Search query: Chemically  derived,  ultrasmooth  graphene  nanoribbon semiconductors

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abstract: We developed a chemical route to produce graphene nanoribbons (GNR) with width below 10 nanometers, as well as single ribbons with varying widths along their lengths or containing lattice defined graphene junctions for potential molecular electronics. The GNRs were solution phase derived, stably suspended in solvents with noncovalent polymer functionalization, and exhibited ultrasmooth edges with possibly well defined zigzag or armchair edge structures. Electrical transport experiments showed that, unlike single walled carbon nanotubes, all of the sub 10 nanometer GNRs produced were semiconductors and afforded graphene field effect transistors with on off ratios of about 107 at room temperature.
author_names: Xiaolin Li

Xinran Wang

Li Zhang

Sangwon Lee

Hongjie Dai
title: Chemically Derived, Ultrasmooth Graphene Nanoribbon Semiconductors
venue: Science
year: 2008

author_names: Xiaolin Li

Xinran Wang

Li Zhang

Sangwon Lee

H Dai
title: Supporting Online Material for Chemically Derived Ultrasmooth Graphene Nanoribbon Semiconductors
year: 2008

abstract: Abstract We investigate the effect of out layer strain on the electronic and transport properties of chemically functionalized hybrid b AGNR systems, which are formed by partial hydrogenation and fluorination (or hydrofluorination) in the middle parts of bilayer armchair graphene nanoribbon, using density functional theory and nonequilibrium Green's function techniques. The calculated formation energies show that all hybrid systems have negative formation energies, thus, they are stable with respect to molecular desorption. Especially, the fluorinated hybrid system is more stable than others, due to higher electronegativity of F than H atoms. From calculated band structures, we reveal that the hybrid systems are the semiconductors with band gaps of about 0.09 eV 1.55 eV as function of nanoroad width and out layer strain. Especially, the band gaps of the hybrid systems with nanoroad width show the order of 3 nanoroad 5 nanoroad 1 nanoroad. The calculated I V curves exhibit that the currents of the hybrid systems as a function of chemical derivation classes increase/decrease with different behavior, while they have similar behavior variations according to out layer strain. More interestingly, the calculated I V curves of hybrid b AFGANR 1 nanoroad system as a function of out layer strain exhibit negative differential resistance within bias voltage range 0.6 V to 1 V. Prime novelty statement In this paper, we investigate the effect of out layer strain on the electronic and transport properties of chemically functionalized hybrid b AGNR systems, which are formed by partial hydrogenation and fluorination (or hydrofluorination) in the middle parts of bilayer armchair graphene nanoribbon, using density functional theory and nonequilibrium Green's function techniques. The results present that all systems are structurally favorable and are semiconductors with band gaps of about 0.09 eV 1.55 eV as function of nanoroad width and out layer strain. Especially, the I V curves of hybrid b AFGANR 1 nanoroad system as a function of out layer strain exhibit negative differential resistance within bias voltage range 0.6 V to 1 V. The above results show that hybrid b AGNR systems would be a promising material for graphene based electronic devices.
author_names: Nam-Chol Ri

Jong-Chol Kim

Su-Il Ri
title: Improvement of the electronic and transport properties of hybrid bilayer armchair graphene nanoribbon by chemical derivation and out layer strain: A first principles calculations
year: 2021

abstract: A nanostructured porous carbon (NPC) is prepared by using a facile physical activation method, with nitrogen doped graphene nanoribbon aerogel and carbon dioxide as a precursor and an activating agent, respectively. The morphology, porosity parameters, and chemical properties of the as prepared NPC have been revealed by using various characterization methods, including scanning electron microscopy, nitrogen sorption analysis, and X ray photoelectron spectroscopy (XPS) The NPC with a moderate nitrogen content (5.1 atom on the basis of XPS analysis) retains the sponge like morphology of nitrogen doped graphene nanoribbon aerogel, shows a high Brunauer Emmett Teller specific surface area (1380 m2 g 1) and possesses hierarchically porous structures. Based on its excellent properties such as high porosity, conductive network, and nitrogen doping, NPC as a superior host is used to fabricate a sulfur based cathode for lithium sulfur batteries. The high specific surface area and the pore volume of NPC not only allow uniform distribution of sulfur in an amorphous form, but also help to alleviate the shuttle effect of polysulfides. As a result, the as obtained cathode exhibits a good rate capability and cycling stability.
author_names: Hang-Yu Zhou

Zhuyin Sui

Shan Liu

Hai-Yan Wang

Bao-Hang Han
title: Nanostructured porous carbons derived from nitrogen doped graphene nanoribbon aerogels for lithium sulfur batteries.
venue: Journal of colloid and interface science
year: 2019

abstract: As the global energy consumption escalates at an alarming rate, the development of clean and renewable energy conversion technologies has become more critical. Solar energy is considered the ideal alternative, since it is the most readily available and richest renewable source of energy. Over the past few years, graphene, a two dimensional (2D) single atomic carbon sheet, has greatly contributed to many advances in solar energy conversion. However, the use of pure graphene alone is limited to the type of functions it can provide, not to mention the challenges that come with its processability. Therefore, the functionalization of graphene is essential for the development of solar specialized graphene based materials. This is achieved by typically integrating graphene into a photoactive material (e.g. semiconductors, organics, and metals) or, less commonly, by the self functionalization of graphene to render it photoactive. Overall, this chapter describes the versatility of functionalization to fabricate sophisticated graphene materials for solar energy conversion in three application categories photovoltaic, photochemical, and photoelectrochemical.
author_names: Lutfi Kurnianditia Putri

Wee-Jun Ong

Lling-Lling Tan

Yi-Hao Chew

Siang-Piao Chai
title: CHAPTER 4:Functionalization of Chemically Derived Graphene for Solar Energy Conversion
year: 2018

abstract: Graphene oxide (GO) has unique physical, chemical, and mechanical properties. It has also acquired great interest for its unique mechanical, electrical, electronic, and optical properties. GO possesses different types of functional groups, which allows it to interact with organic and inorganic materials in covalent, non covalent, or ionic manner. Therefore, GO behaves like a semiconductor due the presence of impurity such as hydroxyl, carbonyl, and carboxyl groups as a functional group. The present paper deals with the synthesis of ultrathin layer of GO from commercially available graphite powder. The synthesis process starts with the chemical oxidation of commercial graphite powder into GO by modified Hummer's and Offeman method. Modified Hummer's method is simple and easily adoptable in laboratory. The obtained GO material was characterized by X ray diffraction (XRD) scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR)
author_names: Pankaj Kumar

Neetu Divya

Jatinder K Ratan
title: Synthesis and Characterization of Chemically Derived Graphene Oxide from Graphite
year: 2019

abstract: Summary The reticular synthesis of covalent organic frameworks (COFs) extended porous two dimensional (2D) or three dimensional (3D) networks held together by strong, highly directional chemical bonds, has thus far been restricted to small, shape persistent, molecular building blocks. Here, we demonstrate the growth of crystalline 2D COFs from a polydisperse macromolecule derived from single layer graphene, bottom up synthesized quasi one dimensional (1D) graphene nanoribbons (GNRs) X ray scattering and transmission electron microscopy reveal that 2D sheets of GNR COFs self assembled at a liquid liquid interface stack parallel to the layer boundary and exhibit an orthotropic crystal packing. Liquid phase exfoliation of multilayer GNR COF crystals gives access to large area >105 nm2) bilayer and trilayer cGNR COF films. The functional integration of extended 1D materials into crystalline COFs greatly expands the structural complexity and the scope of mechanical and physical materials properties accessible through a deterministic reticular bottom up approach.
author_names: Gregory Veber

Christian S Diercks

Cameron R Rogers

Wade Scott Perkins

Jim Ciston

Kyunghoon Lee

Juan Pablo Llinas

Alex Liebman-Pelaez

Chenhui Zhu

Jeffrey Bokor

Felix R Fischer
title: Reticular Growth of Graphene Nanoribbon 2D Covalent Organic Frameworks
year: 2020

abstract: At widths below 10 nm, armchair graphene nanoribbons become semiconductors. One promising route to synthesize nanoribbons is chemical vapor deposition (CVD) of hydrocarbons on Ge(001) and synthesis from seeds reduces nanoribbon polydispersity. In this contribution, we advance the seed initiated synthesis of nanoribbons and explore the impact of seed size and nanoribbon spacing on growth kinetics. Periodic arrays of graphene seeds are lithographically patterned and etched to reduce their diameter. The viability of initiating synthesis from sub 5 nm seeds is demonstrated, and the pitch between nanoribbons is reduced from 500 to 50 nm to show that crowding effects do not perturb nanoribbon growth kinetics. The invariance of kinetics with pitch in combination with density functional theory (DFT) calculations indicate: (1) the growth species for synthesis has a diffusion length 50 nm and/or (2) the kinetics are strongly attachment limited. These results demonstrate that seed initiated synthesis on Ge(001) is a promising route for creating dense arrays of armchair graphene nanoribbons for semiconductor electronics applications.
author_names: Austin J Way

Ellen A Murray

Florian Goltl

Vivek Saraswat

Robert M Jacobberger

Manos Mavrikakis

Michael S Arnold
title: Anisotropic Synthesis of Armchair Graphene Nanoribbon Arrays from Sub 5 nm Seeds at Variable Pitches on Germanium.
venue: The journal of physical chemistry letters
year: 2019

abstract: Label free sensors capable of detecting low concentrations of significant biomolecular substances without inducing immune response would simplify experiments, minimize errors, improve real time observations, and reduce costs in probing living organisms. This paper presents a first principles, in silico derived, all armchair graphene nanoribbon field effect transistor (g FET) device for the detection and measurement of low concentration (pM nM) uridine diphosphate glucose, UDP glucose. UDP glucose is an intermediate reactant in the synthesis of sucrose in a plant cell's cytoplasm and an extracellular signaling molecule capable of activating downstream defense mechanisms. The unique g FET configuration for the semiconducting channel and electrodes favors the fabrication of high density nanoarray sensors. Optimal device electronic transport and switching properties are predicted by screening configurations with different widths, to control bandgap, and lengths, to control thermionic versus tunneling transport across the semiconducting junction. A self assembled monolayer (SAM) of pyrene derivatives, 1 pyrenebutyric acid, is used to noncovalently functionalize the graphene surface on one end and to covalently ligate the target analyte on the other while providing mechanical, chemical, and electronic signal sensing stability. We find that the device offers a predicted limit of detection (LOD) of <italic>0.997</italic><inline formula> <tex math notation="LaTeX"$n$ /tex math>/inline formula> mM/L (where <inline formula> <tex math notation="LaTeX"$n$ /tex math>/inline formula> is the number of sensor units in an array) with high transconductance sensitivity, 0.75 <inline formula> <tex math notation="LaTeX"$1.5\mu \text {S} /tex math>/inline formula> for 1 3 UDP glucose molecules, at low input <inline formula> <tex math notation="LaTeX"$V_{G} 0.9$ /tex math>/inline formula> V) and output voltages <inline formula> <tex math notation="LaTeX"$V_{\text {DS}=0.1$ /tex math>/inline formula> V. Thus, a <inline formula> <tex math notation="LaTeX"$1000\times1000$ /tex math>/inline formula> nanoarray sensor would yield an LOD <italic>0.997</italic> nM/L. This low power, all armchair g FET sensor with SAM ligands that may be chosen to bind different biomarkers provides a unique opportunity for high throughput, real time, low cost, high mobility, and minimal calibration sensing applications.
author_names: Andres Jaramillo-Botero

Juan M Marmolejo-Tejada
title: All Armchair Graphene Nanoribbon Field Effect Uridine Diphosphate Glucose Sensor: First Principles In Silico Design and Characterization
venue: IEEE Sensors Journal
year: 2019

abstract: Three dimensional (3D) carbon aerogels with well defined structures, e.g. high specific surface area (SSA) appropriate pore size distribution, good electrical conductivity and ideal building blocks have been regarded as promising electrode materials or substrates for incorporated with pseudocapacitive materials for energy storage and conversion applications. Herein, we report a simple and scalable sonochemical method followed by chemical activation process to transform bacterial cellulose derived carbon nanofiber aerogels (CNFAs) into 3D graphene nanoribbon aerogels (GNRAs) for supercapacitors. Benefits from its high SSA, reasonable pore size distribution and good conductivity, the GNRAs electrodes demonstrate a long cyclability, good rate capability and high charge storage performance for supercapacitors, which yields more than 1.5 times (three electrode system) and 2.6 times (two electrode system) of gravimetric capacitance compared to the CNFAs electrode. In addition, a hybrid Ni Co layered double hydroxides (LDHs)@GNRAs electrode achieves an impressive gravimetric capacitance of 968 F g 1 (based on the mass of the active material) at a current density of 1 A g 1. Moreover, an asymmetric supercapacitors (ASCs) device with a remarkable energy density of 29.87 Wh kg 1, wide working voltage windows of 1.6 V and good cycling stability (63.5% retention after 10,000 cycles) is achieved by using the GNRAs as anode and the Ni Co LDHs@GNRAs as cathode.
author_names: Liujun Cao

Lifei Liu

Xuejing Chen

Man Huang

Xue Wang

Jianping Long
title: Scalable syntheses of three dimensional graphene nanoribbon aerogels from bacterial cellulose for supercapacitors.
venue: Nanotechnology
year: 2019