NOVELTY - An aqueous dispersion comprises a polythiophene and at least one colloid-forming polymeric acid.    USE - The dispersion is useful as buffer layers in organic electronic devices, e.g. organic light omitting diode display, a photoconductive cell, a photodetector, photoresistors, phototube, photoswitch, photovoltaic cell, solar cell, or photo transistor; and in combination with conductive fillers, such as metal nanowires or carbon nanotubes, in applications such as drain, source, or gate electrodes in thin film field effect transistors.    ADVANTAGE - The use of a polymeric acid that is not water soluble in preparation of an aqueous dispersion of the polythiophenes or poly(dioxythiophenes) yields a composition with superior electrical properties. The electrically conductive minute particles are stable in the aqueous medium without forming a separate phase over long period of time before a use. The dispersion does not re-disperse once dried into films.    DETAILED DESCRIPTION - An aqueous dispersion comprises a polythiophene and at least one colloid-forming polymeric acid. The polythiophene has repeating units with the structure (I).R2, R2'=H, alkyl, alkenyl, alkoxy, alkanoyl, alkylthio, aryloxy, alkylthioalkyl, alkylaryl, arylalkyl, amino, alkylamino, dialkylamino, aryl, alkylsulfinyl, alkoxyalkyl, alkylsulfonyl, arylthio, arylsulfinyl, alkoxycarbonyl, arylsulfonyl, acrylic acid, phosphoric acid, phosphonic acid, halogen, nitro, cyano, hydroxyl, epoxy, silane, siloxane, alcohol, benzyl, carboxylate, ether, ether carboxylate, amidosulfonate, ether sulfonate, or urethane.    Provided that both R groups together may form an alkylene or alkenylene chain completing 3, 4, 5, 6, or 7-membered aromatic or alicyclic ring optionally including divalent nitrogen, sulfur or oxygen atoms and may be substituted with R3 group(s).    R3=H, alkyl, alkenyl, aryl, alkanoyl, alkylthioalkyl, alkylaryl, arylalkyl, amino, epoxy, silane, siloxane, alcohol, amidosulfonate, benzyl, carboxylate, ether, ether carboxylate, ether sulfonate, or urethane.    An INDEPENDENT CLAIM is also included for an organic electronic device (i.e. organic light omitting diode display, a photoconductive cell, a photodetector, photoresistors, phototube, photoswitch, photovoltaic cell, solar cell, or photo transistor) having at least one buffer layer (120) comprising the inventive composition.    DESCRIPTION OF DRAWING(S) - The figure is a cross-sectional view of an electronic device.    Anode layer (110)    Buffer layer (120)    Electroluminescent layer (130)    Electron-injection/transport layer (140)    Cathode layer (150)