The findings will be discussed in a presentation by Lindsay on February 18 at the American Association for the Advancement of Science annual meeting in Washington, D.C. in an 8:30 a.m. session entitled "Frontiers in Bioinspired Materials and Nanosystems." The findings will also be reported in a forthcoming edition of the American Chemical Society's journal Nano Letters.
Lindsay's team reports achieving an experimental result that physicists have been trying to detect for a long time - negative differential resistance in a single molecule attached to electrodes.
The specifically designed molecule, a hepta-aniline oglimer, belongs to a group of molecules that biochemists have long believed to be capable of being molecular switches, but that have failed to exhibit those properties in conductance experiments. The team solved the problem by developing a technique where the molecule could be tested in an electrolyte solution, a condition that past experiments have never attempted because of the problem of interaction between the solution and the electrodes.
"Almost everything we know about charge transfer in molecules is based on measurements made with the molecules suspended in solution," Lindsay said. "Chemists have understood for a while that the solvent itself plays a major part in charge transfer processes - the ions in the solution are necessary to make the process happen.
"Yet almost every 'molecular electronic' measurement made to date has been made in a vacuum or other conditions that suppress solvent-mediated events. It's no wonder that we could not get reliable results,"
Contact: James Hathaway
Arizona State University