On the Factors Determining the Titanate Luminescence in Solids

The luminescence spectra of Y2TiO5 and Y2Ti2O7, NaSn2−xTix(PO4)3 and Y3Ga5O12:Ca,Ti are reported. The titanate host lattices are also doped with Eu3+. The data are discussed in terms of existing models. It is shown that a relation between quenching temperature and excitation maximum of the titanate emission holds and has a fundamental background. However, this is only the case for structurally and energetically isolated titanate groups. Factors like delocalisation and photo-ionisation influence the relation drastically as is shown by examples.