Luminescent properties of green- or red-emitting Eu2+-doped Sr3Al2O6 for LED

Eu2+-doped Sr3Al2O6 (Sr3−xEuxAl2O6) was synthesized by a solid-state reaction under either H2 and N2 atmosphere or CO atmosphere. When H2 was used as the reducing agent, the phosphor exhibited green emission under near UV excitation, while CO was used as the reducing agent, the phosphor mainly showed red emission under blue light excitation. Both emissions belong to the d–f transition of Eu2+ ion. The relationship between the emission wavelengths and the occupation of Eu2+ at different crystallographic sites was studied. The preferential substitution of Eu2+ into different Sr2+ cites at different reaction periods and the substitution rates under different atmospheres were discussed. Finally, green-emitting and red-emitting LEDs were fabricated by coating the phosphor onto near UV- or blue-emitting InGaN chips.