Effects of doping concentration and co-doping with cerium on the luminescence properties of Gd3Ga5O12:Cr3+ for thermometry applications

The accuracy of surface temperature measurements using thermographic phosphors relies on an extensive knowledge of the temperature-dependent properties of the phosphor. This paper addresses the effects of doping concentration and co-doping with cerium on the luminescence properties of the Gd3Ga5O12:Cr3+ phosphor. High-crystallinity Gd3Ga5O12:Cr3+,Ce3+ powder samples (GGG:Cr,Ce) with different Cr3+ and Ce3+ concentrations were synthesized, and their luminescence spectra as well as their decay lifetime properties were characterized after UV laser excitation. Results revealed that the concentration quenching decreases the luminescence lifetime at concentrations above 0.5 mol% Cr3+ while the emission spectrum remains independent of the Cr3+ concentration. Co-doping with small amounts of Ce3+ improves the temperature-dependent luminescence characteristics by reducing the afterglow and producing fairly mono-exponential luminescence decays without changing the lifetime.