Combustion Synthesis of Hexaaluminate Phosphors

Green phosphors of the composition Ce 1‐ x Tb x MgAl 11 O 19 (0.1 < x < 0.6) were prepared via self‐propagating (combustion) synthesis, using urea as a fuel. The phosphors that were produced via the combustion route were fine powders and produced a luminous intensity of 72%, compared to an optimized commercial phosphor. The excitation spectra were characteristic of the Ce 3+ cation; however, no Ce 3+ emission was observed. Energy transfer from the Ce 3+ cation to the Tb 3+ cation was complete, and only the 542 nm Tb 3+ emission was observed. Concentration quenching occurred with x > 0.5. Scanning electron microscopy images showed a well‐crystallized, platelike morphology, with a particle size of 10‐20 µm.