Ce-doped YAG phosphor powder synthesized via microwave combustion and its application for white LED

Cerium-doped yttrium aluminum garnet (YAG  :  Ce3  +  ) powder phosphor have been extensively studied as phosphors for blue to white light conversion. Y(3  −  x)Al5O12  :  x Ce3  +   (x  =  2.0 at. %) were successfully synthesized by microwave-assisted combustion (MW) using the organic fuel urea. A direct conversion from the amorphous phase to the cubic one was obtained at 1050°C for 5 h, together with an increase in the particle size into the range of 50 to 60 nm and decrease in the specific surface area. The as-prepared precursors and powder sintered at 1050°C were characterized for their structure, particle size, morphology, electroluminescence properties, and chromaticity by x-ray diffraction, Brunauer–Emmett–Teller method, Fourier transform infrared spectroscopy, field emission-scanning electron microscopy, transmission electron microscopy, electroluminescence, and standard CIE 1931 chromaticity analysis (CIE) chromaticity diagram, respectively. The results show that the obtained sintered YAG  :  Ce3  +   phosphor powder has spherical-shaped particles and strong yellow emission compared to as-prepared phosphor powder. White light emitting diodes with proper color rendering index, and tunable correlated color temperature properties can be produced by controlling the injection currents and coating thickness of the sample, offering daylight white and neutral white LEDs.