Complete structural characterization of single carbon nanotubes by Rayleigh scattering circular dichroism

Abstract

The accurate characterization of the chiral indices (n,m) of carbon nanotubes has greatly facilitated fundamental investigations and practical applications ranging from electronic circuits and quantum emission to biological detection 1-4 . To meet the growing miniaturizationdriven demand, handedness, the key structural quantity associated with mirror symmetry breaking, needs to be identified both accurately and efficiently 5-7 . To date, optical spectroscopic techniques with unprecedented high-throughput and noninvasive characteristics have achieved great success in identifying chiral indices even at the single-tube level 8-13 . However, none of these optical methods are capable of handedness characterization for single nanotubes due to their extremely weak chiroptical signals (~10 -7 ) compared to the excitation light 14,15 . Here, we demonstrate the complete structure identification of single nanotubes in terms of both chiral indices and handedness by Rayleigh scattering circular dichroism. The success originates from the background-free feature of Rayleigh scattering collected at an oblique angle, which enhances the chiroptical signal from nanotubes by three to four orders of magnitude compared to that using conventional absorption circular dichroism. We measured a total of 30 single-walled carbon nanotubes (including both semiconducting and metallic nanotubes) and found that their absolute chiroptical signals show an obvious structure dependence, which can be qualitatively understood through tightbinding calculations. Our strategy not only opens up exciting opportunities for unlocking the sophisticated functionality of nanotubes but also provides a new platform for chiral discrimination and chiral device exploration at the level of individual nanomaterials.

Recent Advances in Structure Separation of Single‐Wall Carbon Nanotubes and Their Application in Optics, Electronics, and Optoelectronics

“…h) Reproduced with permission. [ 402 ] Copyright 2021, Nature Publishing Group. i) Optical conductivities for the defect‐free region and three types of defects in a (9,2) SWCNT suspended between TEM grid.…”

“…[ 399,400 ] In most recent researches, STM was also employed to identify the chirality or handedness of SWCNTs. [ 401,402 ] In addition to atomically resolved observation, the STM technique can be used to further reveal the electronic structures (DOS) of SWCNTs by measuring the I – V curve. [ 397,398,403 ] Although there is an error of 50–100 mV, [ 397 ] the STM technique has been demonstrated to be an effective approach for the experimental determination of the band structures of SWCNTs.…”

“…In fact, to improve the characterization accuracy, some new characterization techniques based on the combination of spectroscopy and microscopy, have been developed. [ 402,413–417 ] For example, Kappes et al combined AFM with the PL microscopy to investigate the topographical and spectroscopic information of individual SWCNTs on sapphire. [ 414 ] Similar technique was used for the chirality assignment and purity evaluation of SWCNTs by Weisman et al, [ 415 ] but one by one measurement is required.…”

Interlayer Interactions in 1D Van der Waals Moiré Superlattices

“…This extra degree of freedom in 1D moiré superlattices should be considered and identified in the future experiments to fully resolve the interlayer interactions of 1D moiré superlattices. [ 182,183 ]…”

“…This extra degree of freedom in 1D moiré superlattices should be considered and identified in the future experiments to fully resolve the interlayer interactions of 1D moiré superlattices. [182,183] The study of 1D vdW moiré superlattices is in its early stage. There are a lot of exciting phenomena to be demonstrated, such as the evidence and signs of moiré flat bands and correlated physics.…”