Population Saturation in Trivalent Erbium Sensitized by Organic Molecular Antennae

We investigate sensitization efficiency of near-infrared emission and population saturation of trivalent erbium in erbium quincilinolato complexes photoexcited into the absorption band of the organic sensitizer. At low excitation levels, we find high (similar to 80%) sensitization efficiencies. We observe excited state population saturation at inversion threshold under subnanosecond pumping at the level of one injected photoexcitation per complex.