High 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 high resistance PEDT/PSS buffer layers. In accordance
with a further embodiment, methods have been developed for decreasing the conductivity
of a PEDT/PSS layer cast from aqueous solution onto a substrate, by adding a cyclic
ether co-solvent to the aqueous solution of PEDT/PSS prior to casting. In one embodiment,
there are provided methods for decreasing the inherent conductivity of a PEDT/PSS
layer cast onto a substrate so that this material can be used as an intermediate
buffer layer in red, green, blue organic light emitting diodes (RGB OLEDs).