Photoluminescence and Crystal Structure of Green-Emitting Phosphor CaSc[sub 2]O[sub 4]:Ce[sup 3+]

Abstract

A new green phosphor, -activated , was developed, which shows green luminescence with a peak wavelength of under excitation with blue light. -activated can be used as a material for color conversion of white-light-emitting diodes (LEDs), which consist of a blue LED, a green phosphor, and a red phosphor, because the luminescence efficiency of this phosphor is comparable to those of commercial phosphors such as . The host crystal of this phosphor has an orthorhombic structure, and the Ce ion probably exists in an eight-coordinated Ca position. We investigated the dependency of the firing temperature and dopant concentration for luminescence intensity and found that the optimum temperature and concentration were and of Ce substituted to the Ca position. The luminescence peak wavelength was shifted toward longer wavelengths by replacing Ca with Mg. In contrast, replacing Ca with Sr resulted in a shift toward shorter wavelengths.