Broad-Band Excited and Tunable Luminescence of CaTbAl3O7:RE3+ (RE3+ = Ce3+ and/or Eu3+) Nanocrystalline Phosphors for Near-UV WLEDs.

Here, we demonstrate a novel donor-intermediate-receptor energy transfer model through a Ce3+ → Tb3+ → Eu3+ scheme in a CaTbAl3O7:Ce3+,Eu3+ nanocrystalline phosphor. A new type of CaTbAl3O7 and CaTbAl3O7:RE3+ (RE3+ = Ce3+ and/or Eu3+) nanocrystalline phosphors were prepared by a simple sol-gel method. There exist efficient energy transfers of Ce3+ → Tb3+, Tb3+ → Eu3+, and Ce3+ → Tb3+ → Eu3+ in CaTbAl3O7:RE 3+ (RE 3+ = Ce3+ and/or Eu3+) nanocrystalline phosphors. With near-UV or UV light excitation, the as-prepared CaTbAl3O7:RE 3+ (RE 3+ = Ce3+ and/or Eu3+) 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 Ce3+ to Eu3+ ions in the CaTbAl3O7 matrix. The luminescence mechanism with respect to the CaTbAl3O7:RE3+ (RE3+ = Ce3+ and/or Eu3+) nanocrystalline phosphors has been tentatively proposed. Due to their excellent luminescence properties, the as-prepared CaTbAl3O7, CaTbAl3O7:Ce3+, CaTbAl3O7:Eu3+, and CaTbAl3O7:Ce3+,Eu3+ nanocrystalline phosphors exhibit bright prospects in NUV-LEDs and other photoelectric field.