Nitride and oxynitride phosphors for white LEDs: Synthesis, new phosphor discovery, crystal structure

Si,Al containing nitride and oxynitride phosphors have been applied to white LEDs. Phosphors play important roles to produce high color rendering in lighting and wide color gamut in display. Si,Al containing nitrides and oxynitrides have been studied as high-temperature materials with high strength and thermal shock resistance. The inherited high temperature property is utilized as low thermal quenching in luminescence. The increased covalent bonding character compared to oxide phosphors contributes to high efficiency in blue excitation. The crystal structure (especially the coordination sphere around luminescent center) dominates the luminescent property of phosphor. Wide variety of crystal structure in Si,Al containing nitride and oxynitride leads to multiplicity of luminescent property. In this contribution, Si,Al containing nitride and oxynitride phosphors are reviewed from viewpoints of synthesis, new phosphor discovery, and crystal structure.