Red luminescence induced by intervalence charge transfer in Pr3+-doped compounds

The 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 3P0 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 IVCTS 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.