Broad-Band Excited and Tunable Luminescence of CaTbAlO:RE (RE = Ce and/or Eu) Nanocrystalline Phosphors for Near-UV WLEDs.

Here, we demonstrate a novel donor-intermediate-receptor energy transfer model through a Ce → Tb → Eu scheme in a CaTbAlO:Ce,Eu nanocrystalline phosphor. A new type of CaTbAlO and CaTbAlO:RE (RE = Ce and/or Eu) nanocrystalline phosphors were prepared by a simple sol-gel method. There exist efficient energy transfers of Ce → Tb, Tb → Eu, and Ce → Tb → Eu in CaTbAlO:RE (RE = Ce and/or Eu) nanocrystalline phosphors. With near-UV or UV light excitation, the as-prepared CaTbAlO:RE (RE = Ce and/or Eu) nanocrystalline phosphors' luminous color can be regulated from green to green-yellow, yellow, orange, and orange-red by adjusting the doping concentration, categories, and different proportions of codoping Ce to Eu ions in the CaTbAlO matrix. The luminescence mechanism with respect to the CaTbAlO:RE (RE = Ce and/or Eu) nanocrystalline phosphors has been tentatively proposed. Due to their excellent luminescence properties, the as-prepared CaTbAlO, CaTbAlO:Ce, CaTbAlO:Eu, and CaTbAlO:Ce,Eu nanocrystalline phosphors exhibit bright prospects in NUV-LEDs and other photoelectric field.