Influence of reaction parameters on the luminescence properties of monodisperse NaGd_（1-x-y）（WO₄）₂:xEu³⁺,yTb³⁺ phosphor by molten salt synthesis

Weiqin Xiao¹，Luqiao Yin²，Jipeng Zhou²，Fang Lei¹，Ying Shi¹，Jianjun Xie¹，Lei Zhang¹

1. School of Materials Science and Engineering,Shanghai University2. Key Laboratory of Advanced Display and System Applications,Ministry of Education (Shanghai University)

摘 要：Eu³⁺ activated and Eu³⁺, Tb³⁺ co-activated monodisperse sodium double tungstates NaGd（WO4）2 phosphors were prepared by molten salt method at 750 ℃ for 10 h using NaCl as a flux. The crystal structure and morphology of the as-synthesized phosphors were measured by XRD and SEM, respectively. The photoluminescence properties were characterized by PL spectra, decay lifetime and CIE. The presence of NaCl plays an important role in the morphology and luminescence properties. In this work,NaCl and one of the raw material Na₂ CO₃ in a certain proportion will form a low eutectic salt to decrease the reaction temperature and benefit the formation of monodisperse NaGd（WO₄）₂ crystals. The color of Eu³⁺ and Tb³⁺ co-doped NaGd（WO₄）₂ phosphors can be tuned from creamy white to orange, red and green by adjusting the doping concentration of rare earth ions, since the emission contain the broad blue-green emission origin from NaGd（WO₄）₂ host and characteristic red and green emission origin from Eu³⁺ and Tb³⁺ ions. The electroluminescent spectra and CIE measurement shows that the LED device with NaGd_（1-x）（WO₄）₂:xEu³⁺（x = 0.24） phosphor can be excited by 365 nm and 380 nm LED chip, and their CIE coordinate is（x = 0.45, y = 0.45） and（x = 0.36, y = 0.37）, Ra is 80.3 and 86.3, T_c is 3196 and4556 K, respectively. As a single-component phosphor, NaGd（WO₄）₂:Eu³⁺,Tb³⁺ have potential application in UV-pumped WLEDs.

关键词：