Carrier injection from polypyrrole coated gold electrode in pentacene field effect transistors

Carrier injection characteristics of conjugated polymer coated gold (Au) electrode were investigated. Using pentacene field effect transistors (FETs) with Au electrodes covered with polypyrrole (PPy) film deposited electrochemically from an aqueous electrolyte solution of HCl or PTSA (1 M) containing pyrrole monomer, transient microscopic optical second harmonic generation (TRM-SHG) measurements were carried out. Transfer characteristics of the transistors suggested that the injection of holes was assisted by the deposited polymer film improving the hole injection efficiency. The TRM-SHG results well supported the results of the electrical measurements, and we anticipate that polypyrrole could be a potential candidate as an electrode material in polymer electronics.