Tunable Blue-Green-Emitting Na4CaSi3O9:Ce3+,Li+,Tb3+ Phosphor with Energy Transfer for Near-UV White LEDs

Abstract Phosphor-converted white light emitting diodes (w-LEDs), with high luminous efficiency, low energy consumption, extended lifetime, and eco-friendly nature, have revolutionized various industries. Among them, an alkaline earth silicate-based phosphor host, Na4CaSi3O9, shows good crystal structure stability and flexible properties for diverse application. Here, Ce3+/Li+ singly doped and Ce3+/Li+/Tb3+ co-doped Na4CaSi3O9 phosphors are fabricated by the standard solid-state reaction approach. The Ce3+/Li+-activated phosphors show strong absorption within 200–400 nm and exhibit a blue emission centered at 423 nm. The quenching concentration of Ce3+ appears at x = 0.05 and can be attributed to the dipole–quadrupole interaction. When Tb3+ ions are co-doped, the Na4CaSi3O9:Ce3+,Li+,Tb3+ phosphor emission can be adjusted from blue to green under the irradiation of 365 nm through the dipole–dipole interaction induced energy transfer from Ce3+ to Tb3+ ions with a maximum value of 28.32%. This study highlights the Na4CaSi3O9:Ce3+,Li+,Tb3+ phosphors as a new and efficient material for w-LED applications.