Photoluminescence characteristics of new stannate pyrochlore based red phosphors: CaLaSnNbO_7: Eu~(3+)

摘要

New stannate pyrochlore based red emitting phosphor materials: CaLa_(1-X)SnNbO_7: xEu~9~(3+) were prepared by the conventional solid state route and characterized by Powder X-ray diffractometer, scanning electron microscope and fluorescence measurements. Optimization studies by way of varying the calcination temperatures show that CaLaSnNbO_7: Eu~(3+) prepared at 1,400 ℃ displayed the maximum luminescence characteristics. The dominant emission peak of CaLaSnNbO_7: xEu~(3+) phosphor is ~5D_0 → ~7F_2 forced hypersensitive electric dipole transition which indicates the deviation of pyrochlore A-site from inversion symmetry. The present quaternary pyrochlore phosphors show strong red luminescence (~612 nm) under near UV (394 nm) and blue light (465 nm) excitations.