Synthesis of red-emitting, small particle size luminescent oxides using an optimized combustion process

A novel ceramic synthesis technique, combustion synthesis, was explored to produce red-emitting Cr3+-doped Y3Al5O12 and Eu3+-doped Y2O3 phosphors with improved physical and luminescent properties, This technique involves the reaction of metal nitrates (oxidizers) and an organic fuel (urea, carbohydrazide, glycine) at 500 degrees C. Resulting powders are well-crystallized, with a large surface area and small particle size, The spectral energy distribution was observed using photoluminescence measurements, The effects of processing parameters such as type of fuel, fuel-to-oxidizer ratio, furnace temperature, and batch water content were studied, An increase in phosphor brightness with increasing reaction temperature was observed, Postreaction heat treatments (1000 degrees, 1300 degrees, and 1600 degrees C) increased the luminous intensity of as-synthesized powders, Residual carbon content and chromium site symmetry were investigated as possible explanations for the increase in brightness with increasing heat treatment temperature, By tailoring the reaction chemistry, the optimal conditions for producing the most luminescent phosphors have been identified.