Using a Vapor‐Phase Surfactant to Control Gold Metal Plate Growth

Hexamethyldisilazide‐1,3‐diisopropylimidazolidine‐2‐ylidenegold(I) (1) is used to deposit gold microplates with (111) faces. In the absence of any secondary vapor‐phase surfactant, these plates show secondary nucleation and growth of gold metal nanoparticles on the (111) faces. When tetrahydrothiophene (THT) is used as a secondary, vapor‐phase surfactant, plate size increases, and secondary nucleation is controllable by temperature. Deposition of gold microplates at 370 °C using a 45 mTorr overpressure of THT shows the best experimental results, growing 20 µm² plateaus with no apparent secondary nucleation. Computational modelling demonstrates that THT is a stronger surfactant than the carbene ligand (from the gold precursor) due to steric hindrance from the alkyl groups present in the carbene ligand.