and Applications of Fullerenes, Carbon Dots, Nanotubes, Graphene, Nanodiamonds, and Combined Superstructures Vasilios Georgakilas,† Jason A. Perman,‡ Jiri Tucek,‡ and Radek Zboril*,‡ †Material Science Department, University of Patras, 26504 Rio Patras, Greece ‡Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University in Olomouc, 17 listopadu 1192/12, 771 46 Olomouc, Czech Republic

Broad family of carbon nanoallotropes: classification, chemistry, and applications of fullerenes, carbon dots, nanotubes, graphene, nanodiamonds, and combined superstructures.

Creating functional electrical circuits using individual or ensemble molecules, often termed as “molecular-scale electronics”, not only meets the increasing technical demands of the miniaturization of traditional Si-based electronic devices, but also provides an ideal window of exploring the intrinsic properties of materials at the molecular level. This Review covers the major advances with the most general applicability and emphasizes new insights into the development of efficient platform methodologies for building reliable molecular electronic devices with desired functionalities through the combination of programmed bottom-up self-assembly and sophisticated top-down device fabrication. First, we summarize a number of different approaches of forming molecular-scale junctions and discuss various experimental techniques for examining these nanoscale circuits in details. We then give a full introduction of characterization techniques and theoretical simulations for molecular electronics. Third, we highlig...

Molecular-Scale Electronics: From Concept to Function

Nanomaterials have emerged as an amazing class of materials that consists of a broad spectrum of examples with at least one dimension in the range of 1 to 100 nm. Exceptionally high surface areas can be achieved through the rational design of nanomaterials. Nanomaterials can be produced with outstanding magnetic, electrical, optical, mechanical, and catalytic properties that are substantially different from their bulk counterparts. The nanomaterial properties can be tuned as desired via precisely controlling the size, shape, synthesis conditions, and appropriate functionalization. This review discusses a brief history of nanomaterials and their use throughout history to trigger advances in nanotechnology development. In particular, we describe and define various terms relating to nanomaterials. Various nanomaterial synthesis methods, including top-down and bottom-up approaches, are discussed. The unique features of nanomaterials are highlighted throughout the review. This review describes advances in nanomaterials, specifically fullerenes, carbon nanotubes, graphene, carbon quantum dots, nanodiamonds, carbon nanohorns, nanoporous materials, core–shell nanoparticles, silicene, antimonene, MXenes, 2D MOF nanosheets, boron nitride nanosheets, layered double hydroxides, and metal-based nanomaterials. Finally, we conclude by discussing challenges and future perspectives relating to nanomaterials.

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Nanomaterials: a review of synthesis methods, properties, recent progress, and challenges

Synthesis of carbon nanotubes by catalytic chemical vapour deposition: A review on carbon sources, catalysts and substrates

Transparent conducting films (TCFs) are a critical component in many personal electronic devices. Transparent and conductive doped metal oxides are widely used in industry due to their excellent optoelectronic properties as well as the mature understanding of their production and handling. However, they are not compatible with future flexible electronics developments where large-scale production will likely involve roll-to-roll manufacturing. Recent studies have shown that carbon nanotubes provide unique chemical, physical, and optoelectronic properties, making them an important alternative to doped metal oxides. This Review provides a comprehensive analysis of carbon nanotube transparent conductive films covering detailed fabrication methods including patterning of the films, chemical doping effects, and hybridization with other materials. There is a focus on optoelectronic properties of the films and potential in applications such as photovoltaics, touch panels, liquid crystal displays, and organic light-emitting diodes in conjunction with a critical analysis of both the merits and shortcomings of carbon nanotube transparent conductive films.

Recent Development of Carbon Nanotube Transparent Conductive Films

Single-walled carbon nanotubes of a single chirality can be produced with an abundance of more than 92 per cent when using tungsten-based bimetallic alloy nanocrystals as catalysts. Single-walled carbon nanotubes (SWNTs) have many outstanding material properties that depend sensitively on their exact structure. This structure–function relationship can be fully exploited only with access to structurally pure SWNTs, but producing just one tube type remains a considerable challenge. Here Feng Yang et al. describe a strategy to realize chirality-specific growth of a single SWNT type using solid tungsten–cobalt alloy nanoparticles as catalysts. The tungsten component ensures high-temperature stability for the catalyst structure and cobalt is an effective catalyst. Optimization of the strategy should boost selectivity further, to deliver structurally pure SWNT samples that may enable wider use and development of these unique materials for practical applications. Carbon nanotubes have many material properties that make them attractive for applications1,2. In the context of nanoelectronics3, interest has focused on single-walled carbon nanotubes4 (SWNTs) because slight changes in tube diameter and wrapping angle, defined by the chirality indices (n, m), will shift their electrical conductivity from one characteristic of a metallic state to one characteristic of a semiconducting state, and will also change the bandgap. However, this structure–function relationship can be fully exploited only with structurally pure SWNTs. Solution-based separation methods5 yield tubes within a narrow structure range, but the ultimate goal of producing just one type of SWNT by controlling its structure during growth has proved to be a considerable challenge over the last two decades6,7,8,9. Such efforts aim to optimize the composition6,10,11,12,13,14,15,16,17 or shape18,19,20,21 of the catalyst particles that are used in the chemical vapour deposition synthesis process to decompose the carbon feedstock and influence SWNT nucleation and growth22,23,24,25. This approach resulted in the highest reported proportion, 55 per cent, of single-chirality SWNTs in an as-grown sample11. Here we show that SWNTs of a single chirality, (12, 6), can be produced directly with an abundance higher than 92 per cent when using tungsten-based bimetallic alloy nanocrystals as catalysts. These, unlike other catalysts used so far, have such high melting points that they maintain their crystalline structure during the chemical vapour deposition process. This feature seems crucial because experiment and simulation both suggest that the highly selective growth of (12, 6) SWNTs is the result of a good structural match between the carbon atom arrangement around the nanotube circumference and the arrangement of the catalytically active atoms in one of the planes of the nanocrystal catalyst. We anticipate that using high-melting-point alloy nanocrystals with optimized structures as catalysts paves the way for total chirality control in SWNT growth and will thus promote the development of SWNT applications.

Chirality-specific growth of single-walled carbon nanotubes on solid alloy catalysts

Graphene oxides (GO) can be considered as polyelectrolytes with surfactant-like characteristics. On one hand, due to the electrical repulsion between the negatively charged ionized edges, GO exhibits great water solubility; on the other hand, its hydrophobic central plane retains the potential of strong π–π interaction with other conjugated sp2 network structures. Therefore, it is expected that GO can serve as an excellent dispersing agent for dispersion of various carbon-based nanomaterials in aqueous phase. Here we report a systematic study of dispersing various carbon-based nanomaterials, including SWNTs, C60, and graphene, by aqueous GO. The GO-dispersed all-carbon nanocomposites are characterized using various spectroscopic methods and electron microscopies, and their stabilities are tested. Compared to other dispersing agents, the GO concentration is much lower than the concentrations of other dispersing agents used when similar contents of carbon-based nanomaterials are dispersed. Involving only si...

Dispersing carbon-based nanomaterials in aqueous phase by graphene oxides.

To explore poly(phenylacetylene) (PPA) deriva- tives as the dispersing agent of single-walled carbon nanotubes (SWNTs), we synthesized a new series of side chain PPAs (denoted as PPA-m, m = 2, 1, 0). The side chains of PPA-m bear a soluble 3,4,5-tris(octyloxy)phenyl moiety at the end, and a biphenyl (m = 2), a phenyl (m = 1), or no phenyl ring (m =0 ) in the middle linked to the PPA main-chain through an ether linkage. All the three PPA-ms can efficiently disperse SWNTs in organic solvents forming stable SWNTs/PPA-m composites. The composites were characterized by microscopy method, absorbance and photoluminescence spectroscopy. Quantitative analysis shows that there is a tendency for PPA-m to preferentially disperse SWNTs with large diameters in tetrahydrofuran and toluene when compared with the normally used surfactant of sodium dodecyl sulfate. The effective interactions between PPA-m and SWNTs should be ascribed to the helical wrapping of the PPA-m backbone on SWNTs and the π−π interactions between the phenyl groups and SWNTs. The long alkyl tails on the side-chains also prevent individual SWNTs from reaggregation. Additionally, the near-infrared (nIR) photoresponsive electrical conductivity of the SWNTs/PPA-2 composite is measured, indicating a 12% increase of the photocurrent upon the nIR irradiation, which is greater compared with that of the reported pure SWNTs film.

Composites of Functional Poly(phenylacetylene)s and Single-Walled Carbon Nanotubes: Preparation, Dispersion, and Near Infrared Photoresponsive Properties

Single-walled carbon nanotubes (SWNTs) can be dispersed into fine bundles in imidazolium-based ionic liquids (ILs) by simple mechanical grinding. Photoluminescence (PL) of the exciton energy migration from larger band gap semiconducting donor nanotubes to smaller band gap semiconducting acceptor nanotubes within the same SWNT bundle is clearly observed and can be explained by the Forster resonance energy transfer (FRET) mechanism. This offers a simple way to relatively brighten up the PL of those less populated, large diameter, small band gap SWNT species. Taking surfactant sodium dodecyl sulfate (SDS)-dispersed samples as a control of individually dispersed SWNTs, incomplete thermalization before exciton recombination is demonstrated in IL-dispersed SWNT bundles.

Yilun Li

Papers

Chirality-specific growth of single-walled carbon nanotubes on solid alloy catalysts

Dispersing carbon-based nanomaterials in aqueous phase by graphene oxides.

Composites of Functional Poly(phenylacetylene)s and Single-Walled Carbon Nanotubes: Preparation, Dispersion, and Near Infrared Photoresponsive Properties

Photoluminescence from Exciton Energy Transfer of Single-Walled Carbon Nanotube Bundles Dispersed in Ionic Liquids