• organic photovoltaics;
  • carbon nanotubes;
  • density gradient ultracentrifugation;
  • separation;
  • X-ray photoelectron spectroscopy
Thumbnail image of graphical abstract

Single-walled carbon nanotubes (SWNTs) sorted by electronic type are employed as organic photovoltaic device anodes. Metal-enriched SWNT films yield device efficiencies that are fifty times greater than their semiconducting counterparts. Through sheet resistance, UV-vis-NIR optical absorbance, and X-ray photoelectron spectroscopy measurements, the OPV charge blocking layer PEDOT:PSS is found to reverse the original chemical doping of the SWNT films. The relative insensitivity of metallic SWNTs to chemical doping thus explains the improved performance of metal-enriched SWNT films as OPV anodes.