Motivation

Individual TbPc2 SMM imaged by STM on a Cu(100) surface (image size 200 x 200 nm). The inset displays the four-lobed molecular structure (from Stepanow et al., J. Am. Chem. Soc. 2010, 132, 11900-11901).

A nanoscale electronic device entrapping an individual Fe4 SMM. The gate electrode (white) allows to modulate the electron trasport properties, yielding a molecule-based field-effect transistor (from Zyazin et al., Nano Lett. 2010, 10, 3307-3311).

Scientists from many diverse disciplines (chemistry, physics, biology, etc.) are used to work with very large assemblies of molecules. For instance, one microgram (0.000001 g) of ferritin – a high molecular weight protein (MW > 400,000 Da) – already contains more than one thousand billion molecules! A very sensitive spectroscopic techniques, Electron Paramagnetic Resonance (EPR), allows to detect down to 10E11 radical species, a huge number still!

What is the minimum number of molecules that can be experimentally detected and studied?

In the last 20 years techniques have become available which enable to probe the properties of one individual molecule. They include the well-known Scanning Probe Microscopies such as AFM (Atomic Force Microscopy), STM (Scanning Tunneling Microscopy) or MFM (Magnetic Force Microscopy). Alternative, more exotic approaches are based on lithographically-fabricated electrodes or nanogaps, which can be used to trap individual molecules.

These methods have demonstrated that single molecules can perform all the basic electronic functions, i.e. rectification (molecular diodes), amplification (molecular transistors) and storage (molecular memory units). The possibility to use single molecules as active components might then revolutionize electronic devices, meeting the ever-increasing demand on device complexity and versatility, processing speed and miniaturization.

At CorniaGroup, we investigate chemical strategies to assemble molecule-based devices. Our research requires to master organic and inorganic synthesis, solid-state characterization techniques and surface science, as well as computational methods and modelling.

In our Laboratory, we deal mainly with certain molecular species which are capable of storing magnetic information at the molecular level and are therefrom named Single-Molecule Magnets (SMMs). Although the unique magnetic properties of SMMs were disclosed in the early 1990s, so far nobody has been able to realize a crucial experiment which consists in "writing" or "reading" the magnetic information stored in one molecule. In order to do so, SMMs have to be individually connected to the external world. We are currently pursuing different strategies to carry out such a sophisticated “wiring” in a clean, reproducible and controllable fashion.