Effects of Lanthanum substitution on the luminescence properties and energy transfer mechanism of Gd9.33(SiO4)6O2:Ce polycrystalline

Abstract (Gd,La) 9.33 (SiO 4 ) 6 O 2 :Ce polycrystalline powder with different proportion of Gd/La and Ce concentration was prepared by sol-gel technique, the crystal structure was confirmed by XRD, the luminescence properties were discussed under UV excitation. The energy transfer of Gd-Gd and Gd-Ce have been systematically investigated using luminescence spectra and there are three different types transfer mechanism for different Ce 3+ and La 3+ concentrations. The nonradiative energy transfer mechanism can switch from a short-range exchange mechanism to a longer-range dipole–dipole mechanism through energy migration between donors in heavily La substituted samples. The luminescence thermo-stability and activation energy were also measured and calculated. The luminescence properties and thermo-stability of Gd 9.33 (SiO 4 ) 6 O 2 :Ce polycrystalline were improved, because of La 3+ substitution which lead to the change of the energy transfer mechanism from Gd 3+ to Ce 3+