One-step preparation of Ca-α-SiAlON:Eu2+ fine powder phosphors for white light-emitting diodes

A simple methodology for producing yellow-emitting Ca-α-SiAlON:Eu2+ phosphors for white light-emitting diodes has been developed, which consists of postsynthesis activation of fine α-SiAlON powders prepared by the gas-reduction-nitridation method. Phase-pure, fine Ca-α-SiAlON:Eu2+ phosphors possessing the particle size ranging ∼0.9–2.8μm and high quantum efficiencies of ∼44%–55% under near-UV to blue light excitation are obtained as the process developed. The chromaticity coordinate of the synthesized Ca-α-SiAlON:Eu2+ can be tailored by simply controlling the activator concentration, enabling the creation of a broad range of warm-white light with the correlated color temperatures of ∼3500–2600K.