Tunable emission from green to red in the GdSr2AlO5:Tb3+,Eu3+ phosphor via efficient energy transfer

Herein, a series of GdSr2AlO5:Tb3+,Eu3+ phosphors were successfully synthesized through a high temperature solid-state reaction, and their crystal structures as well as photoluminescence properties were investigated in detail. Compared to the intense emission of D-5(0) -> F-7(1) or D-5(0) -> F-7(2) transition of Eu3+, another strong emission corresponding to D-5(0) -> F-7(4) was observed. Concentration quenching is not obvious in Tb3+ or Eu3+-doped GdSr2AlO5 because structure isolation and energy transfer (ET) of Gd3+ -> Eu3+ and Gd3+ -> Tb3+ were found. Moreover, the energy transfer process from Tb3+ to Eu3+ was verified by the overlap of luminescence spectra and the variation of lifetime. Energy transfer mechanism was determined to be a dipole-dipole interaction, and ET efficiency as well as quantum efficiency were also obtained. Moreover, the emission color of GdSr2AlO5:Tb3+, Eu3+ can be tuned from green to red by altering the ratio of Tb3+/Eu3+. These results indicate that the GdSr2AlO5:Tb3+,Eu3+ phosphor is a promising single-component white light-emitting phosphor.