Synthesis, characteristics, and field emission of doped and de-doped polypyrrole, polyaniline, poly(3,4-ethylenedioxythiophene) nanotubes and nanowires

Doped and de-doped nanotubes and nanowires of polypyrrole, polyaniline, and poly(3,4-ethylenedioxythiophene) were synthesized by the electrochemical polymerization method, using Al₂O₃ nanoporous templates. The electrical and optical properties of the nanotubes and nanowires were controlled through various synthetic conditions, such as doping level, dopant, and template-dissolving solvents. The diameters and wall thicknesses of the nanotubes were 100-200 nm and 10-30 nm, respectively. To determine the electrical and optical properties of the nano-systems, I-V characteristic curves with gate bias, dc conductivity, and UV-vis spectra were measured. We observed that the nano-systems were transformed from a conducting state to a semiconducting (or insulating) state through the process of de-doping using the template-dissolving solvents. Possible applications of these nanotubes and nanowires in the construction of nanotip emitters in field emission displays and polymer-based transistors are presented.