Tb3+→Ce3+ energy transfer in Y3-x-yTbyGdxAl5O12 (x=0.65, y=0.575) doped with Ce3+

Abstract Photoluminescence and luminescence excitation spectra of Y 2.3 - x Tb x Ce 0.05 Gd 0.65 Al 5 O 12 ( x = 0.575 ) have been measured at room temperature. Depending on the excitation wavelength the broad band emission related to interconfigurational transitions in Ce 3 + ions, or the sharp lines luminescence related to D 4 5 → F 6 7 , D 4 5 → F 5 7 , D 4 5 → F 4 7 and D 4 5 → F 3 7 , transitions in Tb 3 + ions have been observed. It has been found that efficiency of Tb 3 + → Ce 3 + energy transfer depends on the excitation energy, specifically it is less effective when Tb 3 + is excited to the lowest state of the excited 5 d 1 4 f 7 electronic configuration. This effect has been tentatively attributed to the nonradiative de-excitation of Tb 3 + ion to the metastable 5 D 4 state. Configurational model has been developed, which explains the peculiarities of relaxation in the excited states of Tb 3 + and Ce 3 + , and Tb 3 + → Ce 3 + energy transfer.