FN - 6th International Conference
Novel Functional Carbon Nanomaterials


Session FN-1 - Growth and Processing

FN-1:IL01  Light Scattering and Emission from Hetero-structures
A.C. FERRARI, Cambridge Graphene Centre, University of Cambridge, Cambridge, UK 

Heterostructures based on layers of atomic crystals have a number of properties often unique and very different from those of their individual constituents and of their three dimensional counterparts. The combinations of such crystals in stacks can be used to design the functionalities of such heterostructures. I will show how Raman spectroscopy can be used to fingerprint such heterostructures, and how these can be exploited in novel light emitting devices, such as single photon emitters, and tuneable light emitting diodes.

FN-1:IL02  Highly Efficient Solar-fuel Photocatalysts for CO2 Reduction to Selective Hydrocarbons
KUEI-HSIEN CHEN1,2, INDRAJIT SHOWN1, LI-CHYONG CHEN2, 1Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan; 2Centre for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan

Photocatalytic carbon dioxide (CO2) conversion to hydrocarbon fuels, making possible simultaneous solar energy harvesting and CO2 reduction, is considered as a two-birds-with-one-stone approach to solving the energy and environmental problems. However, the development of solar fuels has been hampered by the low conversion efficiency and lack of product selectivity of the photocatalysts. Here, we present defect engineering in some novel 2D materials, particularly, the carbon-doped SnS2 (abbreviated as SnS2-C) nanosheets and reduced graphene oxides, as a viable method towards promising photocatalysts for CO2 reduction reaction (CO2RR). For the first case, the SnS2-C nanosheets with a typical layer thickness of ~40 nm were synthesized using an L-cysteine-based hydrothermal process. Compared with undoped SnS2, the interstitial carbon doping induced microstrain in the SnS2 lattice, resulting in different photo-physical properties. Density functional theory calculations were performed for differently configured SnS2-C for CO2RR. The SnS2-C exhibited a highly effective photo-catalytic activity in gas phase with a photochemical quantum efficiency exceeding 0.7 % under visible light, which is ~250 times higher than that of its un-doped counterpart, and also a world-record high value reported for inorganic catalyst. For the second case, using graphene oxides (GOs), their related two-dimensional (2D) materials and hybrids, as photo-catalysts, will be presented. Several approaches have been employed to synthesize GOs and reduced GOs (rGOs) with tunable bandgap and band alignment with respect to the CO2 reduction level. The functionalities of the GOs/rGOs were investigated by UV-Vis, cyclic voltammetry, and x-ray photoemission spectroscopy.  Under visible light, the photo-catalytic conversion of CO2 to methanol of GOs/rGOs is several-fold higher than that of TiO2 (e.g., commercial P-25). Further, metal and metal dichalcogenide, such as MoS2, were deposited onto GO as co-catalysts or sensitizers, to enhance the photo-catalysis reaction. Besides methanol, other selective hydrocarbons including acetaldehyde and ethanol were also detected. Total solar-to-fuel yield of ~200 times enhancement over that of P-25 has been achieved. In all these GOs-2D hybrids, the photo-catalytic performance is always much better than that of constituent component when used alone. Detailed preparation and characterization of the catalysts will be presented. The role and interplay of the constituent components will also be discussed.

FN-1:IL03  Preparation and Applications of Hybrid Graphene Hydrogels
E. VAZQUEZ, Instituto Regional de Investigación Científica Aplicada (IRICA), Universidad de Castilla-La Macha, Ciudad Real, Spain

The synthesis of different soft polymer networks, by in situ polymerization in the presence of graphene derivatives, is one of the followed approaches to attain a three-dimensional nanocomposite scaffold. The role of the nanomaterial within the polymer network is primarily intended for the reinforcing (i.e. increasing the stiffness and toughness). However, the presence of graphene can also enhance features such as biocompatibility, smart behavior, based on responsiveness to external stimuli, or self-healing ability, giving rise to truly hybrid composites. These syntheses require the production of large amounts of graphene materials, and for this reason, top-down methods, such as exfoliation of graphite, are generally favored. Ball milling of graphite in the presence of melamine, developed in our labs, has proven a method of choice to exfoliate graphite and generate dispersions of few-layer graphene in many solvents, including water. During this talk, we will discuss (i) optimized ways to generate graphene in solvents using ball milling; (ii) the use of graphene dispersions in water for the preparation of hybrid hydrogels as new electroactive scaffolds with self-healing properties.

FN-1:IL05  Soft Processing (= Green Processing) for Nano Carbons: Direct Fabrication of Functionalized Graphenes and Their Hybrids Inks via Submerged Liquid Plasma [SLP] and Electrochemical Exfoliation [ECE] under Ambient Conditions
MASAHIRO YOSHIMURA, J. SENTHILNATHAN, K. SANJEEVARAO, E. SATHEESHKUMAR, Promotion Centre for Global Materials Research (PCGMR), Dept. of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan

Nano-carbons like Graphenes have greatly been interested in various fields of researches, where the large scale synthesis of nano-carbon should be free from using excess energies for firing, sintering, melting, vaporizing and/or expensive equipments. We, propose here Soft processing (=Green Processing) of functionalized Graphenes at ambient conditions. The Soft processing provides number of advantages which includes (a) simple reaction set up,(b) at ambient conditions, (c) simple procedure and (d)less operating costs and wastes. In the present study, we have utilized “Submerged Liquid Plasma [SLP]” and “Electrocemical Exfoliation [ECE] methods. SLP methods resulted the direct synthesis of Nitrogen functionalized Graphene Nano-sheets from Graphene suspension and/or Graphite electrode in acetonitrile liquids. [1,2] Products contains few layers (< 5) Graphene nanosheets. Unsaturated or high energy functional group (e.g. C=C, C=N and C≡N) have formed in the products. We could confirm those functionalized Graphenes are electrochemically active. Using pencil rods instead of Graphite rods we have also succeeded to prepare the Nano-clay/Graphene hybrids by this SLP methods [3]. Reduction and functionalization of Graphene oxides [2] and Synthesis of Graphene/Au Hybrids [4] also realized by SLP. In the ECE, graphite anode is exfoliated electrochemically by H2O2-NaOH [5,6] or Glycine-H2SO4 [7] aqueous solutions under ambient temperature and pressure, for 5-30 min with +1-+5 volt, into 3-6 layers Graphene Nanosheets [GNs]. Those conditions are much milder than those reported before using other chemicals like ionic liquids and/or H2SO4-KMnO4, etc., because O22- ions or ionic complex like Glycine-HSO4- would assist the exfoliation of graphite layers. Our products: GNs suspended in solutions can be transformed in the 2nd step in the same container using BrCH2CN/dioxane into N-FG, further into Au-Hybridized N-FG by the sonification with Au nanoparticles. We have confirmed the excellent catalytic performance of those hybrids [5,6] It should be noted that Soft Processing can directly produce “Graphene Ink”; Graphenes dispersed in various liquids, under mild conditions. Other 2D materials like MoS2 can also be dispersed in a Solution via Sonochemical and/or Electrochemical ways.[8,9]
References: 1) J. Mater Chem A, (2014) 2, 3332; 2) Scientific Reports, 4(2014), 04395; 3) Carbon,78 (2014),446; 4) J. Mater Chem A, 2015, 3,3035-3043,5) Sci. Rep. 4 ,4237 (2014); 6) Nanoscale (2014) 6,12758; 7) Adv. Funct. Mater. 2015, 25, 298-305. 8) Sci. Rept. 2016, Aug. 18, 9) J. Phys Chem C,121,19983,2017.

FN-1:IL06  Graphene Exfoliation and Processing
A. CIESIELSKI, Institut de Science et d’Ingenierie Supramolećulaires (ISIS), Université de Strasbourg and CNRS, Strasbourg, France

Graphene, a one-atom thick two-dimensional (2D) material, is at the core of an ever-growing research effort due to its combination of unique mechanical, thermal, optical and electrical properties. Two strategies are being pursued for the graphene production: the bottom-up and the top-down. The former relies on the use of covalent chemistry approaches on properly designed molecular building blocks undergoing chemical reaction to form 2D covalent networks. The latter occurs via exfoliation of bulk graphite into individual graphene sheets. Amongst the top-down approaches, liquid-phase exfoliation (LPE), which can be further sub-divided into different methods, i.e., solvothermal-assisted LPE, electrochemical LPE, high-shear mixing, ultrasound- induced LPE and the use of superacids, represents an extremely versatile approach which can be carried out in a variety of environments. During my talk I will highlight recent progress in the field of LPE of graphene and other 2D crystals and discuss the processing and properties of the exfoliated materials.

FN-1:IL07  Controlled Growth of High-quality Graphene and Various 2D Materials for Enhancing their Applications
HIROKI AGO, Global Innovation Center (GIC), Kyushu University, Fukuoka, Japan and National Institute for Advanced Science and Technology (AIST), Tsukuba, Japan

Recent development of graphene research has opened a new field of atomically thin, two-dimensional (2D) layered materials. We have developed an original method, heteroepitaxial chemical vapor deposition (CVD) to synthesize high-quality monolayer graphene with controlled orientation by using Cu(111) crystalline film deposited on c-plane sapphire. This method has been further applied to the growth of uniform bilayer graphene by employing Cu-Ni(111) alloy catalyst. Furthermore, the intercalation of MoCl5 was performed for this large-area bilayer graphene, obtaining low sheet resistance with high air stability. Interestingly, twisted bilayer graphene was found to show higher degree of intercalation than AB-stacked bilayer. Our recent advances of hexagonal boron nitride (hBN) growth and various 2D heterostructures, such as SnS-MoS2, graphene-MoS2, and WS2-hBN heterostructures, are also presented together with their transport and optical properties.
References: Chem. Mater., 28, 4583 (2016). Adv. Mater. 1702141 (2017), Phys. Chem. Chem. Phys. 19, 8230 (2017), Adv. Funct. Mater. 1703448 (2017).

FN-1:IL08  Biomimetic On-surface Growth of Graphene Nanoribbons
HIROSHI SAKAGUCHI, Institute of Advanced Energy, Kyoto University, Kyoto, Japan

We demonstrate a synthesis of graphene nanoribbons (GNRs) by a new concept of “biomimetic heterogeneous catalysis” similar to the enzymatic reactions in biology like a “soft” manner, which is featured by homo chirality, transformation, self-assembly and adaptation, directing an optimized chemical reaction pathway to efficiently produce the product[1]. Our developed two-zone chemical vapor deposition[2] of the “Z-bar-linkage” precursors designed herein, exhibiting flexible as well as complex geometry that allows them to adopt chiral (asymmetrical) conformations on a Au(111) surface, results in the efficient formation of acene-type graphene nanoribbons with a width of 1.45 nm through optimized cascade reactions. These new surface-reactions include the formation of self-assembled homochiral polymers in a chain with a planar conformation, followed by efficient stepwise dehydrogenation via a conformation-controlled mechanism. Our proposed concept of “biomimetic heterogeneous catalysis” is useful to fabricate the new nanocarbon materials.
[1] H. Sakaguchi, et al. Nature Chem., 9, 57 (2017). [2] H. Sakaguchi, et al. Adv. Mater., 26, 4134 (2014).

FN-1:IL09  Towards the Intrinsic Mobility Limit of CVD Grown Graphene
C. STAMPFER, JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, Germany

Over the past years many promising applications of graphene have been demonstrated on individual devices. In order to advance from basic research towards scalable industrial applications, large area high quality graphene is needed. One promising approach to achieve this is chemical vapor deposition (CVD) of graphene on copper. However, so far the charge carrier mobility of CVD grown graphene has been significantly lower than what has been observed in devices fabricated from exfoliated graphene. Here, I will show that the electronic quality of CVD graphene depends critically on the transfer method and we present a novel dry transfer technique for CVD-grown graphene crystals that yields devices encapsulated in hexagonal boron nitride (hBN) with carrier mobilities up to 850,000 cm2/(Vs). In addition to the diffusive transport in such samples, we demonstrate an elastic mean free path exceeding one micrometer at temperatures of up to 200 K using Hall cross devices. By investigating large samples we furthermore conclude that the mean free path can exceed 25 micrometer at 2 K. Finally, I will discuss strategies for reaching the intrinsic electron-phonon limited carrier mobility in CVD graphene.

FN-1:IL12  Epitaxial Graphene on SiC - Status and Prospects
R. YAKIMOVA, I. SHTEPLIUK, M. VAGIN, I.G. IVANOV, T. IAKIMOV, G.R. YAZDI, J. ERIKSSON, Linkoping University, IFM, Linkoping, Sweden

Epitaxial graphene on SiC is an appealing material system towards engineering of novel nanostructures and devices. Being a novel integrated structure, graphene on SiC is a promising candidate for devices not only in combination with SiC but also with Nitrides. Furthermore, epitaxial graphene is a unique contender for highly sensitive gas and biosensors. In this talk we are going to discuss the main challenges of graphene growth on SiC e.g. the topological diversity and ways to control the process of uniform monolayer formation. The so-called buffer layer determines the interface between graphene and the SiC substrate, and the subsequent graphene formation and its properties. A second challenge is the appearance of step bunching upon heating of a SiC substrate which results in surface/interface roughening. We will address formation of bilayer inclusions in Si-face grown graphene and their influence on the electronic properties and sensitivity to ambient conditions, e.g. adsorption of functional groups. Anodization of graphene as an electrode will be discussed. We will present examples of gas sensing ability and the sensitivity towards toxic heavy metals. Finally, conclusions reflecting the current progress of the material development and a brief outlook will be given.

FN-1:L13  Integrated Synthesis of Nitrogen and Sulfur Co-doped Carbon Spheres from Melamine and Biaminobenzenesulfonic Acid as Superior Catalyst for Selective Oxidation of Aromatic Alkanes
RONGWEN LYU, M.H. LIU, Dalian University of Technology, Dalian, Liaoning, China 

A fabrication method to prepare nitrogen and sulfur co-doped carbon nanospheres (denote as NS-CSs) from melamine and biaminobenzenesulfonic acid is presented. This method is based on the formation of Schiff base, a imine, between biaminobenzenesulfonic acid and formaldehyde and the following addition of melamine to the carbon–nitrogen double bond of the imine, yielding a nitrogen and sulfur co-doped resin spheres in water at room temperature. Then, NS-CSs are obtained by the direct pyrolysis of the resin spheres. This study determined the conditions for controlling the size of resin spheres. Results showed that the size of resin spheres depended on the melamine concentration, ammonia concentration, 2,4-diaminobenzenesulfonic acid concentration, reaction temperature, and reaction time. The resin spheres diameter could be controlled in the range of 170-800 nm. This prepared NS-CSs show a superior metal-free carbocatalyst for the selective oxidation of aromatic alkanes in aqueous solution. This surprisingly simple method thus enables synthesis of nitrogen and sulfur co-doped carbon nanospheres at large-scale and low-cost with the potential for a wide range of fundamental studies and applications, including, for example, catalyts, sorbing materials, and high-performance electronics.

FN-1:L15  New Approaches for Preparation of Graphene-based Structures with the Intended Chemical Composition from Graphene Oxide
M.K. RABCHINSKII, A.T. DIDEIKIN, M.V. BAIDAKOVA, V.V. SHNITOV, D.A. KIRILENKO, S.V. KONIAKHIN, A. YA. VUL', Ioffe Institute, St.Petersburg, Russia; F. Roth, TU Bergakademie, Freiberg, Germany

Considering its outstanding properties graphene is regarded as a perspective nanocarbon material for various applications in the fields of energy storage, biochemistry, catalysis, optoelectronic devices, etc. However, preparation of graphene and graphene-based structures in large scales for commercial applications still remains a challenging task, giving rise to intensive studies in this field. In this work we present green, facile and easy scalable approach to the synthesis of graphene films and three-dimensional structures simply through low-temperature heating (at 80 °C) of the GO suspension in the presence of sodium silicate or alkali-barium silicate glass substrates. The obtained results do demonstrate that graphene films with good structural quality and high conductivity can be prepared by this technique. Moreover, rGO mesoporous structures grafted with silica groups can be formed by the use of alkali silicates instead of glass substrate during the reduction process with further use of the formed structure in energy storage applications. Thus, the presented approach can be effectively used for low-cost bulk-quantity production of graphene and graphene-based materials.
The presented work was financially supported by the Russian Foundation for Basic Research Grant 15-02-05153

Session FN-2 - Structural Characterization

FN-2:IL02  Vibrational Spectroscopy Characterization of Nanographenes and Polyynes
M. TOMMASINI, Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, Milano, Italy

Vibrational spectroscopy is a useful probe of molecular structure and it has been successfully used to characterize many advanced materials of current interest, among which graphene nanostructures [1-3], and polyynes, i.e., atomic wires made of carbon in sp hybridization [4]. One of the key issues in dealing with Raman spectroscopy of these systems is the fact that π-conjugation drives long-range vibrational interactions, which make the spectra dependent upon the molecular size in characteristic ways. While simple systems such as polyynes can be theoretically investigated in great details, at the analytical level, other important systems such as graphene nano ribbons (GNRs) are too complex to allow this kind of approaches. Hence, Density Functional Theory (DFT) calculations are very useful to discuss structure- and size-dependent spectroscopic features which could be used for the characterization of this class of materials.
References [1] Xiao-Ye Wang et al., J. Am. Chem. Soc., 2017, 139, 4671; DOI: 10.1021/jacs.7b02258. [2] W. Yang et al., J. Am. Chem. Soc., 2016, 138, 9137; DOI: 10.1021/jacs.6b03014. [3] M. Daigle, et al., Angew. Chem. Int. Ed., 2017, 56, 6213; DOI: 10.1002/anie.201611834. [4] C.S. Casari, et al., Nanoscale, 2016, 8, 4414; DOI: 10.1039/c5nr06175j

FN-2:IL03  Advanced Electron Microscopy Techniques applied to Carbon Nanomaterials and Composites
O. ERSEN, G. MELINTE, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504 CNRS - Université de Strasbourg, Strasbourg Cedex, France

The optimization of the properties of the carbon nanomaterials requires in-depth analysis of their structural, morphological and chemical features. In a transmission electron microscope (TEM), combining the classical imaging and spectroscopic modes with the 3D and in-situ approaches allows uncovering materials 3D characteristics, properties and dynamical behavior. A special focus is put here on three modes: in-situ TEM, quantitative tomography and operando environmental TEM. The in-situ TEM is adapted for assessing the evolution of carbon nanostructures in real time under thermal or electrical constraints, the electron tomography gives access to quantitative analysis of their 3D structural and chemical parameters, whilst the latter offers an elegant solution for solving their behavior under realistic environmental conditions. The aim of this contribution is to illustrate through highlighting examples the recent progress in the use of TEM to fulfill the gap between the development of new carbon-based nano-architectures, their characterization and properties. More generally, this contribution aims at providing to carbon nanomaterials scientists a representative set of studies for illustrating the capabilities of the modern TEMs that can be transposed to their own research.

FN-2:IL04  Small Angle Neutron Scattering for Characterization of Carbon Nanostructures 
V.T. LEBEDEV, Saint-Petersburg Nuclear Physics Institute, National Research Center "Kurchatov Institute", Saint-Petersburg, Russia

Review of neutron scattering techniques for the analysis of structure of various carbon atomic clusters and particles is presented. Intense neutron beams provided by high-flux reactors or spallation sources are widely used to recognize atomic, molecular and magnetic ordering (self-assembly) in a variety of carbon and hybrid (metal-carbon) systems such as fullerenes, endofullerenes, nanotubes, graphenes and numerous derivatives, e.g. water-soluble for magneto-resonance imaging. It gives rise to the developments of the powerful method of isotopic contrasting the specimens to study selectively the structure and dynamics of their components (atomic groups, molecular fragments, nanoparticles, polymer chains etc.). A substantial advantage of neutrons as compared to X-rays is associated with a special interaction of neutrons with magnetic atoms and structures in the samples (e.g. magnetic constituents in carbon structures like 3d-elements in nanotubes encapsulated). Highly developed polarized neutron techniques for small-angle elastic and inelastic scattering (e.g. high resolution Neutron Spin Echo method) serve to decode atomic (molecular) and magnetic structures with the evaluation of nuclear-magnetic correlations.

FN-2:IL05  Interface and Properties of Nanocrystalline CVD diamond on AlGaN/GaN Heterostructures
K. HAENEN, Hasselt University, Institute for Materials Research (IMO), Diepenbeek, Belgium; IMEC vzw, IMOMEC, Diepenbeek, Belgium

Diamond is a prime candidate for improving device reliability of GaN based high power-high frequency devices. Here, the case of diamond on GaN-based HEMT structures is considered. While the transient thermoreflectance technique was employed to study the heat spreading capabilities of the diamond films, high resolution cross-sectional TEM in combination with EELS can shed light on the structural properties and chemical composition of the different interfaces. Diamond layers were grown up to a thickness of 2 µm and cross-sectional TEM and EELS mapping of the sample specimens are employed to extract possible changes in composition in the underlying SiN/AlGaN/GaN interfacial layers. For extracting the 2DEG properties, three different possible approaches are presented and evaluated to determine the electron concentration of the HEMT layers before and after diamond growth. The evaluation of the effective thermal conductivity of diamond layers shows an effective maximum thermal conductivity κ reaching a maximum of 200 W/mK for films of 1 to 2 µm thickness. The interfacial thermal boundary resistance TBRDiamond/GaN of diamond ranges from 50 to 90 m2K/GW in samples grown at relatively high deposition temperatures of ~ 650 °C.

FN-2:IL06  Potential Environmental Impact of Carbon Nanomaterials
E. FLAHAUT1, L. LAGIER2, L. EVARISTE2, A. MOTTIER2, F. MOUCHET2, P. LONCHAMBON1, G. CHIMOWA1, B. SOULA1, A.-M. GALIBERT1, E. PINELLI2, L. GAUTHIER2, 1CIRIMAT, Interuniversity Engineering and Research Centre on Materials UMR CNRS-UPS-INPT N°5085, Toulouse, France; 2ECOLAB, University of Toulouse, CNRS, INPT, UPS, Castanet-Tolosan, France

The increase in carbon nanomaterials (CNMs) production (carbon nanotubes, graphene and related materials) is driven by many applications – some of which being already on the market (paints, nanocomposites, etc.). Questions are raising about their safe handling and use (mainly for workers, including researchers), but also about their end of life in the environment. The collaboration between CIRIMAT and ECOLAB has focused on the environmental issues related to CNMs for about 10 years now. After describing briefly the synthesis of the different CNMs used in our work, we will summarise and compare the results obtained in terms of their ecotoxicity on different models (amphibians [1-3], algae [4, 5], etc.). We will discuss some issues about the influence of sample processing and exposure protocols as well as of the metrics for the comparison of the results [6, 7]. Finally, we will discuss how a "safe by design" strategy can be used to allow safe applications of nanocarbons.
References [1] Nanomed., 5, (6), (2010), 963; [2] Carbon, 54, (2013), 175; [3] Env. Chem., 98, (8), (2016), 829; [4] Carbon, 88, (2015), 113; [5] Carbon, 113, (2017), 139; [6] Nano Lett., 16 (6), (2016), 3514; [7] Curr. Op. Biotechnol., 46, (2017), 1-6; Graphene flagship (grant n°604391) support is acknowledged

FN-2:IL07  Measurement of Graphene/Metal Contact Resistance using Kelvin Probe Force Microscopy
W. MERTIN, G. BACHER, Universität Duisburg-Essen, Werkstoffe der Elektrotechnik and CENIDE, Duisburg, Germany; C. ALVARADO CHAVARIN, present address: Innovations for High Performance Microelectronics IHP GmbH, Frankfurt (Oder), Germany

Graphene is a promising material for electronic or optoelectronic devices. The performance of devices based on this material is significantly influenced by the graphene/metal contacts. With modern electrical scanning probe microscopy (KPFM) techniques we investigated the role of the carbon-to-oxygen ratio, the influence of process residues and the impact of contact strategies on the graphene/metal contact resistance. In functionalized graphene sheets we found a change from Schottky-type to nearly metal-type contacts with increasing C/O ratio, which was accompanied by a change in the charge transport mechanism in the graphene [1]. In case of CVD graphene based devices prepared by optical lithography, we could correlate the high contact resistance of above 1000 Ohmµm to a residual optical resist layer with a thickness of 3 - 4 nm between the metal and the graphene channel in case of standard 2D contact geometries [2]. New 1D contact architectures have been introduced to circumvent these problems. We found significantly lower contact resistances of less than 130 Ohmµm [3].
[1] C. Punckt et al., Appl. Phys. Lett. 102, 023114 (2013). [2] C. Alvarado Chavarin et al., Appl. Phys. A 122, 58 (2016). [3] M. Shaygan et al., Ann. Phys. 1600410 (2017)

FN-2:L08  Laser-induced Breakdown Spectroscopy: A Perspective Method for Nanocarbon Materials Characterization
V.F. LEBEDEV, N.V. NIKONOROV, ITMO University, Saint-Petersburg, Russia; M.K. RABCHINSKII, A.V. SHVIDCHENKO, A.Ya. VUL’, Ioffe Institute, St. Petersburg, Russia

Precise and express analysis of structure and chemistry of nanocarbon materials still remains one of the key tasks in the field of studying and following application of these unique structures. Despite large variety of the analytical techniques have been commonly used for this purpose, development of new methods that will further expand efficiency of the nanocarbon materials characterization is yet needed. In the present work applicability of laser-induced breakdown spectroscopy (LIBS) for analysis of chemical composition of different types of nanocarbon structures, namely graphene oxide, reduced graphene oxide and detonation nanodiamonds in the form of thin films is demonstrated. We show that functionalization parameters, such as functionalization degree and predominant type of the functional groups as well as presence of various inorganic contaminants can be effectively determined by this technique. Furthermore, concentration of the distinct species and layer thickness can be also evaluated using LIBS method. Thus, considering also versatility of the LIBS technique and absence of specific requirements to parameters of the studied sample, use of this method seems to be quite an effective approach for analysis of nanocarbon materials structure and chemical composition.

Session FN-3 - Properties

FN-3:IL02  Electronic and Magnetic Structures of 3D Disordered Network of Nanographene Sheets under Heat Treatment at High Temperatures
TOSHIAKI ENOKI, Department of Chemistry, Tokyo Institute of Technology, Tokyo, Japan  

We investigated how spin-polarized edge states vary when nanographenes are subjected to heat-treatment (HT) using 3D disordered network of nanographenes. In nanographene edges terminated with oxygen-containing groups and hydrogen atoms in the pristine sample, oxygen-containing groups are decomposed under HT up to 1300−1500 K and it results in enhancing the inter-nanographene electron transport. HT above 1500 K removes hydrogen atoms, promoting successive fusion of nanographenes. The fusion leads to the random formation of local π/sp2 bridges between nanographenes in the percolative manner and brings about an insulator-to-metal (I-M) transition at ca.1500 K, above which the bridge network becomes infinite. The I-M transition is accompanied by a change in the magnetism from localized spin magnetism to Pauli paramagnetism. Spin glass state appears around the I-M transition. The edge state concentration decreases above 1500 K, demonstrating the successive disappearance of the spin-polarized edges, though the edge-state spin starts decreasing ca. 200 K lower than the temperature at which the edge state concentration starts decreasing. This indicates the development of antiferromagnetic short-range ordering as a precursor of a spin glass near the I-M transition.

FN-3:IL03  Carbon Materials for Sodium-ion Batteries – and the Intriguing Case of Reversibly Intercalating Solvated Ions into Graphite
P. ADELHELM, Jena University, Jena, Germany  

Sodium-ion batteries (SIBs) are recently being reconsidered as potential alternative to lithium-ion battery technology with the hope to realize more cost-effective energy stores that are less susceptible to resource limitations. Currently, hard carbon is the most studied anode for SIBs, however, several challenges need to be mastered. Interestingly, graphite, being the anode material of choice in LIBs does not work in SIBs. This unexpected behavior can be circumvented by intercalating solvated sodium ions rather the naked Na+. In this presentation, we discuss the state-of-the art of carbon materials for SIBs, important challenges and contenders as well as the special concept of intercalating solvated ion.
Refs: Nayak P. K, Yang L., Brehm W., Adelhelm P., From Lithium-Ion to Sodium-Ion batteries: Advantages, Challenges, and Suprises, Angew. Chemie Int Ed., 2017, DOI: 10.1002/anie.201703772 Jache B. and Adelhelm P., Use of Graphite as a Highly Reversible Electrode with Superior Cycle Life for Sodium-Ion Batteries by Making Use of Co-Intercalation Phenomena, 2014, DOI: 10.1002/anie.201403734

FN-3:IL05  Functionalization in Graphene and Related Hybrids for Applications in Hydrogen Evolution Reaction
LI-CHYONG CHEN, Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan; KUEI-HSIEN CHEN, Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan   

Functionalization or hybridization of graphene can lead to significant enhancement in its electro-catalytic properties. Two cases will be presented here. Firstly, graphene nanowalls with controllable strains were synthesized by microwave plasma-enhanced chemical vapor deposition. In strained graphene, the carbon-to-carbon bonds varies, inducing changes in its electronic states and localized electron distribution, consequently, affecting its catalytic reactions. Using Pt nanoparticles loaded graphene nanowalls as electro-catalyst for hydrogen evolution reaction (HER), the polarization curves showed a clear tendency with increasing compressive strain, whereas the Tafel plots indicated that the HER mechanism on Pt was changed, from Volmer-Tafel to Volmer- Heyrovsky, due to shifting in the d-band of Pt and the Pt-H bonding energy. Secondly, we explore the use of hybrid graphene-macrocyclic compounds as low-cost catalyst for efficient HER. Pyrolyzed vitamin B12-supported on graphene showed an unexpected enhanced HER catalytic activity with low over-potential and high turnover frequency, superior to most traditional non-precious metal catalysts in acidic media. X-ray absorption studies revealed a charge-transfer from carbon to cobalt, downshifting the d-band of Co.

FN-3:IL06  The Organic-2D Transition Metal Dichalcogenide Interface
ANDREW T.S. WEE, Department of Physics, National University of Singapore, Singapore  

We have previously shown that the electronic properties of graphene can be controllably tuned via molecular functionalization and other surface modifications. In this talk, I will focus on our recent work on 2D semiconducting transition metal dichalcogenides (TMDs) with layer-dependent tunable direct bandgaps, thereby making them suitable for optoelectronic device applications. We use high resolution scanning tunneling microscopy/spectroscopy (STM/STS) to study the atomic strucure and local electronic structure of 2D MoS2 and WSe2 monolayers on HOPG substrates, and show that the electronic bandgaps can be tuned by strain at grain boundaries and dislocations. Using PTCDA as a prototype semiconductor organic molecule, we show that a monolayer TMD can effectively screen an organic-inorganic heterointerface. We demonstrate the fabrication and unravel the electronic properties of a lateral doped/intrinsic heterojunction in 2D WSe2, partially covered with a molecular acceptor C60F48. I will also present our recent work on the opening of an inverted optical gap in monolayer MoS2 on a gold substrate, and demonstrate that gold plasmonic hybrid structures can induce giant photoluminescense enhancement in monolayer WSe2.

FN-3:L08  Oxide Ceramics Toughened by the Addition of Graphene flakes

The effect of added graphene flakes on the mechanical properties of several oxide ceramics was studied. To obtain samples, commercial ceramic powders (Al2O3, Al2O3 – ZrO2 and Y2O3) and graphene oxide (GO) made at the Institute of Electronic Materials Technology (Warsaw, Poland) were used. The obtained composites were based on aqueous mixtures of both components. After drying, they were sintered on different ways: in vacuum furnace without pressing, in uniaxial pressure (HP) furnace or in spark plasma sintering (SPS) equipment. The composites contained from 0 to 3% of GO by weight. It was shown that in some cases the fracture toughness of the ceramics-graphene composite increase about 78%, but bending strength about 42% in comparison to GO-free matrix. The mechanisms of toughening by graphene flakes consisted of crack deflection, bifurcation and bridging. This work showed that a low concentration of graphene flakes is an effective way for toughening of oxide ceramics.

FN-3:L09  Detonation Nanodiamonds. Particles, Hydrosols and Gels
A.Ya. VUL, E.D. EIDELMAN, A.E. ALEKSEENSKIY, A.V.SHVIDCHENKO, A.T.DIDEIKIN, V.S.YUFEREV, Ioffe Institute, St.Petersburg, Russia; V.T. LEBEDEV, YU.V. KUL’VELIS, B.P. KONSTANTINOV, Petersburg Nuclear Physics Institute, National Research Centre “Kurchatov Institute”, Gatchina, Leninradskaya Region, Russia; M.V. Avdeev, Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna, Russia

Over the last few decades, the application area of detonation nanodiamonds (DND) has been essentially restricted due to extreme strength of agglomerates which formed from DND particles. Recently developed methods for deagglomeration of DND and obtaining the stable hydrosols of 4-5 nm diamond crystals opened new application areas for this promising material. In this presentation, we discuss a model for structure of the single DND particle, mechanism of the sol-gel phase transformation. We have revealed formation of hydrogel at increasing concentration of the DND particles higher than 4-7 wt.% and found that the concentration for the hydrosol-hydrogel transformation depends on sign of zeta potential. We have shown that stability of the hydrosol can be explained in the frame of DLVO theory. However, there are some features, which have to take into account a not-spherical double electric layer around every DND particle. This feature is out the DLVO theory. We suggest a new model for hydrosol and hydrogel of diamond nanoparticles Characterization of suspension and gel by light and neutron scattering methods as well as theoretical estimations supports the model. We discuss possibility for preparation of stable DND sols in different liquids.

Session FN-4 - Applications

FN-4:IL01  BDD Multi-electrode e-tongue for Analytical Detection in Complex Media
B. ZRIBI, D. KAMOUNI BELGHITI, E. SCORSONE, P. BERGONZO, CEA-LIST, Diamond Sensors Laboratory, Gif-sur-Yvette, France

We developed a multi-sensor detection system composed of an assembly of Boron doped diamond (BDD) electrodes each functionalized using a different catalyst metals. Metallic nanoparticles (5 – 10 nm) were prepared onto BDD with a dense distribution typically around 20-100nm. Nanoparticles of different metals as well as alloys (e.g., Pt, Ir, Au or PtIr etc) were used as catalysts. Their stability was assessed in terms of electro-activity and adhesion, as challenged under the continuous repetition of amperometric cycling measurements as well as pulses of high current density (> 50mA.cm-2). The approach enabled, from the fine complementarity of an array of such metal functionalized electrodes, to obtain a characteristic chemical fingerprint of the product to detect. By coupling such a detection device with algorithmic learning / recognition methods, the system provides an improved selectivity, in a similar way to an “electronic tongue”. This was applied to several case studies, as will be presented for food contaminants, pesticides, and other complex compounds.

FN-4:IL02  Synthesis, Properties and Applications of Carbon Nanodots
M. PRATO, University of Trieste, Trieste, Italy  

We have recently described a simple, scalable, reliable and cost-effective synthetic process for producing high-quality nitrogen-doped carbon nanodots (NCNDs), by employing arginine and ethylenediamine as precursors. The new material displays among the smallest size and the highest fluorescence quantum yields reported so far. Moreover, they can be easily post-functionalized, due to the abundant presence of amino groups. These new NCNDs can act as powerful alternative to the conventional co-reactant species for electro-chemiluminescence generation. We have also presented a rational synthetic design for mastering CND properties, showing the importance in the choice of the precursors. By using properly designed functional units, the desired properties can be modulated, from the molecular to the nanoscale level in a controlled fashion. CNDs with customized emission can therefore be approached. Green, red and finally white-emitting CNDs were synthesized. Finally, preliminary investigation on their cytotoxicity, cell uptake and imaging capability, and on their employment for LED fabrication, suggested their potential for various applications. During this talk, we will communicate our latest results in this fast developing field.

FN-4:IL03  Nanocarbons and Carbon Nanotubes -Safe Innovation and Promise for the Future-
MORINOBU ENDO, Shinshu University, Nagano, Japan  

Carbon nanotubes (CNT) carry a vital role as a leading material for green nanotechnology innovation of the 21st century. CNT exhibits excellent properties due to the nano-1D structure1). CNT have achieved a successful development in science and reasonable production. At present, we are trying to gain public engagement based on the concept of ‘‘safe innovation’’ and ‘‘responsible production and use’’ by appropriate risk control. In fact, manufacturing and applications of CNT have been developed by taking safety into consideration. LIB and various composite materials have been pioneered as useful applications, which will be introduced in the presentation. Efforts have been made to understand the toxicity of CNT, and special attention must be paid to all of the processes related to CNT until socially acceptable risk control protocols will be established.  The accumulating knowledge on CNT safety and toxicity evaluation make it possible to contribute to the green and safe innovation with nanocarbons and CNT as a model for new material development in the 21st century, as our important promise of the future.
References: 1. M. Endo, Japanese Journal of Applied Physics 51,040001 (2012)

FN-4:L04  Understanding the Kinetics of Heavy Metals on Epitaxial Graphene: Towards Monitoring the Water Quality
I. SHTEPLIUK, M. VAGIN, I. IVANOV, T. IAKIMOV, R. YAKIMOVA, Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden

Due to its unique electronic properties and large surface area, providing sufficient number of electrochemically active sites for redox reactions, epitaxial graphene formed by the high-temperature thermal decomposition of Si-face SiC (0001) in argon is a promising working electrode material for electrochemical detection of heavy metals (HMs) in aqueous solutions. To understand and to further improve HM detection limits, responsivity and selectivity of the epitaxial graphene, it is necessary to gain deep insights into a nature of a behaviour of the HMs onto basal plane of graphene. Here we report the results of the electrochemical studies (cyclic voltammetry and chronoamperometry), Raman characterization and density functional theory (DFT) calculations allowing us to study the nucleation mechanisms, diffusion and binding order of cadmium, mercury and lead species onto epitaxial graphene. Epitaxial graphene shows high sensitivity to Pb (2.07 μg·L-1) compared to other metals. The chronoamperometric measurements showed that the initial kinetics of the Pb species is governed by the 3D diffusion-controlled instantaneous nucleation mechanism. The diffusion coefficient of Pb is found to be 3.358·10-8 cm2·s-1, suggesting the high activation energy for surface migration of Pb species.

FN-4:IL05  Carbon Nano-onions as Nanoprobe for Cancer Therapy
S. GIORDANI, Department of Chemistry, Università di Torino, Turin, Italy; and Nano Carbon Materials, Istituto Italiano di Tecnologia, Turin, Italy

Carbon nano-onions (CNOs) are structured by concentric shells of carbon atoms and display several unique properties, such as a large surface area to volume ratio, low density and a graphitic multilayer morphology. In my research group we have developed a versatile and robust approach for the functionalisation of CNOs, involving the facile introduction of a number of simple functionalities onto their surface. Our results have shown that chemical functionalization of the CNOs dramatically enhance their solubility and reduce their inflammatory properties in vitro and in vivo. We reported the absence of adverse effects induced by CNOs on short and long term toxicity in Hydra and in zebrafish suggesting a reasonable degree of biosafety of this new class of nanomaterials. We have developed intracellular imaging systems based on CNOs. Special attention was given to the biologically important near-infra red (NIR) region. CNOs functionalised with NIR emitting BODIPY derivatives show good cellular uptake, and a pH dependent fluorescence on-off switching. We have developed a synthetic multi-functionalisation strategy for the introduction of different functionalities (receptor targeting unit and imaging unit) onto the surface of the CNOs.

FN-4:IL06  Side-gated Nanoscale Diamond Transistors
A.C. PAKPOUR-TABRIZI, R.B. JACKMAN, London Centre for Nanotechnology and the Department of Electronic and Electrical Engineering, University College London, London, UK

A diamond side-gated nano-transistor (SG-NT) is proposed and demonstrated for the first time. Thin boron doped layers (~5nm) were utilized, then being processed using e-beam lithographic methods with carefully selected resist technology to enable the formation of side-gated transistor structures. An impressive channel depth of 5nm and a channel width of 20nm were achieved. Gate lengths in the 20-500nm range were investigated. These devices are ‘normally-on’ (depletion-mode) devices, which display clear channel modulation and pinch-off – key characteristics for any transistor. Further, they show clear quantum-transport phenomena – an absolute first for diamond devices of this type. This presentation will introduce the fabrication methodology, the results achieved to date and the prospects for this exciting break-through technology.

FN-4:IL07  Optimization of Gate Oxide for Reliable Diamond Power Transistors
E. GHEERAERT, Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France

Semiconducting diamond is an attractive candidate for the next generation of high voltage and high frequency power devices, thanks to his exceptional properties in terms of wide bandgap, high breakdown field and thermal conductivity. In the literature, several diamond-based field-effect-transistors (FETs) have already revealed good on state performance and high blocking voltage capability (~2kV) in a wide range of operating temperatures. The possibility of generating an inversion regime in diamond metal-oxide-semiconductor FET (MOSFET), and the new Deep Depletion regime (D2MOSFET) specific to wide bandgap semiconductors pave the way for a new generation of power devices. The critical part of the transistor is the gate oxide, with electrical charge traps located within the oxide or at its interface with the semiconductor. These traps can screen the gate potential and shift the threshold voltage, making the devices unusable. The reduction of the trap density is a major concern in all MOS technologies, as well as its stability with time under bias stress. The latest results about diamond MOS transistors prepared in the framework of the European GreenDiamond project will be presented, and the evolution of the diamond MOS properties with time will be reported for the first time.

FN-4:IL08  Graphene-based Micro-supercapacitors by Flash Lamp Technology
TAEYOUNG KIM, Department of Bionanotechnology, Gachon University, Seongnam, South Korea  

The need to develop micro-supercapacitors compatible is becoming increasingly critical to integrate high power energy storage components directly onto the next-generation electronic devices. Here, we present a method to fabricate flexible micro-supercapacitors based on graphene-based materials and their hybrids with diverse pseudocapacitive materials. The hybrid micro-electrodes consisting of graphene and pseudocapacitive materials were prepared using photonic flash lamp annealing (FLA) technique. The basic principle of flash lamp annealing is the selective heating via light absorption. The intense pulsed light from flash lamp is absorbed by the graphene oxide (G-O) and precursors deposited on the plastic substrate and consequently rapidly convert them into reduced graphene oxide (rG-O) and pseudocapacitive materials in a matter of milliseconds. The micro-supercapacitor built on these hybrid electrode uses both Faradaic and non-Faradaic process to store charges, thereby allowing for reasonably high capacitance. The performance of the micro-supercapacitors will be discussed in terms of electrochemical performances.

FN-4:IL09  Carbon Nanofibers as Support for Pt-Catalysts in PEM Fuel Cells
P.Y. PODLESCHNY, U. ROST, M. BRODMANN, Westphalian University of Applied Sciences, Dortmund, Germany  

High production costs and a moderate durability are still obstacles for the large commercialization of polymer-electrolyte-membrane (PEM) fuel cells. Therefore, an innovative and application-driven research approach is taken by using corrosion stable carbon nanofibers (CNFs) as catalyst support material. Utilized CNFs are provided by Grupo Antolin Ingenieria SA (Spain) and show a high graphitization degree, which yields in a high chemical stability and could contribute to the long-term stability of PEM fuel cells. Additionally, the CNFs provide a large specific surface area, which is needed to create catalyst layers with great performances. In this contribution, an overview about the developed PEM fuel cell electrode preparation process is given. This preparation route deals with the functionalization of used CNF material via low-temperature plasma treatment and the pulsed electrodeposition of catalyst material. In addition, some highlights of the recent research are presented concerning long-term stability, performance achievements as well as catalyst utilization.

FN-4:IL10  Beyond CMOS Solutions Enabled by Layered Materials
G. FIORI, Dipartimento Ingegneria dell'Informazione, University of Pisa, Pisa, Italy

Layered materials can represent an enabling technology for More Moore and More than Moore applications. In this talk, we will provide a perspective of two-dimensional material (2DMs) based electronics, focusing on the solutions which have the higher chances to reach the end-of-the-roadmap, while focusing on the main problems semiconductor industry has to solve, and how 2DMs could represent a valid technological option. We will also provide some perspectives regarding 2DMs inkjet printed devices, as an interesting solution to print on-demand and on flexible substrates electronic systems.

FN-4:L11  Graphene-based Materials for the Fast Adsorption of Biomolecules
M. SEREDYCH1, F. MENG1, L. MIKHALOVSKA2, S. MIKHALOVSKY2, V. MOCHALIN3, Y. GOGOTSI1, 1Department of Materials Science & Engineering and A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA, USA; 2Department of Chemistry, Missouri University of Science & Technology, Rolla, MO, USA; 3School of Pharmacy and Biomolecular Sciences, University of Brighton, Lewes Road, Brighton, UK

This study relates to hemoperfusion for blood cleansing and removal of cytokines from human blood plasma in order to treat sepsis and related diseases. The blood plasma perfuses a filter containing graphene-based sorbents. Graphene materials were chosen based on their open surface structure and interlayer pore size, which is comparable to the size of the proteins to be adsorbed. Our results show that graphene nanoplatelets exhibit high adsorption capacity, but cannot be directly used in filtration due to the risk of small particles getting into the bloodstream. Granulation of this material using PTFE as a binder solves the problem of the particle release without reducing the open surface accessible for the protein molecules. Both materials produced a significant decrease of protein concentrations in blood plasma over a short period of time. These graphene-based adsorbents offer open hydrophobic surfaces fully accessible to proteins, which makes them suitable for use in filtration/adsorption devices for blood purification. Efficient removal of cytokines was shown using a special designed flow system. Graphene nanoplatelets are among the fastest and most efficient sorbents identified to date, greatly outperform porous activated carbons and porous polymers.

FN-4:IL12  Applications of Detonation Nanodiamonds: Today and in Future
A.T. DIDEIKIN, Ioffe Institute, St. Petersburg, Russia

Detonation nanodiamond (DND) – the multitude of perfect faceted 4–5nm sized diamond crystals is one of the contemporary industrial scale nanomaterials. Since its discovery about 50 years ago it got plenty of useful applications but still the most part of them is associated with progress in nanotechnologies. From the beginning DND was regarded as ultrafine polishing material as well as seeding source for chemical vapor deposition (CVD) process for diamond film growth. A little later it was found that DND is very useful component for effective composite materials in combination with metals, oxides, organic polymers especially for thin film coatings. Recent solution of two main problems that long hampered new applications of DND, namely the insufficient purity and, strong agglomeration of primary nanocrystals opened new ways in biology, medicine and nanotechnologies for this unique material. The new application areas do not restricted by luminescent markers for intracellular diagnostics and intercellular targeted delivery systems but propagate to single photon sources for quantum computing, electron sources for field electron emitters as well as precision magnetic sensors. Future of DND seems to be related to reduction of size of particles for access to quantum size effects.

FN-4:L14  Black Diamond Technology for Solar Energy Conversion
A. BELLUCCI1, M. GIROLAMI1, M. MASTELLONE1, S. ORLANDO1, R. POLINI1,2, D.M. TRUCCHI1, 1CNR-ISM, Rome, Italy; 2Dept. of Chemical Sciences and Technologies, Univ. di Roma “Tor Vergata”, Roma, Italy

High-temperature solar cells are possible by exploiting the Photon-enhanced Thermionic Emission (PETE) concept, which represents a novel and very attractive mechanism for the exploitation of solar radiation, especially if concentrated, and characterized by promisingly high conversion efficiency (>50%). Ultrashort pulse laser-assisted surface nanotexturing combined to surface-hydrogenation, aimed at achieving negative electron affinity conditions and a work function as low as 1.7 eV with a nitrogen-doping of the emitting-layer, are here proposed as a radically new and potential effective PETE cathode completely based on CVD diamond. CVD diamond is transparent to solar radiation due to its wide bandgap, consequently black diamond technology was developed for drastically increase absorption coefficient and photogeneration capability under sunlight irradiation. The final p/i/n structure merges the technologies of surface texturing and laser-induced graphitic microchannels, to form an innovative defect-engineered black diamond cathode for the conversion of concentrated solar radiation operating at high temperature. Results under high-flux solar simulator will be reported and discussed by demonstrating for the first time the PETE effect at temperatures from 350 to 550 °C.

FN-4:L15  Redox and Magnetically Active Nanoswitches Encapsulated in Hollow Carbon Nanotubes
M. DEL CARMEN GIMENEZ-LOPEZ, School of Chemistry, University of Nottingham, University Park, Nottingham, UK

The coupling of nanocarbons with redox and magnetically active nano-objects has attracted a great deal of attention for achieving functional hybrid nanostructures with a wide range of exploitable properties. A key challenge for designing next-generation electronic or spintronic devices is the coupling of the nanoscale magnets with the macroscopic world. High-aspect ratio carbon nanostructures can act as bridges to achieve this coupling through the encapsulation of magnetic species, while maintaining their structural integrity and properties. Another important challenge facing the humankind today is the production of clean and sustainable energy where electrochemical technologies have shown to play an important role. However, electrochemical devices based on electrocatalyst containing precious metals, such as Pt, are currently hindered by their short-term durability. As these precious elements are rapidly diminishing, the research community is forced to urgently address this major issue until more abundant efficient electrocatalysts are put forward. In this respect, hollow carbon nanostructures can provide an excellent mean for the fabrication of highly durable electrocatalyst materials through platinum confinement, allowing their sustainable use in fuel cells.

FN-4:L16  Elastocaloric Effect in Carbon Nanotubes and Graphene
S. LISENKOV, University of South Florida, Tampa, FL, USA

Carbon nanotubes are famous for their many extraordinary properties. We use a thermodynamical approach, experimental data from the literature, and atomistic simulations to reveal one more remarkable property of the carbon nanotubes that has so far been overlooked. Namely, we predict the existence of very large elastocaloric effect that can reach up to 30 K under moderate loads. Potentially even larger values could be achieved under extreme loads, putting carbon nanotubes in the forefront of caloric materials. Other remarkable features of the elastocaloric effect in carbon nanotubes include linearity of elastocaloric temperature change in applied force (compressive or stretching), very weak dependence on the temperature, and an absence of hysteresis. Such features are extremely desirable for practical applications in cooling devices. Moreover, a similarly large elastocaloric effect is predicted for the graphene. The prediction of a large elastocaloric effect in carbon nanotubes and graphene sets forward an unconventional strategy of targeting materials with moderate caloric responses but the ability to withstand very large loads.

FN-4:L17  Ammonia Sensing using Transfer-free in situ CCVD Grown Nanocrystalline Graphene
D. NOLL, U. SCHWALKE, Institute for Semiconductor Technology and Nanoelectronics, Technische Universität Darmstadt, Darmstadt, Germany  

Nanocrystalline graphene field effect transistors (nGFET) have been fabricated by the use of our transfer-free PMMA-enhanced in situ catalytic CVD (CCVD) process. By this method, hundreds of nGFETs can be made simultaneously on a single oxidized 2” silicon wafer. The dedicated metal catalyst structures serve as individual electrical contacts, avoiding post-graphene-growth process steps [1]. In this contribution we demonstrate the intrinsic and gas sensing electrical properties of our devices by electrical testing using our self constructed high vacuum probing station. Analysis of the input characteristics of fabricated nGFETs show reduced hole doping at a vacuum pressure of 4E-5 mbar, thus verifying atmospheric doping effects to our devices. Furthermore, ammonia gas sensing experiments are conducted down to a concentration of 200ppb. An increasing electron doping effect over time has been monitored, recovering once the ammonia supply is turned off. Additionally, hysteresis effects of the nGFETs upon exposure to ammonia are observed and will be discussed.
[1] D. Noll, U. Schwalke; ”PMMA-enhancement of the lateral growth of transfer-free in situ CCVD grown graphene”, 13th International Multi-Conference on Systems, Signals & Devices (SSD), 2016.

FN-4:IL19  Aeronautical Composite Laminate Structure Containing Graphene Related Materials
C. MERINO, Grupo Antolin Ingeniería, Burgos, Spain; T. BLANCO, A. BUTRAGUEÑO, Airbus Operations, Getafe, Spain; A. REGUERO, Aernnova, Toledo, Spain; J. LÓPEZ PUENTE, University Carlos III Madrid, Leganés, Spain  

The aeronautic industry is an engineering field in which aircraft architects are looking for new solutions in order to decrease the fuel consumption. The decrease of the aircraft structure weight is one of the subjects that manufacturers are continously studying, and that is the reason why carbon fibre/epoxy laminates are increasingly used to manufacturing civil aircrafts, reaching up to the 50% of the structure in terms of weight. Carbon fibre/epoxy laminates exhibit high specific mechanical properties, but they have some limitations: toughness, compression and impact resistance. Regarding the last limitation, impacts are one of their main drawbacks, since they could be difficult to detect, and they can promote important strength reductions. Low impact resistance is related to the polymer matrix resistance, which could be increased with the use of graphene. An aeronautical composite prototype has been manufactured by means of resin transfer moulding technology, using a epoxy resin doped with graphene in order to improve the impact strength of the structure. This challenge entails the possibility to improve current aerostructure performances without significant changes either in design or in manufacturing process.
Research supported by the H2020 program-Graphene Flagship Project

FN-4:IL20  Graphene-based Neurointerfaces
M. BRAMINI, F. CESCA, F. BENFENATI, Center for Synaptic Neuroscience and Technologies & Graphene Labs, Istituto Italiano di Tecnologia, Genova, Italy  

The emerging interest toward applying nanomaterials for drug and gene delivery, biomedical imaging and diagnostic biosensors within the central nervous system (CNS) prompted neuroscientists to focus on the effects of the interaction of nanostructures in contact with primary neural cells. Our main goal is to evaluate biocompatibility and accordingly any unwanted effects that new materials could potentially induce to the CNS. We are currently pursuing various lines of research inside the Graphene Flagship European project, focusing our attention on graphene-based material interactions with primary neurons and glial cells. We are characterizing the molecular mechanisms of graphene nanosheet internalization together with the possible inflammatory responses, and the possibility of using both 2D and 3D G-based supports as biocompatible scaffolds for biomedical applications. The aim is to exploit the conductive properties of graphene to modulate and control the activity of neural networks grown in strict contact with such structures (i.e. for artificial retina approach). Moreover, we are exploring both the biology of blood-brain barrier when in contact with graphene and its penetration by reconstitution in vitro of the tripartite endothelium/glial/neuronal interface.

FN-4:L21  Nanoscale Sensing using Color Centers in Diamond
A. SLABLAB, M. RADTKE, R. NELZ, E. BERNARDI, A. MEYER, O. OPALUCH, M. CHALLIER, E. NEU, Saarland University, Saarbruecken, Germany  

Individual, luminescent point defects in diamond so called color centers form stable, atomically-sized, solid-state quantum systems. Nitrogen vacancy (NV) centers possess single electronic spins that can be coherently manipulated using microwave radiation and read-out using confocal laser fluorescence microscopy even for single centers. Due to their atomic size and coherent spins, individual NVs are versatile nanoscopic quantum sensors e.g. for magnetic fields and optical near fields. To enable truly nanoscale sensing, it is mandatory to incorporate the centers into highly-functional photonic nanostructures. These structures enable scanning of an NV center close (< 50 nm) to a sample for nanoscale sensing. Simultaneously, they enable high photon rates from single centers. Nanostructures can be formed either in bottom-up or top-down processes, while numerical simulations aid in optimizing their geometry. We also discuss the influence of material properties like the surface termination of the diamond. We highlight novel sensing schemes using color centers based on near field energy transfer processes.

FN-4:IL22  Graphene Transistors in Biosensing Applications
S. ARPIAINEN, M. SOIKKELI, H. AROLA, T. NEVANEN, VTT Technical Research Centre of Finland Ltd, VTT, Finland  

Graphene is extremely promising material for biosensor applications, combining inert and biocompatible surface chemistry with high electrical and optical responsivity. With graphene field effect transistors (GFETs) the sensitivity is based on the high transconductance, turning the minute changes in the dielectric properties and charging in the bioresponsive surface functionalization layer into measurable electronic signal. This provides basis for the development electrical quantitative tools for point-of-care (PoC) and home diagnostics and point-of-application (PoA) environmental and food safety analysis. The competing techniques include semiconductor nanowires, carbon nanotubes and semiconducting polymers with similar operating principles, and some optical analysis methods, part of which are also based on graphene. GFET sensors with femtomolar sensitivity have been demonstrated. The detector selectivity relies entirely on the specificity of the biofunctionalization, which can be based on biological receptors such as antibodies and their fragments, or synthetic peptides. The major challenges in the sensor development for real applications relate to the blocking of the unspecific binding of elements from the analyte media, such as saliva or blood in biodiagnostics, and reliable referencing.

Cimtec 2018

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