Luminescence and energy transfer in yttrium-niobate (YNbO4)

The luminescence properties of yttrium niobate are reported. Two emission bands are observed, one in the blue and the other in the yellow spectral region. Decay measurements on the blue emission, which is the intrinsic niobate luminescence, provide evidence that this luminescence cannot be described with a tetrahedral niobate group. The yellow emission is ascribed to a niobate group lacking an oxygen ion. Experiments on energy transfer reveal that the main process involved in the thermal quenching of the luminescence of yttrium niobate is not energy transfer between niobate groups, but thermal quenching within the excited niobate group. (author)