Mixed sp2–sp3 Nanocarbon Materials: A Status Quo Review

Carbon nanomaterials with a different character of the chemical bond—graphene (sp2) and nanodiamond (sp3)—are the building bricks for a new class of all-carbon hybrid nanomaterials, where the two different carbon networks with sp3 and sp2 hybridization coexist, interacting and even transforming into one another. The extraordinary physiochemical properties defined by the unique electronic band structure of the two border nanoallotropes ensure the immense application potential and versatility of these all-carbon nanomaterials. The review summarizes the status quo of sp2 – sp3 nanomaterials, including graphene/graphene-oxide—nanodiamond composites and hybrids, graphene/graphene-oxide—diamond heterojunctions, and other sp2–sp3 nanocarbon hybrids for sensing, electronic, and other emergent applications. Novel sp2–sp3 transitional nanocarbon phases and architectures are also discussed. Furthermore, the two-way sp2 (graphene) to sp3 (diamond surface and nanodiamond) transformations at the nanoscale, essential for innovative fabrication, and stability and chemical reactivity assessment are discussed based on extensive theoretical, computational and experimental studies.

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Synthesis and structural characterization of Ca12Ga14O33

Scientific Reports ◽

10.1038/s41598-020-73311-w ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Sabrina E. A. McCoy ◽

John R. Salasin ◽

S. Michelle Everett ◽

Claudia J. Rawn

Keyword(s):

Powder Diffraction ◽

Structural Model ◽

Electronic Band Structure ◽

Rietveld Method ◽

Experimental Studies ◽

Phase Evolution ◽

Neutron Powder Diffraction ◽

Electronic Band ◽

Wet Chemistry ◽

X Ray

Abstract Ca12Ga14O33 was successfully synthesized using a wet chemistry technique to promote the homogenous mixing of the Ca and Ga cations. Rietveld refinements on X-ray and neutron powder diffraction data confirm that the compound is isostructural to Ca12Al14O33, however, with a significantly larger lattice parameter allowing for the cages that result from the framework arrangement to expand. In naturally occurring Ca12Al14O33, the mineral mayenite, these cages are occupied by O2− anions, however, experimental studies exchanging the O2− anions with other anions has led to a host of applications, depending on the caged anion. The functional nature of the structure, where framework distortions coupled with cage occupants, are correlated to electronic band structure and modifications to the framework could lead to interesting physical properties. The phase evolution was tracked using thermogravimetric analysis and high temperature X-ray diffraction and showed a lower formation temperature for the Ca12Ga14O33 analogue compared to Ca12Al14O33 synthesized using the same wet chemistry technique. Analyzing both X-ray and neutron powder diffraction using the Rietveld method with two different starting models results in one structural model, with one Ca position and the caged O on a 24d special position, being preferred.

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Theoretical and experimental studies of electronic band structure for GaSb1−xBix in the dilute Bi regime

Journal of Physics D Applied Physics ◽

10.1088/0022-3727/47/35/355107 ◽

2014 ◽

Vol 47 (35) ◽

pp. 355107 ◽

Cited By ~ 35

Author(s):

M P Polak ◽

P Scharoch ◽

R Kudrawiec ◽

J Kopaczek ◽

M J Winiarski ◽

...

Keyword(s):

Band Structure ◽

Electronic Band Structure ◽

Experimental Studies ◽

Electronic Band

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First-principles study of electronic, dynamical and thermodynamic properties of γ-Li4SiO4

International Journal of Modern Physics B ◽

10.1142/s0217979215501283 ◽

2015 ◽

Vol 29 (18) ◽

pp. 1550128 ◽

Cited By ~ 2

Author(s):

Qiushi Guan ◽

Tao Gao ◽

Yanhong Shen ◽

Shenggui Ma ◽

Tiecheng Lu ◽

...

Keyword(s):

Density Functional ◽

Phonon Dispersion ◽

Electronic Band Structure ◽

Dynamic Properties ◽

Experimental Studies ◽

High Symmetry ◽

Generalized Gradient ◽

Electronic Band ◽

Specific Heats ◽

Indirect Band Gap

We have studied the structural, electronic and dynamic properties of γ- Li4SiO4(lithium orthosilicate) using density functional theory (DFT) with the generalized gradient approximation (GGA). The crystal structure is fully relaxed. The electronic band structure and Density of States (DOS) calculations indicate that γ- Li4SiO4is an insulator with an indirect band gap of 5.19 eV and it has a conduction band with the width of 5.92 eV and two valance bands with the width of 4.45 eV and 0.57 eV, respectively. In the partial DOS, Li and Si electronic densities increase more sharply than O atoms. Comparing with previous works, the phonon dispersion curves without negative frequencies are calculated along high symmetry points. By adding the Born effective charges in the phonon calculation, the LO–TO splittings are also calculated which indicate that γ- Li4SiO4is polar and anisotropic. The optical modes of phonon frequencies at Γ point are assigned as Raman and Infrared-active modes. Additionally, the thermodynamic functions (entropy, internal energy, Helmholtz free energies and constant-volume specific heats) were determined by using the phonon DOS. The calculated results may provide useful guidance of γ- Li4SiO4for future experimental studies in some degree.

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First-principles investigation of structural, electronic, optical and dynamical properties in CsAu

Open Physics ◽

10.2478/s11534-011-0036-1 ◽

2011 ◽

Vol 9 (5) ◽

Cited By ~ 1

Author(s):

Bahattin Erdinc ◽

Fethi Soyalp ◽

Harun Akkus

Keyword(s):

Bulk Modulus ◽

Density Functional ◽

Electronic Band Structure ◽

Theoretical Calculations ◽

Experimental Studies ◽

Generalized Gradient ◽

Pressure Derivative ◽

Electronic Band ◽

Dynamical Properties ◽

Energy Dependent

AbstractThe structural, electronic, optical and dynamical properties of CsAu compound in the CsCl(B2) phase were investigated using the density functional theory (DFT) within the generalized gradient approximation (GGA). The calculated lattice constant, static bulk modulus and first-order pressure derivative of the bulk modulus are reported and compared with previous experimental and theoretical calculations. The calculated electronic band structure for this compound is in good agreement with available theoretical and experimental studies. The present band calculation indicates that CsAu compound has an indirect gap at R→X points. Furthermore, the linear photon-energy-dependent dielectric functions have been calculated. For the first time, the electronic structure results are used, within the implementation of a linear-response technique, for calculations of phonon properties.

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Experimental methods in entrepreneurship research: the status quo

International Journal of Entrepreneurial Behaviour & Research ◽

10.1108/ijebr-05-2016-0135 ◽

2016 ◽

Vol 22 (6) ◽

pp. 958-983 ◽

Cited By ~ 25

Author(s):

Sascha Kraus ◽

Fabian Meier ◽

Thomas Niemand

Keyword(s):

Design Methodology ◽

Experimental Studies ◽

Experimental Methods ◽

Status Quo ◽

Future Directions ◽

Content Type ◽

Entrepreneurship Research ◽

Research Areas ◽

The Status ◽

Insight Into

Purpose The purpose of this paper is to evaluate the emerging field of experimental research on entrepreneurship to better understand its development and potential. Design/methodology/approach A systematic, evidence-based literature review was applied, resulting in a sample of 47 articles having used experiments in entrepreneurship research so far. The papers are analyzed according to their topic, methods, and research design, revealing insight into their limitations and prospective contributions. Findings The paper discusses the potential and disadvantages of experimental methods while arguing for experiments as the method of choice for answering causality questions. This study finds a persistent increase in experimental entrepreneurship research since its introduction in 1990. Research limitations/implications The study provides research from the field of entrepreneurship with future directions, with potential research areas and an orientation for those interested in conducting experiments. Originality/value Experiments are employed in a variety of research areas and have become more and more popular in the field of entrepreneurship. No study has analyzed the experimental studies in entrepreneurship. This paper contributes by providing an overview of the field, reflecting and discussing the outcomes while characterizing the methods employed.

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Graphene – Diamond Nanomaterials: A Status Quo Review

10.20944/preprints202107.0647.v1 ◽

2021 ◽

Author(s):

Jana Vejpravová

Keyword(s):

Carbon Nanomaterials ◽

Chemical Reactivity ◽

Experimental Studies ◽

Chemical Properties ◽

Electronic Energy ◽

New Class ◽

Current State ◽

Carbon Networks ◽

Application Potential ◽

And Chemical Properties

Carbon nanomaterials with a different character of the chemical bond – graphene (sp2) and nanodiamond (sp3) are the building bricks for a new class of all-carbon hybrid nanomaterials, where the two different carbon networks with the sp3 and sp2 hybridization coexist, interact and even transform into one another. The unique electronic, mechanical, and chemical properties of the two border nanoallotropes of carbon ensure the immense application potential and versatility of these all-carbon graphene – diamond nanomaterials. The review gives an overview of the current state of the art of graphene – diamond nanomaterials, including their composites, heterojunctions, and other hybrids for sensing, electronic, energy storage, and other applications. Also, the graphene-to-diamond and diamond-to-graphene transformations at the nanoscale, essential for innovative fabrication, and stability and chemical reactivity assessment are discussed based on extensive theoretical, computational, and experimental studies.

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