Luminescent properties of Eu3+ and Tb3+ activated Zn3Ta2O8

This paper reports a systematic investigation on photoluminescent (PL) properties of Eu3+ and Tb3+-activated Zn3Ta2O8. The excitation spectrum of Zn3Ta2O8:Eu3+ consists of the strong CTS absorption and week f-f transitions of Eu3+, while the excitation spectrum of Zn3Ta2O8:Tb3+ is composed of the strong d-f transition and weak f-f transitions of Tb3+. The charge transfer state (CTS) band of Eu3+ and the d-f peak of Tb3+ slightly shift to lower energy with increase of dopant contents. Zn3Ta2O8:Eu3+ exhibits red emission peaks around 610-620 nm, which is related to the transitions of D-5(0)-->F-7(2). The luminescence of Zn3Ta2O8:Tb3+ is dominated by green emission peaks at 546 nm, which can be attributed to the transition of (D4-->F5)-D-5-F-7. For Eu3+-Tb3+ codoped Zn3Ta2O8, energy transfer process takes place and the resonant mechanism is proposed as the transfer mechanism which can be described as: D-5(4)(Tb3+)+F-7(0)(Eu3+)-->F-7(5)(Tb3+)+D-5(1)(Eu3+). PL spectra and lifetime measurements support this mechanism. Due to the energy transfer, PL intensity of Eu3+ emission increased about 40%. (C) 2003 The Electrochemical Society.