One-step synthesis of Sc2W3O12:Eu3+ phosphors with tunable luminescence for WLED

Sc2W3O12 is an important host matrix for rare-earth doped luminescence. However, the conventional method to prepare the material is solid-state reaction, which results into coarse and irregular morphologies. In this work, Eu3+ doped Sc2W3O12 phosphors with high crystallinity and pure phase were successfully synthesized via one-step hydrothermal method. It was found that the crystalline phase changed from Sc2W3O12 phase to Na4Sc2(WO4)(5) phase when the molar ratio between Sc(NO3)(3) and Na2WO4 decreased. The temperature-dependent X-ray diffraction analysis was performed to prove the negative thermal expansion property of Sc2W3O12. A systematic study on the effect of reaction time, temperature and Eu3+ doping concentration was explored. It was also found that the as-prepared samples displayed tunable emission colors, ranging from blueish white to orange red. Particularly, the white light emission with the chromaticity coordinate of (0.3395, 0.3289) can be realized in Sc2W3O12: 5% Eu3+. What's more, the photoluminescence properties of the samples were investigated under different ambient temperatures between 97 and 280 K. The result clearly showed energy transfer between Eu3+ and WO42-. The above results suggested that Sc2W3O12:Eu3+ can be excellent candidate for solid-state lasing, panel display and WLEDs.