Synthesis and photoluminescence properties of Yb2+ doped Ba-5(PO4)(3)Cl phosphor for white light-emitting diodes

Abstract

Yb2+ ion doped Ba-5(PO4)(3)Cl phosphor was synthesized by solid state reaction. Four distinct absorption bands were observed in the Ultraviolet (UV) light region due to the electronic transitions of Yb2+ ion from S-1(0) ground state to F-2(5/2)(t(2g)), F-2(5/2)(e(g)), F-2(7/2)(t(2g)), and F-2(7/2)(e(g)) excited states. The main emission wave-length of the phosphor was around 630 nm. The optimized Yb2+ ion concentration was 0.2 mol% (lambda(exc.) = 400 nm). The calculated critical distance was about 8.729 angstrom and the concentration quenching was observed above 0.2 mol% due to the electric dipole-dipole interaction. (C) 2009 Elsevier B.V. All rights reserved.