Novel energy transfer mechanism in single-phased color-tunable Sr2CeO4:Eu3+ phosphors for WLEDs

• The synthesized Sr2CeO4:Eu3+ phosphors were firstly probed by the Rietveld refinement.
• The luminescence properties of Sr2CeO4:Eu3+ were systematically investigated.
• The energy transfer from the Ce4+–O2− CTS to Eu3+ was discussed in detail based on the Inokuti–Hirayama theory.

A series of color-tunable Sr2CeO4:Eu3+ phosphors have been successfully synthesized. The Rietveld refinement was firstly used to probe the phase purity and the structure of Sr2CeO4:Eu3+. The photoluminescence excitation spectra exhibit that the phosphors show a broad excitation band from 200 to 400 nm, which concurs well with the commercial near-UV LED. The photoluminescence spectra vary with the dopant content due to the energy transfer and the tunable blue-red color can be simply achieved by altering the doped Eu3+ ions concentrations. On the basis of the Inokuti–Hirayama theory, we obtained that the dipole-dipole interaction type takes charge for the energy transfer from the Ce4+–O2− charge-transfer state transition to Eu3+ ions and the schematic was plotted to illuminate the possible energy transfer process. The experimental results indicate that Sr2CeO4:Eu3+ phosphors may be potentially used as promising single-phased phosphors for near-UV white light-emitting diodes applications.