Advancements in rare earth metal-organic frameworks: Harnessing the power of photonics and beyond

Metal-organic frameworks (MOFs) represent an emerging category of porous crystalline materials, notable for their high porosity, adjustable pore sizes and elevated Lewis acid contents. Rare earth MOFs (RE-MOFs), a specific subset of MOFs, use rare earth ions or clusters as central metal linkers, rendering advantages of both MOFs and rare earth ions. The distinctive feature of rare earth ions with unfilled 4f electron shells endows them with elevated coordination numbers and unique photophysical characteristics. Besides, the diversity of ligands within MOF frameworks effectively channels the antenna effect to sensitize the rare earth ions, resulting in enhanced photon emission, making RE-MOFs a kind of promising material in the photonics field, including photocatalysis, fluorescent probes, light-emitting, temperature sensing, near infrared (NIR) emission and more. This review presents the recent progress of photonic RE-MOFs creatively categorized by rare earth elements to demonstrate their great potential in photonics. The inherent correlation between structure of RE-MOFs and their photonic properties are systematically and comprehensively discusssed. Moreover, we highlight several key development directions of advanced photonic RE-MOFs to guide the further design.