A CaS:Eu based red-emitting phosphor with significantly improved thermal quenching resistance for LED lighting applications

Abstract

While CaS:Eu based system can be much needed low-cost red emitting phosphors for LED lighting applications, their poor thermal quenching resistance remains an issue. In this work we have investigated the effect of adding small amount of Mg and Ga on the emission intensity of CaS:Eu at room and elevated temperatures. We found that the addition of small amount of Mg and Ga at the same time to substitute Ca leads to a significant improvement in the photoluminescence efficiency of CaS:Eu at both room and elevated temperatures. We reported that a new red-emitting phosphor of Ca0.89Mg0.01Ga0.1S:Eu can reduce the drop of its emission intensity with rising temperature by as much as 37 percentage points as compared to undoped CaS:Eu at 185°C. Its emission intensity at room temperature is also 23.9% higher than that of undoped CaS:Eu.