Luminescence properties of nitride red phosphor for LED

Eu2+-doped ternary nitride phosphor, Sr2Si5N8:Eu2+, was synthesized using the high temperature solid-state method. The X-ray diffraction (XRD) pattern showed that Sr2Si5N8 single phase was obtained. The lattice parameters shrank because the radius of Eu2+ was smaller than that of Sr2+. The emission spectra showed a broad emission band. With an increase in Eu2+ concentration, the emission peak position was redshifted. The excitation spectra showed two excitation bands originating from the host and the 4f7→4f65d1 transition of Eu2+ ions. Compared with the luminescent characteristic of Sr2Si5N8:Eu2+ and CaS:Eu2+ phosphors, at different temperatures, it was noted that the intensity of the two phosphors reduced gradually with an increase in temperature. The intensity of Sr2Si5N8:Eu2+ phosphor was stronger than that of CaS:Eu2+, which indicated that the luminescent characteristic of the former was better than that of the latter.