Development of zeolite-derived novel aluminosilicate phosphors

In this research, zeolite-derived aluminosilicate phosphors were synthesized through the ion exchange route. Red light-emitting property of Eu³⁺-doped aluminosilicate phosphors were discussed from a view point of the Eu content, heat-treatment condition and the oxidation state of Eu ions. The crystalline phase of the host aluminosilicates could be successfully controlled as designed based on the published NaAlO₂–SiO₂ binary phase diagram. Orange-red emission peaks derived from the ⁵D₀→⁷F_j (j=0, 1, 2, 3, 4) transition of Eu³⁺ were observed around 590–700 nm, and 4f⁶5d→4f⁷ transition of Eu²⁺ was observed at around 400–500 nm. The relative intensity I(⁵D₀→⁷F₂) of the dominant emission peak at 612 nm increased consistently with the Eu content. The results of the XANES spectroscopy analysis revealed that Eu²⁺ ion in the 1400 °C as heat-treated host aluminosilicate were successfully converted to Eu³⁺ by the additional annealing at 1100 °C. The Eu contents and heat-treatment conditions were determined to exhibit the best performance as a red phosphor, which were 10 wt% and 1500 °C, respectively