Semimetal Polymer Discovered
In most situations, we find that plastics are electrical insulators, but in the seventies it was discovered that some were actually semiconductors. Now researchers at Linköping University, and many other institutions around the world, have found a polymer that is a semimetal, which could affect the future use of thermoelectric devices.
Semimetals are a family of materials resting between metals and semiconductors, characterized by a small bridge between the conduction electron bands of their atoms, and the valence band. This means they do not have a band gap, but they also do not have much room for electrons at the energy level needed to conduct. The idea that a polymer can be a semimetal was first hypothesized a few years ago, when a high thermoelectric effect was measured in a polymer. This indicated it was a semimetal, but was not proof on its own. Bow the team of twenty scientists from around the world have confirmed that a doped version of the plastic PEDOT is a semimetal.
The high thermoelectric effect could have some interesting implications, in part because polymers are cheaper to manufacture, while the metals used in thermoelectric devices are quite rare and expensive. Now that we know the job can be done with polymers, a new field of organic electronics could grow.
Source: Linköping University