Nanocomposite Strategy Eliminates Matrix

The narrow spectral width and high quantum efficiency of lanthanide spectral emission make rare-earth-doped nanocrystals good candidates for optical materials. Making composite materials with such nanoparticles requires carefully matching the properties of the particles themselves with those of the surrounding matrix material. Even with well-matched materials, problems can arise when the nanoparticle loading gets too high. Clemson University scientists John Ballato, Jeffrey R. DiMaio, and Baris Kokuoz propose a solution to this problem: They use nanoparticles (often themselves nanocomposites) that carry their own matrix (J. Am. Chem. Soc., DOI: 10.1021/ja800093p). The researchers suggest that organic ligands on the surface of nanoparticles can be cross-linked and thus function as the host material in a nanocomposite. They call their materials omnicomposites because they are formed entirely of composite nanoparticles. They demonstrated their idea using LaF₃ nanoparticles with trifluororvinyl ether ligands on the surface. The nanoparticle loading in the omnicomposite is nearly 80% by weight. The stability of the omnicomposite is similar to that of traditional nanocomposites, but the omnicomposite's emission intensity is eight times higher.