Enhanced Luminescence of NaY0.6–xCe0.1Gd0.3EuxF4 Nanorods by Energy Transfers between Ce3+, Gd3+, and Eu3+

In this study, hexagonal-phase NaY0.6–xCe0.1Gd0.3EuxF4 nanorods were synthesized via a mild solvothermal method. By modifying the Eu3+ dopant concentration, the crystal phase, morphology, and luminescent properties were well controlled. A broad excitation band centered at around 260 nm corresponding to the 2F5/2 → 4f-5d transition of Ce3+ was detected in the hosts containing Gd3+ ions by monitoring the Eu3+ emissions, indicating that an efficient Ce3+ → Eu3+ energy transfer occurred via the Gd3+ sublattice. Luminescence decay behaviors of the NaY0.6–xCe0.1Gd0.3EuxF4 nanorods were studied, and the energy transfer mechanism was discussed. An obvious rising edge on the luminescence decay curve of Eu3+ ions in the NaY0.6–xCe0.1Gd0.3EuxF4 nanorods was observed. The rising time is proposed to describe the energy migration time from Ce3+ to Eu3+ via the Gd3+ sublattice.