Green light-emitting Lu3Al5O12:Ce phosphor powders prepared by spray pyrolysis

Abstract

Green light-emitting Lu2.985Al5O12:Ce0.015 (LuAG:Ce) phosphor powders are prepared by spray pyrolysis. The only crystallized phase in the precursor powders and post-treated powders at temperatures below 800°C is Lu2O3 and the other components are amorphous. Phase pure cubic garnet LuAG:Ce phosphor powders are obtained by post-treatment at 1000°C. Phosphor powders post-treated at temperatures below 1400°C retain the spherical shape of the precursor powders. The mean crystallite sizes of phosphor powders post-treated at 1200, 1400, and 1500°C are 30, 46, and 54nm, respectively. The excitation spectra contain two bands: a weak band with the maximum peak at 345nm and a strong broad band in the spectral range from 400 to 490nm with the maximum peak at 455nm. The LuAG:Ce phosphor powders have broad emission spectra between 480 and 600nm, with the maximum peak intensity located at 507nm. The photoluminescence intensity of the phosphor powders post-treated at 1400°C is 84.2% of that of the powders post-treated at 1500°C.