Multiple Energy Transfer in Luminescence-Tunable Single-Phased Phosphor NaGdTiO(4): Tm(3+), Dy(3+), Sm(3+)

Advances in solid-state white-light-emitting diodes (WLEDs) necessitate the urgent development of highly efficient single-phase phosphors with tunable photoluminescence properties. Herein, the Tm(3+), Dy(3+), and Sm(3+) ions are incorporated into the orthorhombic NaGdTiO(4) (NGT) phosphors, resulting in phosphors that fulfill the aforementioned requirement. The emission spectrum of Tm(3+) ions overlaps well with the adsorption spectra of both Dy(3+) and Sm(3+) ions. Under the excitation at 358 nm, the single-phase NaGdTiO(4): Tm(3+), Dy(3+), Sm(3+) phosphor exhibits tunable emission peaks in the blue, yellow, and red regions simultaneously, resulting in an intense white-light emission. The coexisting energy transfer behaviors from Tm(3+) to Dy(3+) and Sm(3+) ions and the energy transfer from Dy(3+) to Sm(3+) ions are demonstrated to be responsible for this phenomenon. The phosphors with multiple energy transfers enable the development of single-phase white-light-emitting phosphors for phosphor-converted WLEDs.