Oxygen Doping Modifies Near-Infrared Band Gaps in Fluorescent Single-Walled Carbon Nanotubes

Abstract

Better Imaging When Separated A fluorescent probe works better if its absorption and emission wavelengths are well separated; otherwise, the probe tends to reabsorb its own emission. Ghosh et al. (p. 1656 , published online 25 November) found that oxygen doping of semiconducting single-wall carbon nanotubes (SWCNTs) improved the characteristics of these materials as imaging probes in the near-infrared. Exposure of SWCNTs to ozone and then to visible light caused the emission wavelength to be 10 to 15% longer than the absorption wavelength. They imaged these probes and untreated SWCNTs in cultured human cells and found an ∼20-fold improvement in contrast.