Facile synthesis of alginate-based calcium tungstate composite: A thermally stable blue emitting phosphor

The alginate-based calcium tungstate composite was fabricated by a facile and eco-friendly one-step crosslinking process combining with the freeze-drying method. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscope, X-ray diffraction, thermogravimetric analysis, UV-vis diffuse reflectance spectrum and photoluminescence (PL) were employed to characterize the structures, morphologies, thermal stabilities, and optical properties of the synthesized composite materials. The obtained results demonstrate that the alginate-based calcium tungstate composite presented a special porous network architecture with tetragonal scheelite-type calcium tungstate microspheres attached. A possible synthesis mechanism was proposed based on the experimental data. Moreover, the PL data confirmed the broadband emission of the composite with its maximum at 438 nm that located in the blue emitting region. This study provides the alginate-based calcium tungstate composite with unique morphology and good thermal stability as well as lays a foundation for its application in the field of PL.