So, just What is Molecular Electronics? And how can it be used to create something interesting?
The field of molecular electronics got going when the idea of using a molecule as a circuit component was proposed theoretically in 1974. Since then, there have been many experiments aimed as using molecules in circuits. Many of these use layers of molecules (not just a single molecule), and due to the way devices are constructed (see Figure 1 below), the critical dimension of the device resides in the same range as many small molecules (2-50 nm).
Figure 1 shows a molecular junction:
Figure 1 shows to conductive layers with a molecular layer between them. In this case, a layer of ~2 nm is shown (2 molecules thick).
So, the main component, the Molecular Junction, is really a nano molecular sandwich, with conductors as the bread.
In order for electrons to complete the electronic circuit between the two conductors, they must flow across or through the molecular layer, meaning that a molecular junction incorporates molecules directly into the circuitry.
What does a molecular junction look like? Figure 2 shows a SIM card containing two molecular junctions in an adapter designed to enable electrical contact to the devices.
Figure 2: Photograph of a molecular junction:
The molecular junctions shown above can be integrated into analog circuitry easily by putting a SIM card holder onto a PCB board with the rest of the circuit.