(161ax) Fabrication of Organic Semiconducting Polymer Nanowires By Doping-Induced Solubility Method

Organic electronics offer a potentially low-cost alternative to inorganic materials in everyday electronics. However, a scalable, inexpensive process to pattern organic semiconductors (OSC) remain an active challenge in the field. In this work, we demonstrate creating sub-micrometer scale organic semiconducting nanowires with various shapes using doping-induced solubility control (DISC) method. DISC is a patterning method based on optically de-doping a polymer and rendering de-doped local regions soluble in a non-selective common solvent for the polymer and the dopant. P3HT/F4TCNQ nanowires were patterned from P3HT/F4TCNQ films using the DISC method. The effect of doping, de-doping and re-doping on the films was investigated using UV-vis-NIR Spectroscopy and Grazing Incident X-ray Diffraction (GIXD). Optical absorption showed no change for doped and re-doped films demonstrating doping reversibility. The dimensions of the nanowires were measured by Atomic Force Microscopy (400 nm width, 50 µm length and 40 nm thickness). Kelvin Probe Force Microscopy (KPM) was applied to determine the conductivity along the nanowire and showed a steady voltage drop, indicating that polymer domain formation does not affect conductivity. Doped, de-doped, and re-doped P3HT films were analyzed with Grazing Incidence Wide Angle X-ray Scattering (GIWAXS). No differences in the structure and packing of the crystallites were observed as a result of sequential doping. Direct-write optics enable successful patterning of “L” and “T” shape nanowires.