Recent Progress in Cyano Complexes of Platinum and Gold as Sensitizers of Lanthanide Emissions

Lanthanide ions have sharp characteristic emission in the visible and near-infrared (NIR) ranges, long luminescence lifetimes, and large Stokes shifts, which make them very attractive candidates for the development of optical devices, including as light conversion materials. The potential for these and other applications requires a new approach in the choice of chromophores suitable for lanthanide sensitizations. Although great progress has been made to circumvent the problem of inefficient direct f-f absorption in lanthanide systems through the process of sensitization, the conversion efficiency of the absorbed photon to visible emission is typically low, except in a few cases. A class of chromophores involving transition metal complexes is emerging as a suitable choice as a sensitizer for lanthanide ion acceptors. A major advantage afforded by these chromophores is their ability to sustain a better energy match-up with most Ln3+ acceptor states. Unique advantages of metal complexes over organic chromoph...