Luminescence properties and energy transfer of Ca2Mg0.5AlSi1.5O7:Ce3 +, Eu2 + phosphors for UV-excited white LEDs

Ce3 + and/or Eu2 + activated Ca2Mg0.5AlSi1.5O7 phosphors have been synthesized by high temperature solid state reaction. The luminescence of Ca2Mg0.5AlSi1.5O7:Ce3 +, Eu2 + is studied as potential ultraviolet light-emitting diodes (UV-LEDs). There are two emissions peaked at 409 and 525 nm which come from d–f transitions of Ce3 + and Eu2 + ions. The energy transfer from the Ce3 + to Eu2 + has been discussed and it is demonstrated to be a resonant type via a dipole–dipole mechanism. The critical distance of Ce3 + to Eu2 + in Ca2Mg0.5AlSi1.5O7 has been calculated to be 26.71 Å by spectral overlap method. Furthermore, the Ca2Mg0.5AlSi1.5O7:Ce3 +, Eu2 + phosphors can emit a tunable blue-to-green light under the excitation of 350 nm by appropriately tuning the relative proportion of Ce3 +/Eu2 +, indicating that the phosphors Ca2Mg0.5AlSi1.5O7:Ce3 +, Eu2 + are promising blue-to-green emitting phosphors for application in pc-white LEDs.