Tubular solids of lanthanide-doped polyoxometalates in micrometer-scale: synthesis and NIR-luminescent properties

A series of lanthanide-doped polyoxometalate microtubes, Ln-SiW12 (Ln=Nd, Dy and Yb), have been synthesized, and characterized by X-ray diffraction, elemental analysis and thermogravimetric analysis. In the microtubes, the lanthanide cations combine with polyanions through electrostatic interaction. Furthermore, the lanthanide-doped microtubes were chelated with 8-hydroxyquinoline (HQ) in a post-synthesis step (designed as LnQ-SiW12). The LnQ-SiW12 show characteristic near-infrared (NIR) luminescence, corresponding to Ln3+ ions due to efficient energy transfer from Q to the Ln3+ ions through antenna effect.