Solvent and Wavelength-Dependent Photoluminescence Relaxation Dynamics of Carbon Nanotube sp3 Defect States

Xiaowei He, Kirill A. Velizhanin, George Bullard, Yusong Bai, Jean-Hubert Olivier, Nicolai F. Hartmann, Brendan J. Gifford, Svetlana V. Kilina, Sergei Tretiak, Han Htoon, Michael J. Therien, Stephen K. Doorn

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Photoluminescent sp3 defect states introduced to single wall carbon nanotubes (SWCNTs) through low-level covalent functionalization create new photophysical behaviors and functionality as a result of defect sites acting as exciton traps. Evaluation of relaxation dynamics in varying dielectric environments can aid in advancing a more complete description of defect-state relaxation pathways and electronic structure. Here, we exploit helical wrapping polymers as a route to suspending (6,5) SWCNTs covalently functionalized with 4-methoxybenzene in solvent systems including H2O, D2O, methanol, dimethyl formamide, tetrahydrofuran, and toluene, spanning a range of dielectric constants from 80 to 3. Defect-state photoluminescence decays were measured as a function of emission wavelength and solvent environment. Emission decays are biexponential, with short lifetime components on the order of 65 ps and long components ranging from around 100 ps to 350 ps. Both short and long decay components increase as emission wavelength increases, while only the long lifetime component shows a solvent dependence. We demonstrate that the wavelength dependence is a consequence of thermal detrapping of defect-state excitons to produce mobile E11 excitons, providing an important mechanism for loss of defect-state population. Deeper trap states (i.e. those emitting at longer wavelengths) result in a decreased rate for thermal loss. The solvent-independent behavior of the short lifetime component is consistent with its assignment as the characteristic time for redistribution of exciton population between bright and dark defect states. The solvent dependence of the long lifetime component is shown to be consistent with relaxation via an electronic to vibrational energy transfer mechanism, in which energy is resonantly lost to solvent vibrations in a complementary mechanism to multi-phonon decay processes.

Original languageEnglish (US)
JournalACS Nano
DOIs
StateAccepted/In press - Apr 18 2018

Fingerprint

Carbon Nanotubes
Carbon nanotubes
Photoluminescence
carbon nanotubes
photoluminescence
Wavelength
Defects
defects
Excitons
wavelengths
excitons
life (durability)
decay
traps
Toluene
Dimethylformamide
tetrahydrofuran
Energy transfer
Electronic structure
Methanol

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

Cite this

Solvent and Wavelength-Dependent Photoluminescence Relaxation Dynamics of Carbon Nanotube sp3 Defect States. / He, Xiaowei; Velizhanin, Kirill A.; Bullard, George; Bai, Yusong; Olivier, Jean-Hubert; Hartmann, Nicolai F.; Gifford, Brendan J.; Kilina, Svetlana V.; Tretiak, Sergei; Htoon, Han; Therien, Michael J.; Doorn, Stephen K.

In: ACS Nano, 18.04.2018.

Research output: Contribution to journalArticle

He, X, Velizhanin, KA, Bullard, G, Bai, Y, Olivier, J-H, Hartmann, NF, Gifford, BJ, Kilina, SV, Tretiak, S, Htoon, H, Therien, MJ & Doorn, SK 2018, 'Solvent and Wavelength-Dependent Photoluminescence Relaxation Dynamics of Carbon Nanotube sp3 Defect States', ACS Nano. https://doi.org/10.1021/acsnano.8b02909
He, Xiaowei ; Velizhanin, Kirill A. ; Bullard, George ; Bai, Yusong ; Olivier, Jean-Hubert ; Hartmann, Nicolai F. ; Gifford, Brendan J. ; Kilina, Svetlana V. ; Tretiak, Sergei ; Htoon, Han ; Therien, Michael J. ; Doorn, Stephen K. / Solvent and Wavelength-Dependent Photoluminescence Relaxation Dynamics of Carbon Nanotube sp3 Defect States. In: ACS Nano. 2018.
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AU - Olivier, Jean-Hubert

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AU - Gifford, Brendan J.

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AU - Therien, Michael J.

AU - Doorn, Stephen K.

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