Improved thermal quenching of Y3Al5O12:Ce phosphor ceramics with silica addition

Y3Al5O12:Ce (YAG:Ce) is widely used in light emitting diodes (LEDs) for the conversion of blue light into yellow light. However, thermal quenching has become a severe problem for high-power LEDs because more heat is generated by high-power LED chips; this results in the reduction of emission intensity and unit life. In this research, silica was fired with co-precipitated YAG:Ce phosphor ceramics to study the photoluminescent thermal quenching behavior by comparing with pristine YAG:Ce. The results showed that silica-added YAG:Ce phosphor ceramics exhibited an increase of more than 15% in quantum efficiency and a higher thermal quenching temperature compared with pristine YAG:Ce. This improvement in thermal stability (10% increase at 150 °C) in silica-added YAG:Ce phosphor ceramics was attributed to a denser microstructure and an increase in thermal activation energy by Si substitution of Al in the host.