Amplifying Photoluminescence of Lanthanide-Doped Nanoparticles by Iridium Phosphonate Complex

Amplifying the photoluminescence of lanthanide-doped nanoparticles by antenna materials can bridge the gap in properties between pristine nanoparticles and those required by practical applications. However, high-performance antennas with ideal stability are rather few. Here, we report a new type of iridium (Ir)-based phosphonate complex as an antenna to amplify the near-infrared luminescence of lanthanide-doped nanoparticles. Unlike conventional antennas, the Ir complex, with a quasi-spherical structure and pendent phosphonic groups, can resist the aggregation-caused quenching and firmly anchor on nanoparticles. Near-infrared luminescence of lanthanide-doped nanoparticles can be stably amplified up to 130 times by the complex, which should be due to short-range energy transfer from the triplet state of the complex to lanthanide ions. These findings may pave a new fundamental way to amplify the luminescence of lanthanide-doped nanoparticles and promote applications of the nanoparticles.