Energy transfer mechanisms in CaAl12O19:Ce0.06 3+,Eux 2+ phosphors

Abstract

CaAl12O19:Ce0.06 3+,Eux 2+ phosphors were synthesized through a combustion process, and their optical properties were investigated using cathodoluminescence (CL) measurements. The results for the CL spectra showed that different energy transfer mechanisms exist in CaAl12O19:Ce0.06 3+,Eux 2+ and are dependent on the Eux 2+ acceptor concentration. As the Eux 2+ acceptor concentration increased, the lifetime of the Ce3+ donor decreased, while that of the donor related to the diffusion increased. The dominant energy transfer at low concentrations of the Eux 2+ acceptor in CaAl12O19:Ce0.06 3+,Eux 2+ was attributed to the electric dipole-dipole interaction between the Ce3+ donors and the Eu2+ acceptors, resulting from the diffusion limited energy migration. While a similar energy transfer mechanism at the high concentrations of the Eu2+ acceptor in CaAl12O19:Ce0.06 3+,Eux 2+ dominated in the transient state part, a different energy transfer mechanism appeared in the steady state part of the decay process.