title: A novel tunable blue-green-emitting CaGdGaAl2O7:Ce(3+),Tb(3+) phosphor via energy transfer for UV-excited white LEDs.
abstract: CaGdGaAl2O7 and CaGdGaAl2O7:Ce(3+),Tb(3+) have been synthesized by a traditional solid state reaction for the first time. The Rietveld refinement confirmed that CaGdGaAl2O7 has a tetragonal crystal system with the space group P4[combining macron]21m. The photoluminescence properties show that the obtained phosphors can be efficiently excited in the range from 330 to 400 nm, which matches perfectly with commercial UV LED chips. A tunable blue-green emitting CaGdGaAl2O7:Ce(3+),Tb(3+) phosphor has been obtained, by codoping Ce(3+) and Tb(3+) ions into the host and varying their relative ratios, and may be a good candidate for blue-green components in UV white LEDs. The luminescence properties and lifetimes reveal an efficient energy transfer from the Ce(3+) to Tb(3+) ions. The energy transfer is demonstrated to be a dipole-quadrupole mechanism, and the critical distance for Ce(3+) to Tb(3+) calculated by the concentration quenching is 12.25 Å.
authors.affiliation: Jiangsu Bree Optronics Co. Ltd, Nanjing 211103, China. hejinhua_2001@aliyun.com.
authors.forename: Chao
authors.initials: C
authors.lastname: Liang
authors.forename: Hongpeng
authors.initials: H
authors.lastname: You
authors.forename: Yibing
authors.initials: Y
authors.lastname: Fu
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Teng
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.forename: Jinhua
authors.initials: J
authors.lastname: He