Solving mysteries of conductivity in polymers
Materials known as conjugated polymers have been seen as very promising candidates for electronics applications, including capacitors, photodiodes, sensors, organic light-emitting diodes, and thermoelectric devices. But they’ve faced one major obstacle: Nobody has been able to explain just how electrical conduction worked in these materials, or to predict how they would behave when used in such devices. Now researchers at MIT and Brookhaven National Laboratory have explained how electrical charge carriers move in these compounds, potentially opening up further research on such applications. A paper presenting the new findings is being published in the journal Advanced Materials. Conjugated polymers fall somewhere between crystalline and amorphous materials — and that’s caused some of the difficulty in explaining how they work, says Asli Ugur, an MIT postdoc and lead author of the paper. Crystals have a perfectly regular arrangement of atoms and molecules, while amorphous materials have a completely random arrangement. But conjugate polymers...