The effect of various codopants on the cathodoluminescent properties of Y 2O 3:Eu phosphors

Abstract

Due to its high luminescence efficiency, high saturation current, and chemical stability, Y 2O 3:Eu 3+ is one of the red phosphor candidates for field emission displays (FED). However, Y 2O 3:Eu 3+ doesn't have enough brightness at low voltage for a FED and doesn't pure a red, but a reddish orange, color. In order to enhance the brightness and the color purity, we studied the photoluminescence, cathodoluminescence, X-ray diffraction, scanning electron microscopy, and current-voltage characteristics of Y 2O 3:Eu 3+ for various Eu 3+ concentrations, temperatures, surrounding atmospheres, Al 3+ additions, and Ca 2+, Cu 2+, Cr or In 3+ codopings. The brightness was improved when the dopant was added in the form of Eu 3+ with Al 3+ rather than Eu 3+ only. The increase in the brightness could be understood in terms of the decrease in the crystal defects of the host material. Adding other codopants generally decreased the brightness without changing the normalized emission spectra.