title: Luminescence and energy transfer characteristics of Ce3+- and Tb3+-codoped nanoporous 12CaO 7Al2O3 phosphors.
abstract: The novel green-emitting phosphors of 12CaO 7Al2O3:Ce3+ , Tb3+ (C12A7:Ce3+, Tb3+) were synthesized by a solid-state reaction. Upon the excitation of Ce3+ at 350 nm, the C12A7:Ce3+, Tb3+ phosphor shows intense green emissions located at 543 nm assigning to 5D4-7F5 transitions of Tb3+ ions, and weak blue emissions centered at 434 nm due to the transitions of Ce3+ 5d-4f. The photoluminescence (PL) intensity of Ce3+ decrease with increasing Tb3+ concentration, indicating the effective energy transfer (ET) occurred from Ce3+ to Tb3+ in C12A7:Ce3+, Tb3+. The ET efficiency between Ce3+ and Tb3+ in the optimum composition reaches to 99%. Based on Dexter's ET theory, we have demonstrated that the efficient ET is a resonant type via dipole-dipole mechanism with an energy transfer critical distance of 4.02 A. Our results suggested that C12A7:Ce3+, Tb3+ phosphor would be a promising green-emitting phosphor for UV-converting white light-emitting diodes.
authors.affiliation: Center for Advanced Optoelectronic Functional Materials Research, Northeast Normal University, Changchun 130024, People's Republic of China.
authors.forename: X L
authors.initials: XL
authors.lastname: Liu
authors.forename: Y X
authors.initials: YX
authors.lastname: Liu
authors.forename: D T
authors.initials: DT
authors.lastname: Yan
authors.forename: H C
authors.initials: HC
authors.lastname: Zhu
authors.forename: C G
authors.initials: CG
authors.lastname: Liu
authors.forename: C S
authors.initials: CS
authors.lastname: Xu