Electrically conducting organic polymer/nanoparticle composites and methods for use thereof
View Patent ↗Compositions are provided comprising aqueous dispersions of electrically conducting organic polymers and a plurality of nanoparticles. Films cast from invention compositions are useful as buffer layers in electroluminescent devices, such as organic light emitting diodes (OLEDs) and electrodes for thin film field effect transistors. Buffer layers containing nanoparticles have a much lower conductivity than buffer layers without nanoparticles. In addition, when incorporated into an electroluminescent (EL) device, buffer layers according to the invention contribute to higher stress life of the EL device.
1. A composition comprising an aqueous dispersion of an electrically conductive organic polymer and a plurality of nanoparticles wherein said electrically conductive organic polymer is selected from polyaniline with poly(2-acrylamido-2-methyl-1-propanesulfonic acid) as the counterion (Pani/PAAMPSA) and poly(ethylenedioxythiophene) with poly(styrenesulfonic acid) as the counterion (PEDT/PSS) and wherein nanoparticles are selected from the group consisting of inorganic nanoparticles, and wherein the composition is capable of forming a buffer layer having a conductivity of less than 1×10 −5 S/cm.
2. A composition according to claim 1 , wherein said inorganic nanoparticles are selected from silica, alumina and electrically conductive metal oxides.
3. A composition according to claim 1 , wherein said nanoparticles have a particle size less than about 500 nm.
4. A composition according to claim 1 , wherein said nanoparticles have a particle size less than about 250 nm.
5. A composition according to claim 1 , wherein said nanoparticles have a particle size less than about 50 nm.
6. A composition according to claim 2 , wherein the weight ratio of silica:electrically conductive polymer is about 4:1.