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Metal-to-metal charge transfer involving Pr3+ or Tb3+ ions in transition metal oxides and its consequences on the luminescence behaviors
No full textIntervalence charge transfer in Pr3+- and Tb3+-doped double tungstate crystals KRE(WO4)(2) (RE = Y, Gd, Yb, Lu)
No full textFirst experimental evidences of intervalence charge transfer (IVCT) transitions in PO3+- and Tb3+-doped double tungstate crystals KRE(WO4)(2) (RE = Y, Gd, Yb, Lu) are reported. The IVCT bands are located nearly at the same energies for Pr3+ and Tb3+ in a given crystal and these energies are consistent with an empirical model recently developed for Pr3+ ions in titanates, vanadates, niobates and tantalates. These data made it possible to locate the 4f(n) states of trivalent lanthanides in KREW crystals by applying the "double seat" empirical model proposed by Dorenbo
Red luminescence induced by intervalence charge transfer in Pr3+-doped compounds
No full textThe excited state dynamics of the Pr3+ in oxide lattices is revisited in the light of the 'virtual recharge' model. The connection between the quenching of the blue-green emission from the P-3(0) level and the formation of a Pr3+ to metal intervalence charge-transfer state (IVCTS) is discussed on the basis of new experimental evidences. Updated information is presented, concerning the energy position of the lVCTS in various materials and its relation with the host properties. Finally, the limits of the proposed model are outlined and the perspectives for future work are pointed out
Luminescence of Pr3+ in titanates and vanadates : towards a criterion to predict 3P0 emission quenching
No full text
Excited state dynamycs of Pr3+ in YVO4 crystals
No full textThe quenching mechanism of the emission from the 3P0 level of Pr3+ doped into YVO4 has been
investigated by means of optical spectroscopy techniques. Continuous wave and time-resolved
emission and excitation measurements have been carried out as a function of the temperature and of
the dopant concentration in order to obtain information on the energy-transfer processes involved in
the host sensitization of the red luminescence and in the depopulation of the emitting states. The
experiments have also been extended to LaVO4:Pr3+ and YPO4:Pr3+, i.e., two crystals for which the
3P0 emission is stronger than for YVO4:Pr3+, with the aim of studying the relationship between of
the host properties and the optical behavior of the Pr3+ ion
Luminescence properties of Pr3+ in titanates and vanadates: Towards a criterion to predict 3P0 emission quenching
No full textLuminescence spectra of Pr3+ in 15 titanate and vanadate lattices have been measured under LW excitation. They are characterized by a dominant red luminescence assigned to transitions from the D-1(2) level to the ground state. The quenching of the otherwise prominent blue luminescence from P-3(0) state is ascribed to a relaxation pathway involving a low-lying Pr3+-Mn+ (Mn+ = Ti4+ or V5+) intervalence charge transfer (IVCT) state. Complete quenching of the P-3(0) emission takes place when the IVCT bands are located in the 2650028 000 cm(-1) range and the shortest Pr3+-Mn+ distances are in the 3.15-3.30 angstrom rang
Luminescent properties of Pr3+ in titanates and vanadate: towards a criterion to predict 3P0 emission quenching
No full textExcited state dynamics of Pr3+ in YVO4 crystals
No full textThe quenching mechanism of the emission from the P-3(0) level of Pr3+ doped into YVO4 has been investigated by means of optical spectroscopy techniques. Continuous wave and time-resolved emission and excitation measurements have been carried out as a function of the temperature and of the dopant concentration in order to obtain information on the energy-transfer processes involved in the host sensitization of the red luminescence and in the depopulation of the emitting states. The experiments have also been extended to LaVO4:Pr3+ and YPO4:Pr3+, i.e., two crystals for which the P-3(0) emission is stronger than for YVO4:Pr3+, with the aim of studying the relationship between of the host properties and the optical behavior of the Pr3+ ion. (C) 2004 American Institute of Physics
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