The second problem has been that these connected molecules have failed to exhibit the predicted electrical properties when tested without a conducting solution. Physicists attempting these measurements avoided using electrolyte solutions because the applied current would leak into the surrounding solution. Lindsay and his team solved this problem by applying an insulating coating to the entire probe, except its very tip, so there was minimal electrical contact with the solution.
According to Lindsay, the solution is required to make the process work because, without it, the initial insulating property of the molecule prevents the first electron from ever jumping on to the molecule, a kind of “Catch-22.?Ions in the solution “jiggle?the molecule enough to bring about an unusual configuration of the molecule that does allow the electrons from the electrodes to jump on to the molecule, a process first pointed out by Rudy Marcus of Cal Tech (for which he was awarded the 1992 Nobel prize in chemistry).
The oligoaniline molecule the team tested has three electrical states: a neutral state where it is an insulator, a second state where electrons are removed to oxidize the molecule and make it a conductor, and a third state where more electrons are removed and turn it back into an insulator. By measuring the connected molecule in a sulfuric acid solution, the team was able to make reproducible measurements showing all three states by measuring the current thr
Source:Arizona State University