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Multiparticle Exciton Ionization in Shallow Doped Carbon Nanotubes
Jay D Sau1, Jared J Crochet, Stephen K Doorn
1†Department of Physics, Harvard University, Cambridge, Massachusetts, United States.
The Journal of Physical Chemistry Letters
|August 21, 2015
Summary
Shallow hole doping in carbon nanotubes causes excitons to ionize into electron-hole pairs. This process, dependent on chirality, enhances exciton decay and leads to fluorescence quenching at higher dopant densities.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanotechnology
Background:
- Semiconducting carbon nanotubes (CNTs) exhibit unique electronic properties.
- Exciton behavior in CNTs is crucial for their optoelectronic applications.
- Valley degeneracy in small-diameter CNTs presents opportunities for novel phenomena.
Purpose of the Study:
- To investigate the effect of shallow hole doping on excitons in small-diameter semiconducting CNTs.
- To elucidate the mechanism of exciton ionization and its dependence on dopant density and chirality.
- To explain the observed fluorescence quenching in doped CNTs.
Main Methods:
- Theoretical prediction of resonant ionization of excitons.
- Modeling the dependence of exciton decay rate on dopant density.
- Analysis of multiparticle exciton ionization for fluorescence quenching.
Main Results:
- Shallow hole doping induces resonant ionization of excitons into free electron-hole pairs.
- Exciton decay efficiency scales with the square of the dopant density.
- Multiparticle exciton ionization explains delocalized fluorescence quenching.
Conclusions:
- Resonant exciton ionization is a key mechanism in doped CNTs.
- Chirality plays a critical role in this doping-induced phenomenon.
- Understanding this mechanism is vital for designing CNT-based electronic and optoelectronic devices.
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