Strong and Stable Doping of Carbon Nanotubes and Graphene by MoOx for Transparent Electrodes

MoOx has been used for organic semiconductor doping, but it had been considered an inefficient and/or unstable dopant. We report that MoOx can strongly and stably dope carbon nanotubes and graphene. Thermally annealed MoOx-CNT composites can form durable thin film electrodes with sheet resistances of 100 Omega/sq at 85% transmittance plain and 85 Omega/sq at 83% transmittance with a PEDOT:PSS adlayer. Sheet resistances change less than 10% over 20 days in ambient and less than 2% with overnight heating to 300 degrees C in air. The MoOx can be easily deposited either by thermal evaporation or from solution-based precursors. Excellent stability coupled with high conductivity makes MoOx-CNT composites extremely attractive candidates for practical transparent electrodes.