Influences of phase composition on Sr3SiO5:Eu2+ luminous performance

α′-Sr2SiO4:Eu2+ phase always coexists with the Sr3SiO5:Eu2+ phase when it is synthesized by a high-temperature solid-state method. This may affect the luminescent properties of the Sr3SiO5:Eu2+ phosphors. We investigated the decomposition reaction of Sr3SiO5 during the cooling process with the quenching method. The results indicated that Sr3SiO5 was a stable compound above 1250 °C. The Sr3SiO5 phase decomposed into α′-Sr2SiO4 and SrO below 1250 °C. The α′-Sr2SiO4:Eu2+ phase would coexist with the Sr3SiO5:Eu2+ phase because of the decomposition reaction of Sr3SiO5, making the luminescent wavelength of coexistence sample move to the short-wavelength compared with the luminescent wavelength of Sr3SiO5:Eu2+. Pure phase Sr3SiO5:Eu2+ could be obtained by the rapid cooling method to suppress Sr3SiO5 decomposition. When the cooling rate was 20 °C/min, nearly pure phase Sr3SiO5:Eu2+ could be produced.