Tb L₃-edge X-ray Absorption Near-edge Structure Spectroscopic Analysis of Terbium-doped Phosphor Compoundsfor Plasma Display Panel Applications

We have analyzed Tb L₃-edge x-ray absorption near-edge structure spectra of Tb-doped phosphor compounds for plasma display panel applications. Intensity and lifetime of the green emission from the Tb³⁺:⁵D₄→⁷F₅ transition were measured with respect to nominal terbium concentration in the host compounds, i.e., YBO₃, YPO₄,and Y₄Al₂O₉, all of which were made through the solid-state reaction. Typical concentration quenching was evident on the fluorescence intensity and the fluorescing level lifetime in our samples. From the analyses of white line absorption peaks at TbL₃-edge, it was verified that terbium is essentially trivalent in all the samples, even invery highly concentrated ones. Thus, this implies that the concentration quenching was not caused by presence of mixed-valent states of terbium. Instead, it is believed that anonradiative energy transfer route among Tb³⁺ ions might be responsible for thebehavior.