Switching between different conformers of a molecule: Multilevel memory elements

We report voltage-driven electrical histability in an organic semiconductor, namely Ponceau SS. Conductance switching to different levels or multilevel switching in devices based on thin-films is due to different density of high-conducting molecules. In a monolayer of Ponceau SS, we have observed one low-conducting and two high-conducting states. This is due to three configurable planes of the molecule exhibiting at least two stable high-conducting conformers. Apart from establishing conductance switching to be a molecular phenomenon, the multilevel conductance in a monolayer shows that a single molecule can exhibit multilevel memory application. (c) 2007 Elsevier B.V. All rights reserved.