A novel trimeric cationic surfactant as a highly efficient capping agent for the synthesis of trisoctahedral gold nanocrystals

A novel trimeric cationic surfactant tri(dodecyldimethylammonioacetoxy)diethyl-triamine trichloride (DTAD) has been used as a highly efficient capping agent to synthesize trisoctahedral (TOH) Au nanocrystals (NCs). Very low concentration of DTAD (0.2 mM) can favor the formation of TOH Au NCs due to excellent interfacial adsorption ability of DTAD. The strong electrostatic interaction between the multi-charged head groups and Au facets and the hydrogen bonding among the head groups together with the stronger hydrophobic interaction between hydrocarbon chains account for high efficiency of DTAD. This study can help guide the rational design of task-specific capping agents with desired efficiency and property and minimize the negative environmental effects of surfactants during NC fabrication.