02711nas a2200289   4500008004100000022001400041245014600055210006900201260007100270300001200341490000600353520162200359653005601981653002102037653001302058653002702071653003502098100001602133700002402149700001402173700001502187700001602202700002402218700003002242700002302272856012602295       2014                        eng d  a1936-085100aSequential electrochemical unzipping of single-walled carbon nanotubes to graphene ribbons revealed by in situ Raman spectroscopy and imaging0 aSequential electrochemical unzipping of singlewalled carbon nano  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJAN  a234-2420 v83 a<p>We report an in situ Raman spectroscopic and microscopic investigation of the electrochemical unzipping of single-walled carbon nanotubes (SWNTs). Observations of the radial breathing modes (RBMs) using Raman spectral mapping reveal that metallic SWNTs are opened up rapidly followed by gradual unzipping of semiconducting SWNTs. Consideration of the resonant Raman scattering theory suggests that two metallic SWNTs with chiralities (10,4) and (12, 0) get unzipped first at a lower electrode potential (036 V) followed by the gradual unzipping of another two metallic tubes, (9, 3) and (10, 1), at a relatively higher potential (1.16 V). The semiconducting SWNTs with chiralities (11, 7) and (12, 5), however, get open up gradually at +/- 1.66 V. A rapid decrease followed by a subsequent gradual decrease in the metallicity of the SWNT ensemble as revealed from a remarkable variation of the peak width of the G band complies well with the variations of RBM. Cyclic voltammetry also gives direct evidence for unzipping in terms of improved capacitance after oxidation followed by more important removal of oxygen functionalities during the reduction step, as reflected in subtle changes of the morphology confirming the formation of graphene nanoribbons. The density functional-based tight binding calculations show additional dependence of chirality and diameter of nanotubes on the epoxide binding energies, which is in agreement with the Raman spectroscopic results and suggests a possible mechanism of unzipping determined by combined effects of the structural characteristics of SWNTs and applied field.</p>10adensity functional-based tight binding calculations10aElectrochemistry10agraphene10aRaman spectral mapping10asingle-walled carbon nanotubes1 aJohn, Robin1 aShinde, Dhanraj, B.1 aLiu, Lili1 aDing, Feng1 aXu, Zhiping1 aVijayan, Cherianath1 aPillai, Vijayamohanan, K.1 aPradeep, Thalappil  uhttps://library.ncl.res.in/content/sequential-electrochemical-unzipping-single-walled-carbon-nanotubes-graphene-ribbons-0