Fabrication of Flexible ITO-Free OLED Using Vapor-Treated PEDOT:PSS Thin Film As Anode

The present research purports to have obtained highly conductive poly(3,4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT:PSS) films as transparent anodes for organic light emitting diodes (OLEDs) using the vapors of ethanol, ethylene glycol, sulfuric acid, and acetone. Polar vapor exhibited the capability to decrease the sheet resistance from 130 kΩ/sq to 97 Ω/sq through modifying the surface of PEDOT:PSS film treated by ethanol. The conductivity enhancement mechanism has been explained by vapor polarity of the solvent. Root mean square roughness of the films was altered from 1.80 to 1.34 nm after being treated with ethanol. The transmittance indices of all the treated films have been more than 85% in the visible spectral range. Polar vapor-treated PEDOT:PSS films with low sheet resistance and high optical transmittance were applied as an anode in the OLEDs. Flexible indium tin oxide-free OLED manufactured based on PEDOT:PSS film treated with ethanol vapor displayed the highest luminance intensity of 564 cd/m
²
.