Low temperature ammonothermal synthesis of europium-doped SrAlSiN₃: effect of mineralizers

Abstract

SrAlSiN₃:Eu²⁺ is a red-emitting phosphor that is potentially very useful in white light-emitting diodes because of its properties such as thermal stability and bright emissivity features. A limitation of this phosphor is that it is commonly synthesized at high temperature (2173 K) and pressure (190 MPa). To address this limitation, we report (1) a low-temperature (1073 K) synthesis of SrAlSiN₃:Eu²⁺ phosphors through a dissolution–precipitation process in supercritical ammonia (ammonothermal method) and (2) an investigation of the phosphors’ physical properties. All products exhibit a broad emission that is centered at approximately 580 nm, which we attribute to the 5d→4f transition of Eu²⁺, under excitation wavelengths from the ultraviolet to blue range. We used Sr as a mineralizer to synthesize a superior product in terms of a high Sr concentration in the crystals, improved crystallinity, and enhanced emission intensity.