New Oxide Phosphors for FEDs; Ruddlesden-Popper Phases Synthesized with III-Group Elements

摘要

A red-emitting phosphor, SrTiO_3:Pr~(3+), for low-voltage type FEDs was developed by Futaba Corporation in 1996. Addition of Al or Ga is essential to the preparation of this phosphor, since it improves the luminescence efficiency dramatically. For this impurity effect, Futaba Corporation proposed charge compensation mechanism, which was supported by a recent observation of emission lines due to Al~(3+)-Pr~(3+) pairs. In addition it was found that Al also works as a scavenger of planar defects, presumably SrO thin layers interleaved in the SrTiO_3 lattice, by forming strontium aluminates. The latter mechanism suggests a possibility that a similar impurity effect can be found in materials with the crystal structures including alkaline-earth oxide layers; Ruddlesden-Popper Phases.