New promising phosphors Ba3InB9O18 activated by Eu3+/Tb3+

Borate Ba3InB9O18 (BIBO) has been adopted as a host material for phosphors for the first time. Lanthanide ions (Eu3+/Tb3+)-doped BIBO phosphors have been synthesized by solid-state reaction and luminescent properties investigated under ultravoilet (UV) excitation. For red phosphor BIBO:Eu, dominant emission peaking at 590 nm was attributed to D-5(0) -> F-7(1) transition of Eu3+, which confirmed that the local site of Eu3+ occupied by In3+ ion in BIBO crystal lattice is at inversion symmetry center. Optimum Eu3+ concentration of BIBO:Eu under UV excitation with 227 nm wavelength is around 40%. The green phosphor BIBO:Tb showed bright green emission at 550 with 232 nm light excited and optimal of Tb3+ concentration measured in BIBO is about 8%. The corresponding luminescence mechanisms of Ln-doped BIBO (Ln = Eu3+/Tb3+) were analyzed. The luminescent intensity of Tb3+ can be significantly improved by co-doping of Bi3+ in the BIBO:Tb lattice. The likely reason was proposed in terms of the different interactions of the host lattice with these ions, and of these ions with each other. (c) 2009 Elsevier B.V. All rights reserved.