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Title: Optical Effects of Divalent Functionalization of Carbon Nanotubes

Abstract

Covalent functionalization of single-walled carbon nanotubes (SWCNTs) enables tuning of their optical properties through the generation of sp3-hybridized defects with distinct localized morphology. Groups with strong electron-withdrawing abilities result in redshifted emission experimentally. Further redshifts can be generated by groups bound to more than one carbon atom in the SWCNT (“divalent functionalization”). Depending on the type of divalent functionalization, the spectral diversity is reduced compared to their monovalent counterparts. Here we study the effect of divalent functionalization on the exciton localization at the defect site and related redshifts in emission of (6,5) SWCNT through low-temperature spectroscopy measurements and time dependent density functional theory calculations. These effects are characterized for three classes of divalent compounds distinct in the number of atoms in the functional group and bonding pattern to the tube. The bond character of the two carbon atoms proximal to the defect site is found to have a notable impact on the system stability and spectral redshifts. Functionalized systems are stabilized when the hybridization at the SWCNT remains sp2-like due to its ability to form planar bonds to the remaining hexagonal network, while bond character in the functionalized regions affects the redshifts. This is only possible for certain bonding geometriesmore » in divalent species, justifying their decreased spectral diversity. We further show that functionalization at spatially separated sites on the tube can be accompanied by a second chemical adduct, and the configuration of the resulting defect is dictated by bond reactivity following the first addition. This behavior justifies the spectral trends of a class of divalent systems with linker chains or high defect concentration. These results further corroborate that adducts predominantly form chemical bonds only to the neighboring carbons on the SWCNT surface (ortho species) in experimental samples. Our analysis of bond character in the vicinity of the defect sites rationalizes appearance of many spectral features arising from monovalent and divalent defect states of functionalized SWCNTs. As a result, this emerging understanding enables tuning of the emission characteristics through careful control of the defect structure.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2];  [2]; ORCiD logo [1]; ORCiD logo [3]; ORCiD logo [2]; ORCiD logo [1]; ORCiD logo [4]; ORCiD logo [1]; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Univ. of Maryland, College Park, MD (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of Southern California, Los Angeles, CA (United States); U.S. Army Research Lab., Aberdeen, MD (United States)
  4. North Dakota State Univ., Fargo, ND (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR) (SC-21)
OSTI Identifier:
1532715
Report Number(s):
LA-UR-18-31887
Journal ID: ISSN 0897-4756
Grant/Contract Number:  
89233218CNA000001
Resource Type:
Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Name: Chemistry of Materials; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English

Citation Formats

Gifford, Brendan Joel, He, Xiaowei, Kim, Mijin, Kwon, Hyejin, Saha, Avishek, Sifain, Andrew E., Wang, YuHuang, Htoon, Han, Kilina, Svetlana, Doorn, Stephen K., and Tretiak, Sergei. Optical Effects of Divalent Functionalization of Carbon Nanotubes. United States: N. p., 2019. Web. doi:10.1021/acs.chemmater.9b01438.
Gifford, Brendan Joel, He, Xiaowei, Kim, Mijin, Kwon, Hyejin, Saha, Avishek, Sifain, Andrew E., Wang, YuHuang, Htoon, Han, Kilina, Svetlana, Doorn, Stephen K., & Tretiak, Sergei. Optical Effects of Divalent Functionalization of Carbon Nanotubes. United States. doi:10.1021/acs.chemmater.9b01438.
Gifford, Brendan Joel, He, Xiaowei, Kim, Mijin, Kwon, Hyejin, Saha, Avishek, Sifain, Andrew E., Wang, YuHuang, Htoon, Han, Kilina, Svetlana, Doorn, Stephen K., and Tretiak, Sergei. Thu . "Optical Effects of Divalent Functionalization of Carbon Nanotubes". United States. doi:10.1021/acs.chemmater.9b01438.
@article{osti_1532715,
title = {Optical Effects of Divalent Functionalization of Carbon Nanotubes},
author = {Gifford, Brendan Joel and He, Xiaowei and Kim, Mijin and Kwon, Hyejin and Saha, Avishek and Sifain, Andrew E. and Wang, YuHuang and Htoon, Han and Kilina, Svetlana and Doorn, Stephen K. and Tretiak, Sergei},
abstractNote = {Covalent functionalization of single-walled carbon nanotubes (SWCNTs) enables tuning of their optical properties through the generation of sp3-hybridized defects with distinct localized morphology. Groups with strong electron-withdrawing abilities result in redshifted emission experimentally. Further redshifts can be generated by groups bound to more than one carbon atom in the SWCNT (“divalent functionalization”). Depending on the type of divalent functionalization, the spectral diversity is reduced compared to their monovalent counterparts. Here we study the effect of divalent functionalization on the exciton localization at the defect site and related redshifts in emission of (6,5) SWCNT through low-temperature spectroscopy measurements and time dependent density functional theory calculations. These effects are characterized for three classes of divalent compounds distinct in the number of atoms in the functional group and bonding pattern to the tube. The bond character of the two carbon atoms proximal to the defect site is found to have a notable impact on the system stability and spectral redshifts. Functionalized systems are stabilized when the hybridization at the SWCNT remains sp2-like due to its ability to form planar bonds to the remaining hexagonal network, while bond character in the functionalized regions affects the redshifts. This is only possible for certain bonding geometries in divalent species, justifying their decreased spectral diversity. We further show that functionalization at spatially separated sites on the tube can be accompanied by a second chemical adduct, and the configuration of the resulting defect is dictated by bond reactivity following the first addition. This behavior justifies the spectral trends of a class of divalent systems with linker chains or high defect concentration. These results further corroborate that adducts predominantly form chemical bonds only to the neighboring carbons on the SWCNT surface (ortho species) in experimental samples. Our analysis of bond character in the vicinity of the defect sites rationalizes appearance of many spectral features arising from monovalent and divalent defect states of functionalized SWCNTs. As a result, this emerging understanding enables tuning of the emission characteristics through careful control of the defect structure.},
doi = {10.1021/acs.chemmater.9b01438},
journal = {Chemistry of Materials},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {5}
}

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This content will become publicly available on May 16, 2020
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