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 5D0→7F1 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.