Tunable Luminescence of CeAl11O18 Based Phosphors by Replacement of (AlO)+ by (SiN)+ and Co-Doping with Eu

A series of Si-N or Eu-Li doped CeAl11O18 and CeAl12O18N phosphors are prepared by solid-state reaction. Their structure and luminescence are researched carefully. Si-N doping with the concentration less than 8% can be successfully dissolved into CeAl11O18 crystal lattice and doesn't change the matrix structure, only resulting in crystal lattice shrinkage due to the shorter bond length for Si-N bond versus Al-O bond. It is observed that blue emission gradually decreases and UV emission becomes stronger due to the gradual disappearance of OMe ions with the increase of Si-N doping. Compared with the traditional UV emitting phosphor CeMgAl11O19, Si-N doped CeAl11O18 shows better thermal stability. The crystal structure and lattice parameters of Eu-Li codoped CeAl11O18 remain unchanged due to the large tolerance of rare-earth sites. On account of the energy transfer from UV emission of Ce3+ to Eu2+, a single overlapping blue emission with high intensity is obtained in Eu-Li codoped CeAl11O18 phosphor.