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

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.