Research on fluorescence spectra and structure of single-phase 4SrO•7Al2O3:Eu2+ phosphor prepared by solid-state reaction method

In the view of material physical chemistry, the solid-state reaction process and phase-forming rule of 4SrO . 7Al(2)O(3) have been studied. It is verified that 3SrO . Al2O3 which is rich in strontium is formed firstly at approximate to 1000 degrees C, and with the calcining temperature going up to 1300 degrees C gradually, aluminates rich in strontium change to the rich in aluminum in turn. In other words, strontium aluminates are found in the order from 3SrO . Al2O3, SrO . Al2O3 to 4SrO . 7Al(2)O(3) and SrO . 6Al(2)O(3), and the aluminate is 4SrO . 7Al(2)O(3), which exists steadily at 1300 degrees C. The synthesis conditions of single-phase 4SrO . 7Al(2)O(3) are determined, and the data of X-ray powder diffraction and lattice structure of 4SrO . 7Al(2)O(3), which crystallizes in the orthorhombic Pmma space group with a = 24.765 Angstrom, b = 8.478 Angstrom and c = 4.882 Angstrom are presented. Also the differences of fluorescence spectrum between phosphor 4SrO . 7Al(2)O(3):Eu2+ and phosphor SrO . Al2O3:Eu2+ are discussed. And the reliable basis is provided for the synthesis and determination of the new blue-green phosphor 4SrO . 7A(l)2O(3):Eu2+ with high efficiency. (C) 1998 Elsevier Science S.A. All rights reserved.