Visible light emission under UV and IR excitation of rare earth doped ZrO2 nanophosphor

Strong visible emission under UV (320 nm) and IR (967 nm) excitation on ZrO2:Sm 3+ and ZrO2:Er 3+ nanophosphors were obtained and the concentration effect on the luminescence and crystalline structure is reported. Experimental results shows that phase composition depend on the ion concentration. The visible emission obtained under UV excitation is produced by the transitions G5/2 ! H5/2,7/2,9/2 of Sm through a non-radiative energy transfer process from the host to the active ion. Energy transfer and quenching effect due to ion concentration was confirmed by measuring the fluorescence decay time. Green (545 nm) and red (680 nm) emissions bands were observed under IR excitation troughs an upconversion process. It was proved that visible emission for both nanophosphor could be tuned by controlling the ion concentration. The nature of this behavior is discussed taking into account the phase composition for ZrO2:Sm 3+ and two photon absorption and cross-relaxation process was considered for ZrO2:Er 3+ nanophosphor. 2004 Elsevier B.V. All rights reserved.