Enhanced red fluorescence in Sr2Si1−xGexO4:Eu3+ phosphors by the substitution of Si by Ge for white light emitting diodes

Eu3+-doped Sr2Si1−xGexO4 (x=0–1) phosphors have been prepared by the high temperature solid-state reaction method. The luminescent properties of these phosphors were investigated. Red fluorescence of Eu3+ is enhanced gradually in the samples with increasing substitution of Si by Ge upon the excitation of 393 nm light. The intensity is increased by 50% with full substitution of Si by Ge. These results are originated from the structural changes and the phonon energy reduction in the samples due to the substitution of Si by Ge. The CIE chromaticity coordinates of the phosphors vary slightly around (0.62, 0.37) and all are in the red color region. The results indicate that these phosphors could be promising red phosphors for white light emitting diodes.

► We investigated luminescent properties of Sr2Si1−xGexO4:Eu3+ (x=0–1) phosphors. ► Red fluorescence was gradually enhanced with increasing Ge substitution of Si. ► The intensity was increased by 50% with full substitution of Si by Ge. ► Enhanced red fluorescence is due to structural changes and lower phonon energy. ► The phosphors could be promising red phosphors for white light emitting diodes.