Exploring a particle-size-reduction strategy of YAG:Ce phosphor via a chemical breakdown method

Particle size reduction of Y3Al5O12:Ce (YAG:Ce) phosphor is highly needed for micro-LED display applications. In this work, size control of YAG:Ce phosphor particles is achieved via carbon coating and further heat treatment. A thin layer of carbon is deposited on the surface of YAG:Ce by chemical vapor deposition. During the heat treatment, carbon reacts with oxygen element in the phosphor and escapes from phosphor particles. The reaction results in the phosphor breaking into smaller particles. The phosphors were characterized by laser light scattering for particle size distribution, scanning electron microscopy (SEM), transmission electron microscopy for morphologies, X-ray diffraction refinements for crystal structure and electron energy-loss spectroscopy for elemental analysis. It is demonstrated that the median diameter (D50) of the phosphor particle size is significantly reduced from 19.1 to 0.96 μm yet the photoluminescent properties have little changes. The carbon coating and further heat treatment method show potential application in size control of phosphors.