Electronic composite of sulfonated tetrafluorethylene copolymer with potassium ferricyanide exhibiting room-temperature negative differential resistance

A two-phase composite material was prepared by mixing the polymer Nafion with an electroactive molecule, potassium ferricyanide. The current-voltage characteristic of the material shows a finite conductance about zero bias, indicating a metal-like electrical conduction. The conductance is found to be proportional to the concentration of the potassium ferricyanide molecule and temperature. A conductance peak is present at a low bias voltage, providing a region of negative differential resistance. A peak-to-valley current ratio of 1.8 was obtained with a current density of 30 mu A/cm(2). A conduction mechanism based electron tunneling between the active sites of the molecule is proposed. (c) 2006 American Institute of Physics.