Insights into Ba4Si6O16 structure and photoluminescence tuning of Ba4Si6O16:Ce3+,Eu2+ phosphors

Abstract

The versatile polymorphism and chemical compositions of barium silicates have been studied for a long time and their crystal structures have been established. Herein, we focused on the understanding of the crystal structure of the Ba₄Si₆O₁₆ phase and the structural correlation of Ba₄Si₆O₁₆ and Ba₂Si₃O₈; moreover, the luminescence properties of Ce³⁺,Eu²⁺-co-activated Ba₄Si₆O₁₆ phosphors have been discussed. Ba₄Si₆O₁₆:Ce³⁺,Eu²⁺ phosphors show tunable blue-green emission upon excitation with 365 nm ultraviolet (UV) light. The blue emission originates from Ce³⁺, whereas the bluish-green emission is ascribed to Eu²⁺, and variation in the emission peak wavelength from 442 to 497 nm can be achieved by properly tuning the Ce³⁺/Eu²⁺ ratio. Energy transfer from Ce³⁺ to Eu²⁺ in the Ba₄Si₆O₁₆ host has been validated by the variation of emission spectra as well as the variation of Ce³⁺ decay lifetimes with increasing Eu²⁺ concentration, and the energy transfer mechanism is demonstrated to be a resonant type via a dipole–dipole process. The results suggest that Ba₄Si₆O₁₆:Ce³⁺,Eu²⁺ phosphors are potential candidates as a blue-green component for UV-excited white light-emitting diodes.