Powder synthesis and luminescence properties of green emitting Ba2LiSi7-xAlxN12-xOx:Eu2+ phosphor

Highlights: • Preparation of single phase powders of green emitting Ba₂LiSi_7-xAl_xN_12-xO_x:Eu²⁺ phosphor. • The integrated emission intensity at 300 °C kept 96% of room temperature. • High internal quantum efficiency over 90% under 300–410 nm excitation. • A promising phosphor for near UV pumped white LEDs. -- Abstract: Single phase powders of green emitting Ba₂LiSi_7-xAl_xN_12-xO_x:Eu²⁺ phosphor were prepared by controlling the starting compositions, annealing conditions and reaction vessels. The emission peak of Ba₂LiSi_7-xAl_xN_12-xO_x:Eu²⁺ phosphor shifted from 502 nm to 515 nm depending on the Eu concentration. The intensity was highest with an Eu concentration of 3 at%. The phosphor showed a small thermal quenching of luminescence intensity and the integrated intensities at 200 °C and 300 °C were 100% and 96%, respectively, of the intensity observed at room temperature. The phosphor washed by hydrochloric acid solution showed a high internal quantum efficiency (QE) value of 93% with 400 nm excitation.