Fluorescence efficiency of individual carbon nanotubes

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Single-walled carbon nanotubes (SWCNTs) are promising nanomaterials with unique optical properties.
• Accurate measurement of SWCNT luminescence efficiency is crucial for their application.
• Previous studies on ensemble SWCNT luminescence may not reflect intrinsic properties.

Purpose of the Study:

• To accurately determine the luminescence efficiency of individual single-walled carbon nanotubes.
• To compare the quantum yield (QY) of individual SWCNTs with that of well-characterized quantum dots.
• To re-evaluate the intrinsic luminescence properties of SWCNTs.

Main Methods:

• Utilized single-particle fluorescence spectroscopy to measure individual SWCNTs.
• Employed single Cadmium Telluride/Zinc Sulfide (CdTe/ZnS) quantum dots with a known fluorescence quantum yield as a reference.
• Compared the fluorescence intensity of individual SWCNTs to that of reference quantum dots.

Main Results:

• Determined the fluorescence quantum yield (QY) of individual SWCNTs to be 3 +/- 1%.
• This measured QY is approximately 100 times greater than previously reported values for SWCNT ensembles.
• Observed a significant discrepancy between individual SWCNT QY and ensemble measurements.

Conclusions:

• The intrinsic luminescence efficiency of single-walled carbon nanotubes is significantly higher than previously estimated from ensemble measurements.
• Defective nanotubes and residual bundling in ensembles likely contribute to the lower observed QY in bulk samples.
• Individual SWCNT measurements provide a more accurate assessment of their photophysical potential for optoelectronic applications.