Bright Fluorescence from Individual Single-Walled Carbon Nanotubes

Single-walled carbon nanotubes (SWNTs) have unique photophysical, properties but low fluorescence efficiency. We have found significant increases in the fluorescence efficiency of individual DNA wrapped SWNTs upon addition of reducing agents, including dithiothreitol, Trolox, and beta-mercaptoethanol. Brightening was reversible, upon removal of the reducing molecules, suggesting that a transient eduction of defect sites on the SWNT sidewall causes the effect. The resiilts imply that SWNTs are intrinsically bright emitters and that their poor emission arises from defective nanotubes.