Four states molecular device – FOST

Molecular-scale electronics have attracted a growing interest, both for basic science at the nanoscale and for possible applications in nano-electronics. In the first case, molecules are quantum objects by nature and their properties can be tailored by chemistry opening avenues for new experiments. In the second case, molecule-based devices are envisioned to complement silicon devices by providing new functions or already existing functions at a simpler process level and at a lower cost by virtue of their self-organization capabilities.

The most common approach is to use redox molecules to store charges like in flash-memory. We propose an interesting alternative which stores information by tuning the conformation of an organic molecule.

Previous works have shown that upon a given excitation, molecules can undergo conformational changes. If such conformers are associated with conductivity levels of the molecule, this effect can be used to make molecular switches and memories. Reports in this direction are scarce of not sounds.

In this project, we aim at extending the concept of conformational memory by synthesizing dedicated molecules with two addressable subunits that can undergo conformational changes upon irradiation and / or protonation. Such molecules would present 4 different electronic states (i.e 2 bits memory), that could be used for implementing basic logic function at the single molecule scale.

This pluri-disciplinary project is based on two complementary approaches:
- The conformation / electronic properties relationship of the molecules (synthesis, characterization and theoretical calculations)
- The dependence of conductivity measurements on the scale of measurement (from the micron scale down to the single molecule scale)

The development of new molecular memories is not only an exciting academic challenge but also a possible alternative to the miniaturization of semiconductor devices:
- The function is not altered by the size reduction, since it is an intrinsic property of a single molecule
- The time stability of our system should lead to unprecedented non volatile memories
- The integration of basic logic functions on a single component is possible using a four state molecular device