US Patent 7317048 Variable resistance poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) for use in electronic devices

Variable resistance PEDT/PSS buffer layers are provided for use in electroluminescent devices such as, e.g., OLEDs. In accordance with another embodiment, there are provided OLEDs comprising variable resistance PEDT/PSS buffer layers. In accordance with a further embodiment, methods have been developed for varying the conductivity of a PEDT/PSS layer cast from aqueous solution onto a substrate, by adding a co-solvent to the aqueous solution of PEDT/PSS prior to casting.