Bi3+-doped Sr3Al2O6: An unusual color-tunable phosphor for solid state lighting

A Sr3−xAl2O6:xBi3+ phosphor crystallized in space group image was prepared by high-temperature solid-state reaction. Two emission bands (λem=440 nm and 400 nm) and two excitation bands (λex=330 nm and 295 nm) were observed, which can be attributed to Bi3+ in distinct crystallographic sites. The optimal intensity of 400 nm emission band was observed for the phosphor doped with 1 at% Bi3+ (x=0.01), while that of 440 nm emission band was found in the phosphor with 2 at% Bi3+ (x=0.02). The emission color varies from the greenish blue to blue and even violet blue as the excitation wavelength increases from 275 to 335 nm. The Sr3−xAl2O6:xBi3+ is a potential blue phosphor for ultraviolet light-emitting diodes.