Properties of SiAlON powder phosphors for white LEDs

Three kinds of Eu2+-doped oxynitride powder phosphors, including green β-SiAlON, yellow Ca-α-SiAlON and newly developed orange Ca-α-SiAlON were prepared by gas pressure sintering, which emit the fluorescent light with emission peak at 540 nm, 585 nm and 597 nm, respectively. Emission intensity more than 90% can be kept in the range of temperature from 30 °C to 200 °C. Emission characteristics are stable after long-term exposure testing for 6000 h at temperature of 85 °C and in humidity of 85%. A white LED device composed of a blue LED chip, β-SiAlON and orange Ca-α-SiAlON phosphors exhibits a modest colour rendering index of 72.