Photoluminescence Dynamics Defined by Exciton Trapping Potential of Coupled Defect States in DNA-Functionalized Carbon Nanotubes

Journal Article · Mon Jan 04 00:00:00 EST 2021 · ACS Nano

DOI:https://doi.org/10.1021/acsnano.0c07544· OSTI ID:1774460

Zheng, Yu  ^[1]; Weight, Braden Michael  ^[1]; Jones, Andrew Crandall  ^[1]; Chandrasekaran, Vigneshwaran  ^[1]; Gifford, Brendan Joel  ^[2]; Tretiak, Sergei  ^[1]; Doorn, Stephen K.  ^[1]; Htoon, Han  ^[1]

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2. LosLos Alamos National Lab. (LANL), Los Alamos, NM (United States)

Chemical reactions between semiconducting single-wall carbon nanotubes (SWCNTs) and single-stranded DNA (ssDNA) achieve spatially patterned covalent functionalization sites and create coupled fluorescent quantum defects on the nanotube surface, tailoring SWCNT photophysics for applications such as single-photon emitters in quantum information technologies. The evaluation of relaxation dynamics of photoluminescence (PL) from those coupled quantum defects is essential for understanding the nanotube electronic structure and beneficial to the design of quantum light emitters. Here, we measured the PL decay for ssDNA-functionalized SWCNTs as a function of the guanine content of the ssDNA oligo that dictates the red-shifting of their PL emission peaks relative to the band-edge exciton. We then correlate the observed dependence of PL decay dynamics on energy red-shifts to the exciton potential energy landscape, which is modeled using first-principles approaches based upon the morphology of ssDNA-altered SWCNTs obtained by atomic force microscopy (AFM) imaging. In this work, our simulations illustrate that the multiple guanine defects introduced within a single ssDNA strand strongly interact to create a deep exciton trapping well, acting as a single hybrid trap. The emission decay from the distinctive trapping potential landscape is found to be biexponential for ssDNA-modified SWCNTs. We attributed the fast time component of the biexponential PL decay to the redistribution of exciton population among the lowest energy bright states and a manifold of dark states emerging from the coupling of multiple guanine defects. The long lifetime component in the biexponential decay, on the other hand, is attributed to the redistribution of exciton population among different exciton trapping sites that arise from the binding of multiple ssDNA strands along the nanotube axis. AFM measurements indicate that those trapping sites are separated on average by ~8 nm along the nanotube axis.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Center for Integrated Nanotechnologies (CINT)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 1774460
• Report Number(s): LA-UR-20-28255
• Journal Information: ACS Nano, Vol. 15, Issue 1; ISSN 1936-0851
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
material science
photoluminescence relaxation
exciton localization
patterned quantum defects
coupled trapping potential wells
J-aggregates
exciton hopping process