Related Experiment Video
Updated: Mar 2, 2026
14:52
Fabrication of Three-Dimensional Graphene-Based Polyhedrons via Origami-Like Self-Folding
Published on: September 23, 2018
9.4K
Raman Radial Mode Revealed from Curved Graphene
Jae-Kap Lee1, K P S S Hembram1, Yeseul Park1,2
1Optoelectronic Materials and Devices Research Center, Korea Institute of Science and Technology , Seoul 130-650, Republic of Korea.
The Journal of Physical Chemistry Letters
|May 19, 2017
Summary
A new Raman spectroscopy method distinguishes graphene layers by analyzing low-energy signals (100–500 cm-1). This technique identifies nanocurvature in monolayer and bilayer graphene, offering a standard for evaluating graphene structures.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Distinguishing the number of layers in graphene structures is a fundamental challenge.
- Current methods for graphene characterization may lack simplicity or universality.
Purpose of the Study:
- To develop a straightforward methodology for identifying and evaluating graphene layers.
- To correlate low-energy Raman signals with specific graphene structural properties.
Main Methods:
- Utilizing Raman spectroscopy to analyze signals in the 100–500 cm-1 range.
- Employing Raman simulations based on Raman radial mode (RM) Eigen vectors.
- Correlating specific Raman peaks (118 cm-1, 175 cm-1) with graphene nanocurvature.
Main Results:
- Identified distinct Raman peaks at 118 cm-1 and 175 cm-1 associated with graphene nanocurvature.
- Demonstrated that the 175 cm-1 signal corresponds to monolayer graphene (nanocurvature ≈ 1 nm).
- Showed that the 118 cm-1 peak is indicative of bilayer graphene (nanocurvature ≈ 2 nm).
Conclusions:
- The proposed Raman spectroscopy method provides a simple and effective way to discern graphene layers.
- The Raman radial mode model offers a standardized approach for evaluating graphene structures.
- Low-energy Raman signals are directly linked to the nanocurvature of graphene sheets.
Related Concept Videos
01:20Raman Spectroscopy: Overview
2.0K
The underlying principle of Raman spectroscopy is based on the interaction between light and matter, specifically molecules' inelastic scattering of photons. When a monochromatic beam of light, typically from a laser source, interacts with a sample, most scattered light has the same frequency as the incident light. This is known as Rayleigh scattering.
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and...
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and...
2.0K
01:07Radicals: Electronic Structure and Geometry
5.3K
This lesson delves into the geometry of a radical, which is influenced by the electronic structure of the molecule. The principle is similar to that of a lone pair, where the unpaired electron influences the geometry at the radical center.
Accordingly, the structure of a trivalent radical lies between the geometries of carbocations and carbanions. An sp2-hybridized carbocation is trigonal planar, while an sp3-hybridized carbanion is trigonal pyramidal. Here, the difference in geometry is...
Accordingly, the structure of a trivalent radical lies between the geometries of carbocations and carbanions. An sp2-hybridized carbocation is trigonal planar, while an sp3-hybridized carbanion is trigonal pyramidal. Here, the difference in geometry is...
5.3K
01:18Unsymmetric Bending
898
Unsymmetrical bending occurs when the bending moment applied to a structural member does not align with its principal axis. This misalignment leads to complex stress distributions and deflection patterns that differ from those in symmetrical bending, and are essential for designing structures to withstand different loading conditions. In unsymmetrical bending, the neutral axis—where stress is zero—does not necessarily align with the geometric axes of the cross-section. The...
898
01:17Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals
3.6K
Ideally, an unpaired electron shows a single peak in the EPR spectrum due to the transition between the two spin energy states. However, coupling interactions can occur between the spins of the unpaired electron and any neighboring spin-active nuclei. This hyperfine coupling results in hyperfine splitting, where the EPR signal is split into multiplets. The signals split into 2nI + 1 peaks, where n is the number of equivalent nuclei and I is the nuclear spin. These splitting patterns provide...
3.6K
01:18Deformations in a Symmetric Member in Bending
557
When analyzing the deformation of a symmetric prismatic member subjected to bending by equal and opposite couples, it becomes clear that as the member bends, the originally straight lines on its wider faces curve into circular arcs, with a constant radius centered at a point known as Point C. This phenomenon helps to understand the stress and strain distribution within the member more clearly.
When the member is segmented into tiny cubic elements, it is observed that the primary stress...
When the member is segmented into tiny cubic elements, it is observed that the primary stress...
557
01:27Gauss's Law: Planar Symmetry
9.7K
A planar symmetry of charge density is obtained when charges are uniformly spread over a large flat surface. In planar symmetry, all points in a plane parallel to the plane of charge are identical with respect to the charges. Suppose the plane of the charge distribution is the xy-plane, and the electric field at a space point P with coordinates (x, y, z) is to be determined. Since the charge density is the same at all (x, y) - coordinates in the z = 0 plane, by symmetry, the electric field at P...
9.7K