SYNTHESIS AND pH DEPENDENT OPTICAL PROPERTIES OF Au NANOPARTICLES CAPPED WITH MERCAPTOPROPIONIC ACID

摘要

In recent years, there has been considerable interest in the synthesis of nanometer sized semiconductor and metal colloids due to their unique optical, and electrical properties, as well as their potential applications in the future photonics and electronics. A large number of methods have been developed for preparing these nanoparticles. Among those, chemical reduction of the relevant metal salt in the presence of suitable surfactants and/or stabilizers is one of the most commonly used method for synthesizing the metal nanoparticles. These stabilizers can be ions or polymers which are adsorbed on the nanoparticles surface, in order to prevent self-aggregation of individual nanoparticles. However, most of these colloidal nanoparticles can not be isolated and redispersed in solvents after precipitation until recent report by Brust and co-workers. In their method, they used a phase transfer reagent to extract the metal ions from aqueous solution, then carried out the reduction with NaBH_4 in the presence of an alkanethiol, producing a stable colloids of thiol-capped gold nanoparticles dispersed in organic phase.