Low temperature ammonothermal synthesis of europium-doped SrAlSiN₃ for a nitride red phosphor

Abstract

Because of its use as a mother crystal of red phosphor in white LEDs, SrAlSiN₃ is a very interesting complex nitride. Till date, the only examples of europium-doped SrAlSiN₃ synthesis have been in high-pressure nitrogen atmospheres at high temperatures above 2000 K at 190 MPa with typical solid-state reaction. In comparison, our research is the first to achieve such synthesis at an extremely low temperature of 773 K at 100 MPa. In addition, we document the first instance of synthesis using supercritical ammonia fluid with NaNH₂ as a reaction medium. Moreover, to our knowledge, this report details the first instance of synthesis of europium-doped SrAlSiN₃ by using dissolution and precipitation reaction. Reaction temperature and time dependencies of ammonothermal reactions for the product are investigated. The obtained product exhibits a red emission by irradiation of blue light of 460 nm.