Raman Radial Mode Revealed from Curved Graphene

Lee, Jae Kap; Hembram, K. P. S. S.; Park, Yeseul; Lee, Sang Gil; Kim, Jin Gyu; Lee, Wooyoung; Moon, Dong Ju

doi:10.1021/acs.jpclett.7b01220

Cited by 9 publications

(11 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…19 Lee et al have shown that low-energy Raman signals of graphene structures (interpreted as RBM) are due to the radial mode (RM) formed by end curvatures of graphene of ∼2.2 nm diameter. 20 The RM model, where eigenvectors head for the center of the curvature of graphene structures, covers the RBM hypothesis of SWNTs. This indicates that the low-energy Raman signals are not unique to SWNTs and thus cannot be evidence for the tubular graphene structures.…”

Section: ■ Introductionmentioning

confidence: 99%

“…However, the low-energy Raman signals have been reported from graphene structures − as well as thin nanographite comprising a few layers of graphene . Lee et al have shown that low-energy Raman signals of graphene structures (interpreted as RBM) are due to the radial mode (RM) formed by end curvatures of graphene of ∼2.2 nm diameter . The RM model, where eigenvectors head for the center of the curvature of graphene structures, covers the RBM hypothesis of SWNTs.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Reinterpretation of Single-Wall Carbon Nanotubes by Raman Spectroscopy

et al. 2019

Self Cite

View full text Add to dashboard Cite

Raman spectra of single-wall carbon nanotubes (SWNTs) exhibit a unique radial breathing mode (RBM) band (∼100−300 cm −1 ) and a G − peak (∼1570 cm −1 ), along with a D band (∼1350 cm −1 ). We show that the typical Raman signals for SWNTs are the signature of their helical structure determined using density functional theory simulation and structural analysis for hydrogenated and dehydrogenated SWNT samples. We demonstrate that the G − mode at ∼1570 cm −1 is unique to opened tubular graphene structures of ∼2 nm diameter. We also demonstrate that the D mode of ∼1350 cm −1 is originated from edge defects of opened SWNTs, revealing strong eigenvectors, which is absent in concentric tubes. We also report a radial−tangential mode (RTM) for concentric and opened SWNTs, which appears following RBM. We also interpret the low-energy Raman signal, reported as an RBM band, to be convolution of "localized RBM" (∼170 cm −1 ) and RTM (∼190 cm −1 ) for helical SWNTs. We also show that the analysis of the Raman spectra of SWNTs is consistent with general understanding on Raman analysis of carbon materials.

show abstract

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reinterpretation of Single-Wall Carbon Nanotubes by Raman Spectroscopy

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…On the other hand, the revelation of the edge of the sheet (Fig. 2b) is due to the nature of the 2D structures where the ends appear as curved (Lee et al, 2017).…”

Section: Structure Analysis Of H-bn Plateletsmentioning

confidence: 99%

AB-stacked nanosheet-based hexagonal boron nitride

Lee

Kim

Hembram

et al. 2021

Acta Crystallogr Sect B

Self Cite

View full text Add to dashboard Cite

Hexagonal boron nitride (h-BN) has been generally interpreted as having an AA stacking sequence. Evidence is presented in this article indicating that typical commercial h-BN platelets (∼10–500 nm in thickness) exhibit stacks of parallel nanosheets (∼10 nm in thickness) predominantly in the AB sequence. The AB-stacked nanosheet occurs as a metastable phase of h-BN resulting from the preferred texture and lateral growth of armchair (110) planes. It appears as an independent nanosheet or unit for h-BN platelets. The analysis is supported by simulation of thin AB films (2–20 layers), which explains the unique X-ray diffraction pattern of h-BN. With this analysis and the role of pressure in commercial high-pressure high-temperature sintering (driving nucleation and parallelizing the in-plane crystalline growth of the nuclei), a growth mechanism is proposed for 2D h-BN (on a substrate) as `substrate-induced 2D growth', where the substrate plays the role of pressure.

show abstract

“…Thus some researchers name the low-frequency Raman signals of the graphene structures as RBM-like without further explanation 11 , 15 or layer breathing modes of bilayer graphene 13 , 14 . Lee et al have shown that the low-frequency Raman signals of graphene structures (100–500 cm −1 ) are due to the radial mode (RM) formed by end nano-curvatures of mono- or bilayer graphene 16 . Indeed, the limit of the low-frequency Raman signals of SWNTs has been inconsistently reported to be ~ 200, ~ 250, ~ 300, ~ 350, and ~ 400 cm −1 , while some well-defined Raman spectra of SWNTs reveal many ripple-like peaks 1 – 5 , 17 – 27 distributed from ~ 200 cm −1 to ~ 1300 cm −1 .…”

Section: Introductionmentioning

confidence: 99%

“…This is due to the general understanding that it originated with synchronous radial vibration of the carbon atoms 2,3 in tubular graphene to be correlated with their diameters, affecting, in turn, their chirality 7 . The RBM mostly appears as a band comprising multiple peaks, and this band signal has been attributed to the presence of plural SWNTs with different diameters to be ~ 0.5-2 nm for 100-300 cm −1 from the equation, ω RBM (cm −1 ) = ~ 248/d where d is diameters of SWNTs 3-5 .The low-frequency Raman signals have also been observed from graphene (or nano-graphitic) structures [8][9][10][11][12][13][14][15][16] . This is unexpected because they are considered unique to SWNTs, i.e., tubular graphene.…”

mentioning

confidence: 99%

Radial-tangential mode of single-wall carbon nanotubes manifested by Landau regulation: reinterpretation of low- and intermediate-frequency Raman signals

Hembram

Kim

Lee

et al. 2023

Sci Rep

Self Cite

View full text Add to dashboard Cite

The low-frequency Raman signals of single-wall carbon nanotubes (SWNTs), appearing in the range of 100–300 cm−1, have been interpreted as radial-breathing mode (RBM) comprising pure radial Eigenvectors. Here, we report that most of the low-frequency and intermediate-frequency signals of SWNTs are radial-tangential modes (RTMs) coexisting radial and tangential Eigenvectors, while only the first peak at the low-frequency side is the RBM. Density functional theory simulation for SWNTs of ~ 2 nm in diameter shows that dozens of RTMs exhibit following the RBM (~ 150 cm−1) up to G-mode (~ 1592 cm−1) in order with Landau regulation. We specify the RBM and the RTM on Raman spectra obtained from SWNTs, where both appear as prominent peaks between 149 and 170 cm−1 and ripple-like peaks between 166 and 1440 cm−1, respectively. We report that the RTMs have been regarded as RBM (~ 300 cm−1) and ambiguously named as intermediate-frequency mode (300–1300 cm−1) without assignment. The RTMs gradually interlink the RBM and the G-mode resulting in the symmetric Raman spectra in intensity. We reveal high-resolution transmission microscope evidence for a helical structure of SWNTs, informing the typical diameter of commercial SWNTs to be 1.4–2 nm.

show abstract

Raman Radial Mode Revealed from Curved Graphene

Cited by 9 publications

References 40 publications

Reinterpretation of Single-Wall Carbon Nanotubes by Raman Spectroscopy

Reinterpretation of Single-Wall Carbon Nanotubes by Raman Spectroscopy

AB-stacked nanosheet-based hexagonal boron nitride

Radial-tangential mode of single-wall carbon nanotubes manifested by Landau regulation: reinterpretation of low- and intermediate-frequency Raman signals

Contact Info

Product

Resources

About