Preparation of Eu-activated strontium orthosilicate (Sr1.95SiO4:Eu0.05) phosphor by a sol–gel method and its luminescent properties

Eu2+-activated Sr2SiO4 phosphor was successfully synthesized by a sol–gel method using sodium silicate and SrO as the starting materials. The wavelength of the emission peak and the emission intensity of the phosphor powders were influenced by the pre-treating temperature. The maximum emission intensity of the phosphor was found as pre-treated at 1200 °C in air and then heated at 1300 °C in the reducing atmosphere (10% H2 + 90% He). As the pre-treating temperature was <1200 °C, the composition of the phosphor powder was not uniform, which leads to decrease of the emission intensity, whereas >1200 °C, the decrease of the emission intensity may be caused from the reversible phase transformation of Sr3SiO5 → Sr2SiO4 at 1300 °C, which also shows the red-shift behavior.