Advances in molecular electronics
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and the Univ. of Konstanz are working on storing and processing information on the level of single molecules to create the smallest possible components that will combine autonomously to form a circuit.
As recently reported in Advanced Science, the researchers can switch on the current flow through a single molecule for the first time with the help of light.
Dr. Artur Erbe, physicist at the HZDR, is convinced that in the future molecular electronics will open the door for novel and increasingly smaller—while also more energy efficient—components or sensors: “Single molecules are currently the smallest imaginable components capable of being integrated into a processor.” Scientists have yet to succeed in tailoring a molecule so that it can conduct an electrical current and that this current can be selectively turned on and off like an electrical switch.
This requires a molecule in which an otherwise strong bond between individual atoms dissolves in one location—and forms again precisely when energy is pumped into the structure. Dr. Jannic Wolf, chemist at the Univ. of Konstanz, discovered through complex experiments that a particular diarylethene compound is an eligible candidate. The advantages of this molecule, approximately three nanometers in size, are that it rotates very little when a point in its structure opens and it possesses two nanowires that can be used as contacts. The diarylethene is an insulator when open and becomes a conductor when closed. It thus exhibits a different physical behavior, a behavior that the scientists from Konstanz and Dresden were able to demonstrate with certainty in numerous reproducible measurements for the first time in a single molecule.