Processes of the excitation energy migration and transfer in Ce3+-doped alkali gadolinium phosphates studied with time-resolved photoluminescence spectroscopy technique

►We investigate the Gd3+-Ce3+ energy transfer in alkali gadolinium phosphates. ► Thermal population of Gd3+6P5/2 level improves migration along the Gd sub-lattice. ► Increasing overlap of Gd3+ and Ce3+ states enhances the Gd3+-Ce3+ energy transfer. ► In LiGdP4O12:Ce and NaGdP4O12:Ce an efficient Ce3+-Gd3+ transfer occurs at 4-300 K. ► An effective reverse Gd3+-Ce3+ energy transfer becomes possible at T>150 K.