Recent advances in lanthanide-based POMs for photoluminescent applications

Since the first formation of the famous "Peacock-Weakley" anions [Ln(W₅O₁₈)₂]^8/9-, a steady stream of breakthroughs have been made in the chemistry of multitalented lanthanide (Ln)-based polyoxometalates (POMs) for their potentially desirable properties. In particular, Ln^III ions are generally recognised as the "vitamins of the modern industry" owing to their ability to cover a wide emission range, endowing Ln-based POMs with great potential for versatile and diverse luminescence-related applications. In this frontier, we discuss the synthesis strategies and intramolecular energy transfer in Ln-based POM derivatives. Then, the progressive improvements achieved with Ln-based POMs in photoluminescence applications are highlighted, focusing mainly on luminescent and fluorescent probes. Finally, the challenges for Ln-based POM materials for photoluminescence applications are discussed.