Blue-shift of spectrum and enhanced luminescent properties of YAG: Ce3+ phosphor induced by small amount of La3+ incorporation

• Blue-shift of spectrum was observed by La3+ co-doping YAG: Ce3+ phosphor.
• Luminescent properties were enhanced by appropriate amount of La3+ addition.
• The mechanism was ascribed to the effect of La3+-Ce3+ gathering.
• This effect is expected to be occurred in other garnet phosphor systems as well.

A gradual blue-shift of spectrum in YAG: Ce3+ phosphor induced by small amount of La3+ co-doping was observed. The luminescent efficiency and thermal quenching properties were enhanced by appropriate amount of La3+ incorporation. The possible mechanism of these changes in luminescent properties was investigated by luminescence dynamics analysis and first principles calculation on structure optimization. The results demonstrate that the local structural variation around Ce3+ ions may be responsible for the blue-shift of spectrum and enhanced luminescent properties, which produces a relatively stable environment for Ce3+ ions and prevents concentration quenching. The above results indicate that appropriate amount of La3+ co-doing is beneficial to luminescent properties enhancement of YAG: Ce3+ phosphor and it is expected to be extended in other Ce3+-activated garnet phosphors.