Electric field induced increase in work function of PEDOT: PSS thin films for efficient optoelectronic device

A method to increase the work function of PEDOT: PSS films used in organic LED displays is proposed. During the drying of PEDOT: PSS drop under an electric field (with positive electrode parallel to the drop surface) gel particles will diffuse towards the surface of the drop (Since gel particles of the polymer which are negatively charged) and migrates against the capillary flow (flow towards the edge forming a ring). This phenomenon can increase the PSS composition on the surface of the dried film by reversing the ring formation, which results in uniform distribution of gel particles throughout the drop. Increase in PSS concentration on the dried film surface, increases the PSS to PEDOT composition ratio. This in turn increases the surface resistance and the work function of the PEDOT:PSS thin films. (author)