Floating Films On Liquid Mercury: New Results May Lead To Advances In Nanotechnology, Molecular Elec
Scientists from the U.S. Department of Energy’s Brookhaven National Laboratory, Bar-Ilan University, and Harvard University have grown ultrathin films of organic chain molecules on the surface of liquid mercury and discovered that the molecules form ordered structures.
Source: Science DailySimilar to sixty years ago when fundamental studies of silicon paved the way to the semiconductor-electronics age, these results help to build a foundation for the development of tiny circuits built using organic molecules — called molecular electronics — a field believed to be the future of many electronic applications.
The scientists are participating in an ongoing program at Brookhaven to grow ultrathin organic films on solid and liquid surfaces. They are most interested in films that have controllable properties at a thickness of just a few nanometers, or billionths of a meter, so that they can engineer technologies based on these properties. In addition to being useful for molecular electronics development, ultrathin organic films are becoming increasingly important for many other emerging technologies, such as flexible electronic displays and advanced biotechnological materials that can, for example, mimic the function of cell membranes.
“We decided to use liquid mercury as a surface, instead of a solid,” said Brookhaven physicist Benjamin Ocko, the lead author of the study, reported in the January 12, 2005, online edition of Physical Review Letters. “Liquid surfaces are disordered, hence they do not impose a structure of their own on the film. This makes them important testing grounds for organic thin film growth.”
The researchers filled a small tray with a layer of liquid mercury and deposited a controlled amount of the organic molecules, called alkyl-thiol, onto its surface. “We chose alkyl-thiol because one end of each molecule is terminated by a sulfur atom that bonds strongly to metal surfaces,” explained Henning Kraack, a physicist from Bar-Ilan who participated in the study. “Thiol molecules have been studied extensively on gold surfaces, but the exact nature of the sulfur-gold bond has remained controversial. One of our main goals was to determine the nature of the bond between a similar pair: sulfur and mercury.”
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