Structural, electronic, optical and vibrational properties of nanoscale carbons and nanowires: a colloquial review

Abstract

This review addresses the field of nanoscience as viewed through the lens of the scientific career of Peter Eklund, thus with a special focus on nanocarbons and nanowires. Peter brought to his research an intense focus, imagination, tenacity, breadth and ingenuity rarely seen in modern science. His goal was to capture the essential physics of natural phenomena. This attitude also guides our writing: we focus on basic principles, without sacrificing accuracy, while hoping to convey an enthusiasm for the science commensurate with Peter's. The term 'colloquial review' is intended to capture this style of presentation. The diverse phenomena of condensed matter physics involve electrons, phonons and the structures within which excitations reside. The 'nano' regime presents particularly interesting and challenging science. Finite size effects play a key role, exemplified by the discrete electronic and phonon spectra of C(60) and other fullerenes. The beauty of such molecules (as well as nanotubes and graphene) is reflected by the theoretical principles that govern their behavior. As to the challenge, 'nano' requires special care in materials preparation and treatment, since the surface-to-volume ratio is so high; they also often present difficulties of acquiring an experimental signal, since the samples can be quite small. All of the atoms participate in the various phenomena, without any genuinely 'bulk' properties. Peter was a master of overcoming such challenges. The primary activity of Eklund's research was to measure and understand the vibrations of atoms in carbon materials. Raman spectroscopy was very dear to Peter. He published several papers on the theory of phonons (Eklund et al 1995a Carbon 33 959-72, Eklund et al 1995b Thin Solid Films 257 211-32, Eklund et al 1992 J. Phys. Chem. Solids 53 1391-413, Dresselhaus and Eklund 2000 Adv. Phys. 49 705-814) and many more papers on measuring phonons (Pimenta et al 1998b Phys. Rev. B 58 16016-9, Rao et al 1997a Nature 338 257-9, Rao et al 1997b Phys. Rev. B 55 4766-73, Rao et al 1997c Science 275 187-91, Rao et al 1998 Thin Solid Films 331 141-7). His careful sample treatment and detailed Raman analysis contributed greatly to the elucidation of photochemical polymerization of solid C(60) (Rao et al 1993b Science 259 955-7). He developed Raman spectroscopy as a standard tool for gauging the diameter of a single-walled carbon nanotube (Bandow et al 1998 Phys. Rev. Lett. 80 3779-82), distinguishing metallic versus semiconducting single-walled carbon nanotubes, (Pimenta et al 1998a J. Mater. Res. 13 2396-404) and measuring the number of graphene layers in a peeled flake of graphite (Gupta et al 2006 Nano Lett. 6 2667-73). For these and other ground breaking contributions to carbon science he received the Graffin Lecture award from the American Carbon Society in 2005, and the Japan Carbon Prize in 2008. As a material, graphite has come full circle. The 1970s renaissance in the science of graphite intercalation compounds paved the way for a later explosion in nanocarbon re...

Fluorescence from graphene oxide and the influence of ionic, π–π interactions and heterointerfaces: electron or energy transfer dynamics

“…Graphene (Gra) in its pure form has attracted a lot of research attention. 1,2 Notably its oxidized form, graphene oxide (GO), has also sought equal importance [2][3][4][5][6] because of its application potential in electronic devices, [7][8][9] biomedical and environmental remedies. Initially, in 1860 Brodie 10 produced graphite oxide (presently known as graphene oxide) for the first time and later Staudenmeier 11 in 1898 and Hummers et al 12 in 1958 have synthesized the same.…”

“…In the present perspective we have avoided the GO-synthesis details, however, please refer to an earlier article in which various chemical methods are discussed in the view point of large-area thin-film electronics and optoelectronics. 5 Structural, electronic, optical and vibrational properties of nanoscale carbons and nanowires are discussed in a review by Cole et al 4 Graphenebased nanomaterials in optical and optoelectronic applications were reviewed by Chang et al 54 Given the background and disagreements in interpreting the emission mechanism necessitates its understanding of the current state of art. Hence in this perspective we critically discuss various results from the literature in an attempt to provide a clear insight into those explanations.…”

Effects of Surface Curvature and Surface Strength on Argon Adsorption in Carbon Nanotubes at Temperatures below the Triple Point

“…The argon adsorption isotherms in a defective SWCNT (5% defects) are presented in Figure 12(b). The inset of Figure 12(b) shows the structure of the vacancy defects, which is one of the typical defects observed in carbon nanotubes (Cole et al 2010). In this case, the 2D critical temperature is reduced from 65 K to 58 K, suggesting the significant influence of defects in the model.…”

“…This conclusion is consistent with the results of methane adsorption in a bundle of single-walled carbon nanotubes (Albesa et al 2010) and of argon adsorption on the surface of a single-walled carbon nanotube (Wang et al 2010). On the other hand, due to defects in the nanostructures, the nanotubes used experimentally (Cole et al 2010) might not have been as homogeneous as the graphite model used in the simulation. This could have resulted in a weaker carbon nanotube surface with corrugation effects being induced; if so, the 2D critical temperature of the first layer would be less than 66 K. This suggestion is explored further in Section 3.3 below.…”

Effects of synthesis conditions on the structural features and methane adsorption properties of single-walled carbon nanohorns prepared by a gas-injected arc-in-water method

“…[5][6][7][8][9][10][11][12] As a result, the synthesis and applications of these materials have been highly developed. [13][14][15][16][17][18][19] Among these materials, SWCNHs are considered as promising materials for many applications such as drug delivery, 20 energy applications, [21][22][23] gas adsorptions, [23][24][25][26] etc.…”