Implementation of Flexible Embedded Nanowire Electrodes in Organic Light-Emitting Diodes

The implementation of silver nanowires (NWs) as flexible transparent electrodes (FTEs) in solution-processed organic light-emitting diodes (OLEDs) still faces two major challenges: the high roughness of NW films and heat sensitivity of the most commonly used transparent substrate poly(ethylene terephthalate) (PET). A solution-based, roll-to-roll, and sheet-to-sheet scalable process to create indium tin oxide (ITO)-free FTEs is reported. This FTE is realized by spraying NWs on PET, without the necessity of postdeposition heat treatment. To overcome the roughness limitation, NW films are reverse transfer embedded on another PET substrate. As a result, the FTE shows a low roughness, as well as high mechanical, thermal, organic-solvent, and plasma stability. This developed FTE shows comparable transmittance with ITO but lower sheet resistance and higher mechanical stability. The FTE is implemented in a solution-processed OLED with PDY-132 (Super Yellow) as the emissive layer. In contrast to many other works in this field, a ZnO-nanoparticle electron-injection layer is used on the NWs instead of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) or other organic hole injectors. The use of ZnO nanoparticles instead of organic layers yields many advantages in terms of process and device stability. The resulting devices show greater flexibility, conductivity, and luminance than PET/ITO reference devices, while having the same power efficacy.Peer Reviewe