Jing Niu

A New Route to Synthesize β-SiAlON:Eu2+ Phosphors for White Light-Emitting Diodes

A simple, highly efficient method of synthesizing β-SiAlON:Eu2+ phosphors for white light-emitting diodes was reported. The new route was carried out via a combustion synthesis method using Si, SiO2, and Al raw materials, and NaCl as a diluent under nitrogen pressure. The phase purity, photoluminescence properties, and thermal quenching of the phosphors were investigated. The results revealed that the synthesized β-SiAlON:Eu2+ powders, which comprised rodlike crystals, exhibited high thermal stability: The emission intensity at 160 °C was 84% of that measured at room temperature, which indicates that the synthesized β-SiAlON:Eu2+ phosphors have high potential for application to white LEDs.

Thermodynamics Analysis on Combustion Synthesis of β-SiAlON

Combustion synthesis (CS) of β-SiAlON (z = 1) was carried by heating the raw mixtures of Si, Al, and SiO2 under a constant nitrogen pressure of 1 MPa to the preconcerted temperature. The temperature profile was recorded by a W-Re thermocouple, which showed several exothermic and endothermic reactions during the entire CS process. The maximum temperature reached above 1900°C, and two main exothermic reactions at ~800 °C and ~1350 °C were found. The XRD analyses indicated that the main intermediate products are AlN, SiO2, and Al2O3 before β-SiAlON was synthesized finally. From our analyses, Al reacted with nitrogen gas at ~800 °C first, then at ~1350 °C, the main reaction occurred and the final product was obtained synchronously.