Correlation between structure variation and luminescence red shift in YAG:Ce

Red shift of Ce3+ luminescence in Y3Al5O12 (YAG) co-doped with Gd3+ is investigated with X-ray diffraction (XRD) based structural analysis and crystal-field modeling of electronic energy levels. It shows a linear relationship between the lattice expansion induced by substituting Gd3+ for Y3+ and the red shift in the Ce3+ luminescence. A crystal-field analysis of the Ce3+ 5d energy levels is conducted to establish the correlation between the YAG lattice expansion and the Ce3+ energy level shifts.