Loo Team Demonstrates New Route to Highly-Conductive Polymers
A research team led by Yueh-Lin Loo, Associate Professor of Chemical Engineering and an associated faculty member in Electrical Engineering, has shows that a simple treatment can raise the conductivity of polyaniline and poly(ethylene dioxythiophene), PANI and PEDOT, by 2-3 orders of magnitude, as reported in the March 30 issue of the Proceedings of the National Academy of Sciences (PNAS).
When synthesized as aqueous dispersions in the presence of a nonconducting polyelectrolyte, PANI and PEDOT are easily processed into the complex patterns needed for electrodes and circuits, but their conductivity is poor. Simply exposing these polymers to dichloroacetic acid (DCA) after patterning generates the enormous conductivity enhancement; detailed analysis revealed that DCA operates by dissociating the complexes formed between the polyelectrolyte and the conducting polymer.
These enhanced-conductivity polymers are attractive as robust replacements for the indium-tin oxide electrodes currently used in flat-panel displays and organic solar cells; solar cells using treated PEDOT as the anode showed efficiencies greater than 2%, with high current densities.
For more information, see the news story posted on the Princeton University homepage, or the PNAS research article, “Directly Patternable, Highly Conducting Polymers for Broad Applications in Organic Electronics”.