Molecular switches for communication sectror

The principle is to insert in the structure of a mixed valence compound a molecular bridge with two possible states: "ON" (i.e. a non-zero electronic coupling between extremities), and "OFF" (i.e. no coupling). Thus we monitor the photo induced electron transfer process where an electron moves from one end to the other of the molecule.

Alternative materials and operating principles for the elaboration and communication of data in electronic circuits and optical networks must be identified. Organic molecules are promising candidates for the realization of future digital processors. Their attractive features are the miniaturized dimensions and the high degree of control on molecular design possible in chemical synthesis. Indeed, nanostructures with engineered properties and specific functions can be assembled relying on the power of organic synthesis. In particular, certain molecules can be designed to switch from one state to another, when addressed with chemical, electrical, or optical stimulations, and to produce a detectable signal in response to these transformations. Binary data can be encoded on the input stimulations and output signals employing logic conventions and assumptions similar to those ruling digital electronics.

Thus, binary inputs can be transduced into binary outputs relying on molecular switches. Presently, these simple molecular processors are far from any practical application. However, these encouraging results demonstrate already that chemical systems can process binary data with designed logic protocols. Further fundamental studies on the various facets of this emerging area will reveal if and how molecular switches can become the basic components of future logic devices. After all, chemical computers are available already. We all carry one in our head! And the molecules which can act as the molecular switches are fullerene derivatives, biological molecules, DNA base guanine etc.