The Importance of Organic Ligands around Metal Nanoparticles towards Vapor Sensing

DALFOVO, MARIA C.; IBANEZ, F. J.

New Orleands

Congreso; Meeting Pittcon 2015; 2015

The organic ligands surrounding metal nanoparticles (NPs) not only provide stability and control growing during the synthesis but also, creates a flexible platform for sensing volatile organic compounds (VOCs). In this work we chemically synthesized surfactant (tetraoctylammonium bromide)-coated Au NPs and assemble them as films for the detection of VOCs via distinct changes in plasmon band, interparticle distance, and film structure. For instance, changes in distance between NPs upon VOCs have been usually speculated on the basis of indirect results such as changes in film current or plasmon band. Here, we performed in-situ GISAXS and SAXS experiments in order to unambiguously monitor interparticle distance and film structure upon measured concentrations of polar (ethanol) and non-polar (toluene) vapors. Results show distinct film behavior depending on both; the nature of the analyte vapor and organic alkyl chain. In this presentation I will discuss the importance of film flexibility provided by the organic matrix during VOCs sensing. I will show how the organic alkyl chains are responsible of film restructuring, changes in distance between NPs, and distinct plasmon shift towards red and blue depending on the polarity of the vapor analyte.