UC Davis

Recent development of dopant induced solubility control (DISC) patterning of polymer semiconductors has enabled direct-write optical patterning of poly-3-hexylthiophene (P3HT) with diffraction limited resolution. Here, the optical DISC patterning technique to the most simple circuit element, a wire, is applied. Optical patterning of P3HT and P3HT doped with the molecular dopant 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) wires with dimensions of 20–70 nm thickness, 200–900 nm width, and 40 μm length is demonstrated. In addition, optical patterning of wire patterns like “L” bends and “T” junctions without changing the diameter or thickness of the wires at the junctions is demonstrated. The wires themselves show up to 0.034 S cm-1 conductance when sequentially doped. It is also demonstrated that a P3HT nanowire can be doped, de-doped, and re-doped from solution without changing the dimension of the wire. The combined abilities to optically pattern and reversibly dope a polymer semiconductor represents a full suite of patterning steps equivalent to photolithography for inorganic semiconductors.