Red Emitting Ca(2)GeO(4):Eu(3+) Phosphors for Field Emission Displays

A novel red emitting phosphor, Eu(3+) -doped Ca(2)GeO(4) was prepared through the solid state reaction. We also replace Ca(2+) with Mg (2+) and Ba(2+) ions and add Li(+) , Al(3+) ions as charge compensators in the Ca(2)GeO(4) host to improve the luminescence properties of Ca(2)GeO(4):Eu(3+) phosphor. XRD, FE-SEM, photoluminescence and cathodoluminescence spectra were utilized to characterize the samples. XRD reveals that pure Ca(2)GeO(4) phase can be obtained at 1250 degrees C and all the above cation substitutions can be achieved in a certain concentration range except for Ba(2+) ion. FE-SEM images indicate that the Ca(1.99)GeO(4):0.01Eu(3+) sample and its substitutions consist of aggregated particles with size ranging from 0.5 to 2 mu m, and Ba(1.99)GeO(4):0.01Eu(3+) sample is composed of uniform and spindle-like structures with the size ranging from 300 to 500 nm. Under the excitation of ultraviolet light and low-voltage electron beams, the Ca(2)GeO(4): Eu(3+) phosphor shows the characteristic emissions of Eu(3+) ((5)D(0)-(7)F(2) at 613 nm, red). The optimum concentration for the luminescence Eu(3+) is determined to be 0.01 in Ca(2-x)GeO(4):xEu(3+) phosphor. The luminescent intensity can be improved by co-doping the Mg(2+) ions and charge compensators (Li(+) and Al(3+) ) to partially substitute of Ca(2+) ions. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3554726] All rights reserved