Single wall carbon nanotube/poly(3,4-ethylenedioxythiophene) nanocomposite film as a transparent electrode for flexible organic light-emitting diodes

•We prepared SWNT/PEDOT nanocomposite flexible transparent electrodes.•PEDOT was in situ polymerized on a preformed SWNT conducting network.•SWNT network much lowered the surface resistance of the PEDOT film.•Uniform current flowing on the nanocomposite surface was visualized by C-AFM current mapping.•We successfully fabricated a flexible OLED with the nanocomposite anode.

We prepared a flexible transparent electrode comprising a single wall carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWNT/PEDOT) nanocomposite in which the PEDOT matrix was in situ polymerized on the preformed SWNT conducting network. With the aid of the SWNT network, the SWNT/PEDOT nanocomposite film gave a much lower surface resistance (∼160 Ω/□) with a high transmittance (86% at 550 nm), compared with the neat PEDOT film of the same thickness. Current mapping of the nanocomposite film surface by conductive-atomic force microscopy (C-AFM) exhibited that most of SWNTs participate in the conducting network while the PEDOT matrix provides electrical pathways across the separated SWNT chains and enables a smoother, pore-free film with a uniform current flow on the overall surface of the film. When the SWNT/PEDOT nanocomposite film was employed as an anode of Alq3-based flexible organic light-emitting diode (FOLED), the device demonstrated ∼3 times enhanced brightness and ∼1.9 times enhanced current efficiency than the device with the neat PEDOT anode.

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