Control of the Surface Composition of a Conducting‐Polymer Complex Film to Tune the Work Function

Abstract Control of surface composition of a hole‐injecting conducting polymer complex, poly(3,4‐ethylenedioxy thiophene) (PEDOT) doped with a polystyrene sulfonate (PSS) has been conducted in the spin‐cast films. We found that the work function of the polymeric complex films formed via single spin‐coating can be greatly increased up to 5.44 eV by increasing the surface concentration of the PSS dopant. As a result, we improved the device efficiency and the lifetime of green emitting polymer light‐emitting diodes (PLEDs). This implies that the PSS surface layer of the films spin‐cast from the conducting polymer complexes plays a key role in making high performance PLEDs.