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May 10, 2011

Nanocrystalline diamond aerogel produced from a carbon aerolgel and a laser heated diamond anvil

Scanning transmission X-raymicroscopy (STXM) analysis. (A) STXM image of a piece of diamond aerogel nonspecifically adhered to a copper TEM grid. Green line indicates direction of scan for data Scale bar: 1 micron. (B) Bright field TEM image and electron diffraction (inset) of a diamond aerogel following STXM analysis. Electron diffraction shows that nanocrystalline diamond rings are preserved following exposure to soft X-rays.

PNAS - Synthesis and characterization of a nanocrystalline diamond aerogel

Aerogel materials have myriad scientific and technological applications due to their large intrinsic surface areas and ultralow densities. However, creating a nanodiamond aerogel matrix has remained an outstanding and intriguing challenge. Here we report the high-pressure, high-temperature synthesis of a diamond aerogel from an amorphous carbon aerogel precursor using a laser-heated diamond anvil cell. Neon is used as a chemically inert, near-hydrostatic pressure medium that prevents collapse of the aerogel under pressure by conformally filling the aerogel’s void volume. Electron and X-ray spectromicroscopy confirm the aerogel morphology and composition of the nanodiamond matrix. Time-resolved photoluminescence measurements of recovered material reveal the formation of both nitrogen- and silicon- vacancy point-defects, suggesting a broad range of applications for this nanocrystalline diamond aerogel.

* The nanodiamond aerogel is 40 times as dense as air
* samples of the nanodiamond new gel are about 200 microns wide
* nanodiamond aerogel can be molded like plastic and is completely transparent
* Made of diamonds smaller than a quarter of the wavelength of violet light
* it does not react with many elements, therefore it is biocompatible
* nanodiamond aerogel can be used to coat structures in the human body
* It can coat glass or clear plastic to create tough but well-insulated windows and instruments for spacecraft
* Diamonds give off electrons, it can be used in ultra-light, ultra-tough quantum computers and other electronics
* it is reasonable to speculate that the chemical transformation from amorphous carbon to cubic nanocrystalline diamond could proceed through a hydrogen-catalyzed mechanism. However, detailed simulations are required to determine the precise atomistic processes involved in this phase transition.



6 pages of supplemental material




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