Luminescent properties of BaAl12O19:Tb, Dy phosphors prepared by sol-gel method.

BaAl12O19:Tb, Dy phosphor was prepared by the sol-gel technique using citric acid as a complextant. XRD was used to characterize the relevant crystallization behavior of the phosphor. The luminescence properties and energy transfer between Tb3+ and Dy3+ were investigated. The results revealed that energy transfer exists between Dy3+ and Tb3+ at appropriate Tb3+ concentrations. The emission intensity of Tb3+ increases and energy transfer happens from Dy3+ to Tb3+ ions at the higher content of Tb3+ when Tb3+ and Dy3+ ions were co-doped. BaAl12O19 phosphors doped with Tb3+ or Dy3+ ions only were studied to compared with BaAl12O19:Tb, Dy phosphors. The results showed that the maximum excitation peak of BaAl12O19:Tb is 240 nm and the emission spectrum consists of four peaks at 490, 545, 590, and 625 nm, originating from 5D4 --> 7FJ (J = 6, 5, 4, 3) transitions of Tb3+ ion, respectively. The excitation peaks of BaAl12O19:Dy are at 291, 324 nm and the emissions of Dy3+ are at 370, 447 and 578 nm, originating from 4F9/2 --> 6P5/2, 4F9/2 --> 6H15/2 and 4F9/2 --> 6H13/2 transitions of Dy3+ ion, respectively.