Synthesis of Alkaline Terbium Tungstates and Molybdates by Solid-State Reaction and their Luminescence Properties

Abstract

Alkaline terbium tungstates were investigated as a green-light-emitting phosphor for n-UV LEDs. We prepared the compounds using a solid-state reaction, and investigated their luminescence properties. We also investigated the effect of substitution by alkali metal ions and Mo⁶⁺ ions to improve the emission intensity. The synthesized phosphors showed sharp excitation and emission spectra due to the 4f-4f electronic transition of the Tb³⁺ ions. The luminescence intensity was increased by substituting with Na⁺ ions and K⁺ions at concentrations of 40% and 6%, respectively. However, the emission intensity substantially decreased by substituting with Mo⁶⁺ ions. We considered that this is due to shifting of the 5d level in the Tb³⁺ ions by increasing the substituted ion content.