Korean Journal of Materials Research ISSN:1225-0562(Print) 2287-7258(Online) 한국재료학회지

BaMoO₄:Tb³⁺ phosphor powders were synthesized with different concentrations of Tb³⁺ ions using the solid-state reaction method. XRD patterns showed that all the phosphors, irrespective of the concentration of Tb³⁺ ions, had tetragonal systems with two main (112) and (004) diffraction peaks. The excitation spectra of the Tb³⁺-doped BaMoO₄ phosphors consisted of an intense broad band centered at 290 nm in the range of 230-330 nm and two weak bands. The former broad band corresponded to the 4f⁸ →4f⁷5d¹ transition of Tb³⁺ ions; the latter two weak bands were ascribed to the ⁷F₂→ ⁵D₃ (471 nm) and ⁷F₆→ ⁵D₄ (492 nm) transitions of Tb³⁺. The main emission band, when excited at 290 nm, showed a strong green band at 550 nm arising from the ⁵D₄→ ⁷F₅ transition of Tb³⁺ ions. As the concentration of Tb³⁺ increased from 1 to 10 mol%, the intensities of all the emission lines gradually increased, approached maxima at 10 mol% of Tb³⁺ ions, and then showed a decreasing tendency with further increase in the Tb³⁺ ions due to the concentration quenching effect. The critical distance between neighboring Tb³⁺ ions for concentration quenching was calculated and found to be 12.3 Å, which indicates that dipoledipole interaction was the main mechanism for the concentration quenching of the ⁵D₄→ ⁷F₅ transition of Tb³⁺ in the BaMoO₄:Tb³⁺ phosphors.