Highly flexible, conductive and transparent PEDOT:PSS/Au/PEDOT:PSS multilayer electrode for optoelectronic devices

• Multilayer polymeric based electrode for flexible optoelectronics is fabricated.
• PEDOT:PSS/Au/PEDOT:PSS electrode is comparable to ITO by sheet resistance.
• Electro-optical properties of the electrode are dependent on the Au film thickness.
• Mechanical stability of the PEDOT:PSS based electrode is superior compared to ITO.

The electrical, optical and bending characteristics of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/Au/PEDOT:PSS deposited on polyethylene terephthalate (PET) substrate were studied as a function of inserted Au film thickness. The results were compared with those of indium-tin-oxide (ITO) and single layer PEDOT: PSS electrodes. It was found that insertion of Au film with optimized thickness between PEDOT:PSS layers improved the sheet resistance in comparison to single PEDOT:PSS film and ITO film. It was demonstrated that PEDOT: PSS(35 nm)/Au(15 nm)//PEDOT: PSS(35 nm) exhibits sheet resistance of 20.9 Ω/sq and maximum optical transmission of 82.6% in the visible region. Moreover, this multilayer electrode showed dramatically improved mechanical stability compared to ITO, when subjected to multiple bends. Its sheet resistance variation was 3.8% after applying 2000 bending cycles at radius of curvature 6 mm in comparison to 6.7% for single PEDOT: PSS film and 11.4% for ITO.