Reverse self-assembly: (111)-oriented gold crystallization at alkylthiol monolayer templates.
It has long been known that thiol-terminated molecules self-assemble as commensurate monolayers on Au(111) surfaces. By spreading floating octadecanethiol monolayers on aqueous solutions of chloroauric acid (HAuCl4) and using x rays to reduce the gold ions as well as to probe the structure, we have observed the nucleation of (111)-oriented Au nanoparticles at thiol surfaces. This process may be similar to the formation of biogenic gold by bacteria. The thiol monolayer acts as a "soft template," changing its structure as Au crystals form so that there is a sqrt[3]×sqrt[3] commensurate relationship.
Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA.
Ahmet
A
Uysal
Benjamin
B
Stripe
Binhua
B
Lin
Mati
M
Meron
Pulak
P
Dutta