Semiconductive Polymer-Doped PEDOT with High Work Function, Conductivity, Reversible Dispersion, and Application in Organic Solar Cells

Upon consideration of intrinsic insulated poly(styrenesulfonate) in conductive PEDOT:PSS poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), we investigated the structure homogeneity of PEDOT:PSS on its hole injection/extraction property in our previous work. For an enhancement of the structural homogeneity of PEDOT derivatives, conductive dispersant poly(diphenylamine-4-sulfonic acid) (PDAS) was applied to efficiently dope PEDOT to obtain a new water-dispersed conductive polymer PEDOT:PDAS. Compared with traditional PEDOT:PSS, PEDOT:PDAS showed much higher work function (5.38 eV), lower acidity (pH of about 7), outstanding film formation, and prospective structural homogeneity. It is worth mentioning that the conductivity of PEDOT:PDAS (0.135 S cm –1 ) was an order of magnitude higher than that of PEDOT:PSS-4083 (0.02 S cm –1 ) although PEDOT:PDAS exhibited very low PEDOT content. Organic solar cells using PEDOT:PDAS as the extraction layer showed comparable performance with the PEDOT:PSS control devices. More interestingly, PEDOT:PDAS powder can be redispersed several times because of the weak aggregation among PDAS backbones, and our result provides a practically feasible approach for the efficient storage and transportation of PEDOT ink for future industrial applications such as antistatic coating.