Luminescent Polymeric Dispersions and Films Based on Oligonuclear Lanthanide Clusters

The successful embedding of different amounts and types of hydrophobic rare earth clusters (Ln = Y, Pr, Eu, Sm, Nd) in various polymer matrices via miniemulsion polymerization is presented. The resulting cluster-polymer hybrid nanoparticles are spherical in shape and possess a narrow size distribution, as investigated by photon cross correlation spectroscopy (PCCS) and transmission electron microscopy (TEM). The exact Ln-content in the nanoparticles is exemplarily investigated for Eu- and Nd-containing polymer dispersions via inductively coupled plasma-optical emission spectrometry (ICP-OES). As a result of encapsulation more than 1000 mg . L-1 of the hydrophobic Ln-duster are successfully dispersed in water. The photophysical properties of the emulsion show the successful avoidance of water from the vicinity of the clusters. Furthermore, a very efficient energy transfer from the ligand and polymeric unit to Eu3+ ions can be observed in dispersion. Based on the different glass transition temperatures (T-g) of the applied polymers, monolayers of the nanoparticles and efficient luminescent thin polymer films are obtained by spin coating.