Hydrothermal synthesis, energy transfer and luminescent properties of β-NaLuF4:Ce3+/Gd3+/Sm3+ microcrystals

In this study, Ce3+, Gd3+ and Sm3+ co-doped β-NaLuF4 micro-prisms with prominently uniform shape and size have been successfully prepared by a facile and efficient hydrothermal strategy. By modifying the dopant concentration of migrator (Ce3+) and activator (Sm3+), the luminescent properties of β-NaLuF4:Ce3+/Gd3+/Sm3+ samples are systematically studied and the corresponding energy transfer (ET) mechanism can be discussed in detail. Impressively, upon the excitation into the electric-dipole-allowed 4f→5d transition of Ce3+ ions at 250 nm, the efficient ET from Ce3+ ions (sensitizer) to Sm3+ ions (activator) can be realized through the Ce3+→(Gd3+)n→Sm3+ energy migration process, in which the Gd3+ (migrator) acts as a bridge center to yield intense orange emission from Sm3+ ions. The above results not only enrich the knowledge of the synthetic chemistry and optical spectroscopy of luminescent materials, but also endow such materials with potential applications in a diversity of fields.