Low roughness silver nanowire flexible transparent electrode by low temperature solution-processing for organic light emitting diodes

Highly smooth, conductive, and uniform flexible transparent composite film is produced by embedding silver nanowires (AgNWs) into polymer without high-temperature annealing. The insert of poly (vinyl alcohol) (PVA) layer enhances the hydrophilicity of the substrate surface and avoids the agglomeration of AgNWs. The thick junctions between nanowires are welded to the same height as a single wire by mechanical pressing, resulting in a great increase of the electrical conductivity and low surface roughness. The sheet resistance of the PVA/AgNW composite film reaches 3 Omega/sq with a transmittance of 83%, and does not show obvious change after tape test and substrate bending, suggesting good adhesion of AgNWs to the substrate and excellent flexibility. The composite film possesses better stability of resisting the chemical corrosion than conventional annealed-AgNW film. The scattering of AgNWs can break the waveguide mode and the total internal reflection, which consequently enhances the out-coupling efficiency in an organic light emitting diode (OLED). Flexible OLED employing the PVA/AgNW composite film as anode on polyethylene naphthalate (PEN) substrate presents a current efficiency improvement of 27% compared to controlled ITO-anode device with same structure, demonstrating its exciting prospect for applications in flexible optoelectronics. (C) 2017 Elsevier B.V. All rights reserved.