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. - Highlights: • A series of lanthanide-doped polyoxometalate microtubes have been firstly synthesized. • The Ln-SiW₁₂ microtubes were chelated with HQ in a post-synthesis step. • The LnQ-SiW₁₂ microtubes show characteristic NIR luminescence through antenna effect