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Reversible surface oxidation and efficient luminescence quenching in semiconductor single-wall carbon nanotubes
Gordana Dukovic1, Brian E White, Zhiyong Zhou
1Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, USA.
Journal of the American Chemical Society
|November 19, 2004
Summary
We found that single-wall carbon nanotubes (SWNTs) can be reversibly oxidized. The resulting oxide is a 1,4-endoperoxide that, at low pH, creates a hole in the SWNT, quenching its luminescence.
Area of Science:
- Materials Science
- Chemistry
- Nanotechnology
Background:
- Single-wall carbon nanotubes (SWNTs) exhibit unique optical and electronic properties.
- Understanding their surface chemistry, including oxidation, is crucial for applications.
- Reversible oxidation processes are desirable for tunable nanomaterials.
Purpose of the Study:
- To investigate the reversible oxidation of SWNTs.
- To characterize the structure of the oxidized SWNTs.
- To understand the impact of oxidation on SWNT optical properties.
Main Methods:
- Quantitative analysis of absorption bleaching and luminescence quenching.
- Low pH conditions were employed.
- Density Functional Theory (DFT) structure calculations were utilized.
Main Results:
- SWNT oxidation was found to be reversible.
- The oxide structure was identified as a 1,4-endoperoxide.
- Protonation at low pH created a hydroperoxide carbocation, introducing a hole in the SWNT valence band.
- Nanotube luminescence was highly sensitive to quenching by this hole-doping, while absorption remained robust.
Conclusions:
- The reversible oxidation of SWNTs to a 1,4-endoperoxide has been demonstrated.
- This oxidation process significantly impacts SWNT optoelectronic properties via hole-doping.
- The findings provide insights into SWNT surface chemistry and potential for controlled modification.