||(Flexible Organic Light Emitting Diode；FOLED) is a popular technology in display area. It has some advantages such as self-luminous, wide viewing angle, and flexible. Currently, the most widely used transparent electrode was indium tin oxide (ITO) in OLEDs. If we want to fabrication FOLED, ITO is unsuitable as the electrode in FOLEDs. So we use the polymer material such as PEDOT:PSS to replace ITO, but not higher conductivity than ITO ; thus, it is important to enhance conductivity of PEDOT:PSS.|
In this study, we enhance the conductivity of PEDOT:PSS for ITO-free organic light emitting diodes. The conductive PEDOT chains has having a hydrophobic and insulation PSS chains having a hydrophilic. The conductivity is poor of PEDOT:PSS, because the two chains has the Coulomb each other attraction, so the carrier has limitation to transport. We use the 20M formic acid to treat the PEDOT:PSS by dipping process, we found the conductive enhance from 0.3 (S/cm) to 1223 (S/cm) with proportion of PEDOT and PSS decrease. The film were investigated with UV-vis、AC-2、AFM, we use the XPS to analyze the proportion of PEDOT:PSS, and then use the RIE to treat the film that has the pattern. When the heat-treatment PEDOT:PSS anode device at the luminance of 1000 cd/m^2, the performance of the current efficiency are 13.40 cd/A , power efficiency are 4.98 lm/W and EQE are 6.68%.