Eu(2+)-activated silicon-oxynitride Ca(3)Si(2)O(4)N(2): a green-emitting phosphor for white LEDs

Abstract

The green-emitting phosphor Ca(3)Si(2)O(4)N(2):Eu(2+) was synthesized using a solid-state reaction. The luminescence properties, diffuse reflection spectrum, and thermal quenching were firstly studied, and a white light-emitting diode (wLED) was fabricated using the Eu(2+)-activated Ca(3)Si(2)O(4)N(2) phosphor. Eu(2+)-doped Ca(3)Si(2)O(4)N(2) exhibited a broad green emission band centered between 510 and 550 nm depending on the concentration of Eu(2+). The optimal doping concentration of Eu(2+) in Ca(3)Si(2)O(4)N(2) was 1 mol%. The energy transfer between Eu(2+) ions proceeds by an electric multipolar interaction mechanism, with a critical transfer distance of approximately 30.08 angstrom. A wLED with an color-rendering index R(a) of 88.25 at a correlated color temperature of 6029 K was obtained by combining a GaN-based n-UV LED (380 nm) with the blue-emitting BaMgAl(10)O(17):Eu(2+), green-emitting Ca(3)Si(2)O(4)N(2): Eu(2+), and red-emitting CaAlSiN(3):Eu(2+) phosphors. The results present Ca(3)Si(2)O(4)N(2):Eu(2+) as an attractive candidate for use as a conversion phosphor for wLED applications. (C) 2011 Optical Society of America