Crystal Structure and Photoluminescence Properties of CaSr₂Al₂O₆:Eu³⁺Phosphors

Abstract

The novel red-emitting phosphors of Eu3+-activated CaSr2Al2O6:Eu3+ were synthesized by conventional solid state reaction. Crystal structure, characteristic luminescence properties and charge compensators effect (Li+, Na+, K+) are investigated in detail by X-ray diffraction refinement and photoluminescence spectra measurement. CaSr2Al2O6 crystallizes in a cubic structure with the space group of Pa(3)-205, and cell parameter a = b = c = 15.06217(5)angstrom. The difference between the emission spectra of CaSr1.90Al2O6:0.10Eu and Ca0.90Sr2Al2O6:0.10Eu revealed that the Eu3+ ions occupied nonequivalent Sr2+ or Ca2+ sites with different site symmetry. When Eu3+ ions occupied Sr2+ sites without inversion symmetry, the intensity ratio of (D-5(0)-F-7(2))/(D-5(0)-F-7(1)) is higher and thus a better color purity. CaSr1.92Al2O6:0.08Eu(3+) exhibits strong absorption at 394 nm and intense red emission with CIE chromaticity coordinates (0.6408, 0.3581). The critical distance of the concentration quenching and thermal stability are also investigated. (C) 2013 The Electrochemical Society. All rights reserved.