaAl12O19:Mn4+ phosphor had a better optimum crystallinity and luminescence properties when mole ratio between NH4NO3 and urea was given in 1:2.