Formation and optical properties of silver perfluorodecanethiolate nanoparticles

This article reports a new catalytic method for preparing nanoparticles of silver thiolate from silver nanoparticles scattered on a ZrO2-coated substrate. Such nanoparticles transform into silver (perfluoro) decanethiolate after immersion in a solution of (perfluoro) decanethiol in heptane. These transformations occur at room temperature and are catalysed by ZrO2. The silver decanethiolate is obtained as lamellar crystals while the silver perfluorodecanethiolate is obtained in amorphous state. The modifications of the sample optical properties due to this latter compound are studied in correlation with its surface morphology, according to different preparation conditions. It is shown that an antireflective effect in addition to the damping of the plasmon band of the silver nanoparticles can be responsible for a large transmittance enhancement in the near-UV and visible ranges. These effects are modulated by the possible oxidation of the silver nanoparticle surface. In the absence of silver oxidation, the silver perfluorodecanethiolate is obtained as contiguous spheroidal nanoparticles, while, in the presence of silver oxidation, this compound is mainly obtained as entangled nanowires.