Tunable color and energy transfer in single-phase white-emitting Ca20Al26Mg3Si3O68:Ce3+,Dy3+ phosphors for UV white light-emitting diodes

• The Ca20Al26Mg3Si3O68:Ce3+,Dy3+ are novel luminescent materials that have not been reported before.
• The crystal structure of Ca20Al26Mg3Si3O68 and energy transfer from Ce3+ to Dy3+ were investigated.
• The emission color of Ca20Al26Mg3Si3O68:Ce3+,Dy3+ can be adjusted from blue to white.
• The phosphors have great application value in WLEDs as a kind of blue-to-white emitting phosphors.

Ce3+ and/or Dy3+ activated Ca20Al26Mg3Si3O68 phosphors were synthesized by high temperature solid state reaction and their luminescent properties were studied. There are two emissions peaking at 407 and 577 nm in the emission spectra of Ca20Al26Mg3Si3O68:Ce3+, Dy3+, which are due to the transitions of Ce3+ and Dy3+ ions, respectively. More importantly, the effective energy transfer from Ce3+ to Dy3+ ions has been confirmed and investigated by emission/excitation spectra and luminescent decay behaviors. Furthermore, the energy level scheme and mechanism of energy transfer were investigated and it was demonstrated to be resonant type via dipole–dipole reaction. Under the excitation of 345 nm, the emitting color can change from blue to white by adjusting the relative doping concentration of Ce3+ and Dy3+ ions, indicating that the phosphors Ca20Al26Mg3Si3O68:Ce3+, Dy3+ are promising single-phase white-emitting phosphors for application in pc-white LEDs.

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