Del Mar Photonics - Newsletter Fall 2010 - Newsletter Winter 2010
 

Trestles CW/fs laser for spectroscopy of graphene and carbon nanotubes at Rice University - request a quote for Trestles Ti:Sapphire laser

Graphene is a one-atom-thick planar sheet of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice. The term Graphene was coined as a combination of graphite and the suffix -ene by Hanns-Peter Boehm,[1][2] who described single-layer carbon foils in 1962.[3] Graphene is most easily visualized as an atomic-scale chicken wire made of carbon atoms and their bonds. The crystalline or "flake" form of graphite consists of many graphene sheets stacked together.
The carbon-carbon bond length in graphene is about 0.142 nm. Graphene sheets stack to form graphite with an interplanar spacing of 0.335 nm, which means that a stack of 3 million sheets would be only one millimeter thick. Graphene is the basic structural element of some carbon allotropes including graphite, charcoal, carbon nanotubes, and fullerenes. It can also be considered as an indefinitely large aromatic molecule, the limiting case of the family of flat polycyclic aromatic hydrocarbons. The Nobel Prize in Physics for 2010 was awarded to Andre Geim and Konstantin Novoselov "for groundbreaking experiments regarding the two-dimensional material graphene".[4]

Graphene is a flat monolayer of carbon atoms tightly packed into a two-dimensional (2D) honeycomb lattice, and is a basic building block for graphitic materials of all other dimensionalities. It can be wrapped up into 0D fullerenes, rolled into 1D nanotubes or stacked into 3D graphite.[5]

References

[1] H. P. Boehm, R. Setton, E. Stumpp (1994). "Nomenclature and terminology of graphite intercalation compounds". Pure and Applied Chemistry 66 (9): 1893–1901. doi:10.1351/pac199466091893.
[2] H. C. Schniepp, J.-L. Li, M. J. McAllister, H. Sai, M. Herrera-Alonso, D. H. Adamson, R. K. Prud’homme, R. Car, D. A. Saville, I. A. Aksay (2006). "Functionalized Single Graphene Sheets Derived from Splitting Graphite Oxide". The Journal of Physical Chemistry B 110 (17): 8535–8539. doi:10.1021/jp060936f. PMID 16640401.
[3] H. P. Boehm, A. Clauss, G. O. Fischer, U. Hofmann (1962). "Das Adsorptionsverhalten sehr dünner Kohlenstoffolien". Zeitschrift für anorganische und allgemeine Chemie 316 (3-4): 119–127. doi:10.1002/zaac.19623160303.
[4] Nobel Foundation announcement
[5] Geim, A. K. and Novoselov, K. S. (2007). "The rise of graphene". Nature Materials 6 (3): 183–191. doi:10.1038/nmat1849. PMID 17330084.

 

Carbon nanotubes (CNTs; also known as buckytubes) are allotropes of carbon with a cylindrical nanostructure. Nanotubes have been constructed with length-to-diameter ratio of up to 132,000,000:1,[1] which is significantly larger than any other material. These cylindrical carbon molecules have novel properties which make them potentially useful in many applications in nanotechnology, electronics, optics, and other fields of materials science, as well as potential uses in architectural fields. They may also have applications in the construction of body armor. They exhibit extraordinary strength and unique electrical properties, and are efficient thermal conductors.
Nanotubes are members of the fullerene structural family, which also includes the spherical buckyballs. The ends of a nanotube may be capped with a hemisphere of the buckyball structure. Their name is derived from their size, since the diameter of a nanotube is on the order of a few nanometers (approximately 1/50,000th of the width of a human hair), while they can be up to 18 centimeters in length (as of 2010).[1] Nanotubes are categorized as single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs).
Chemical bonding in nanotubes is described by applied quantum chemistry, specifically, orbital hybridization. The chemical bonding of nanotubes is composed entirely of sp2 bonds, similar to those of graphite. These bonds, which are stronger than the sp3 bonds found in diamonds, provide nanotubules with their unique strength. Moreover, nanotubes naturally align themselves into "ropes" held together by Van der Waals forces.

[1] Wang, X.; Li, Q.; Xie, J.; Jin, Z.; Wang, J.; Li, Y.; Jiang, K.; Fan, S. (2009). "Fabrication of Ultralong and Electrically Uniform Single-Walled Carbon Nanotubes on Clean Substrates". Nano Letters 9 (9): 3137–3141. doi:10.1021/nl901260b. PMID 19650638.

 

 

 

Graphene nanoplatelets

Del Mar Photonics is involved in research of CNTs, graphene nanoplatelets and graphene materials, develops advanced multifunctional materials for variety of applications as well as research instrumentation for characterization of the above.

We currently we can offer:

1) Graphene nanoplatelets: the stack of multi-layer graphene sheets with high aspect ratio, diameter: 0.5-20 µm, thickness: 5-25 nm.
2) Graphene materials: Graphene Powder, Graphene Oxide Powder, Graphene Suspension.
3) Carbon Nanotubes.
 

Contact our application team to discuss your requirements for high-performance nanocomposite materials, display materials, sensing materials, ultracapacitors, batteries, energy storage and other area to improve electrical, thermal, barrier, or mechanical properties by using low-cost nano-additive.

Graphene nanoplatelets are the stack of multi-layer graphene sheets including platelet morphology, with characteristics as follows:

Physical Properties
Diameter Thickness Specific Surface Area Density Electrical Conductivity Tensile Strength
0.5 - 20 µm 5 - 25 nm 40-60 m2/g ~2.25 g/cm3 8000-10000 S/m 5 GPa

 

Bulk Characteristics
Appearance Carbon content Bulk density Water Content Residual impurities
A black and grey powder >99.5% ~0.30 g/ml <0.5 wt% <0.5 wt%

Request a quote for graphene nanoplatelets

Applications:

The high performance composite additives in PPO, POM, PPS, PC, ABS, PP, PE, PS, Nylon and rubbers.
To improve composite tensile strength, stiffness, corrosion resistance, abrasion resistance and anti-static and lubricant properties.
Mechanical properties modifications.
Conductivity modification.
Fuel tank coating.
In electronic enclosures add electrical conductivity to polymers at low densities of 3 to 5 wt%.
Adding EMI or RFI shielding capabilities to a variety of polymers.
Automotive parts: a composite with nanoplatelets can be painted electrostatically, thereby saving costs.
Aerospace: graphite has long been used in aerospace composites. Nanoplatelets can be combined with other additives to reinforce stiffness, add electrical conductivity, EMI shielding, etc.
Appliances: fortified polymers provide superior thermal and electrical conductivity, thereby saving the costs of separate heat dissipation mechanisms.
Sporting goods: graphite-based composites are stronger and stiffer and lighter than comparable materials.
Coatings and paints: graphene nanoplatelets can be dispersed in a wide variety of materials to add electrical conductivity and surface durability.
Batteries: graphene nanoplatelets increase the effectiveness of Lithium-ion batteries when used to formulate electrodes.
Fuel cells: both bi-polar plate and electrode efficiencies can be improved.

Del Mar Photonics develops advanced instrumentation for research of CNTs, graphene nanoplatelets and graphene materials including lasers for broadband spectroscopy, femtosecond transient absorption and fluorescence measurements.

T&D Scan high resolution Laser Spectrometer based on broadly tunable CW laser
CW single-frequency ring Dye laser
Beacon Femtosecond Optically Gated Fluorescence Kinetic Measurement System
New Hatteras femtosecond transient absorption system
Photon Scanning Tunneling Microscope

 

Del Mar Photonics, Inc.
4119 Twilight Ridge
San Diego, CA 92130
tel: (858) 876-3133
fax: (858) 630-2376
Skype: delmarphotonics
sales@dmphotonics.com

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