Biomod/2013/LMU/nanodiamonds: Difference between revisions
| Line 8: | Line 8: | ||
Nanodiamonds are allotropes (sp3) of carbon and possess a series of distinct properties compared to other carbon–based materials. Their outstanding characteristics include extreme hardness, high thermal conductivity, transparency at all optical wavelengths, biocompatibility, and chemical robustness <sup><cite>1</cite></sup>. Pure diamond is an electric insulator while doped diamond becomes a semiconductor with a large bandgap (5.5 eV at room temperature). Doped impurities additionally can create optically active defects – also called color centers – within the diamonds. If in particular two adjacent positions in the atomic lattice of a nanodiamond are replaced, one with nitrogen, the other with an empty space, a nitrogen–vacancy (NV) center is formed. Under excitation with appropriate light sources, such NV centers can act as reliable single-photon sources where the emitted photons carry defined spin information related to the spin state of the NV center. The widely used nanodiamonds production method was by detonation of TNT–hexogene mixtures and during the detonation process, nitrogen defects were introduced <sup><cite>2</cite></sup>.<br /> | Nanodiamonds are allotropes (sp3) of carbon and possess a series of distinct properties compared to other carbon–based materials. Their outstanding characteristics include extreme hardness, high thermal conductivity, transparency at all optical wavelengths, biocompatibility, and chemical robustness <sup><cite>1</cite></sup>. Pure diamond is an electric insulator while doped diamond becomes a semiconductor with a large bandgap (5.5 eV at room temperature). Doped impurities additionally can create optically active defects – also called color centers – within the diamonds. If in particular two adjacent positions in the atomic lattice of a nanodiamond are replaced, one with nitrogen, the other with an empty space, a nitrogen–vacancy (NV) center is formed. Under excitation with appropriate light sources, such NV centers can act as reliable single-photon sources where the emitted photons carry defined spin information related to the spin state of the NV center. The widely used nanodiamonds production method was by detonation of TNT–hexogene mixtures and during the detonation process, nitrogen defects were introduced <sup><cite>2</cite></sup>.<br /> | ||
Although nanodiamonds are sp3 allotrope of carbon materials, due to their high surface energy, many residual groups, such as hydroxyl, carboxyl, lactone, ketone, exist on nanodiamonds surface and these groups provided initial functional sites for further modification.<br /> | Although nanodiamonds are sp3 allotrope of carbon materials, due to their high surface energy, many residual groups, such as hydroxyl, carboxyl, lactone, ketone, exist on nanodiamonds surface and these groups provided initial functional sites for further modification.<br /> | ||
[[Image:NDsurface.png|thumb|border|250px|right|baseline|Functional groups of a Nanodiamonds, which was modified with wet method | [[Image:NDsurface.png|thumb|border|250px|right|baseline|Functional groups of a Nanodiamonds, which was modified with wet method]] | ||
The surface modification of the nanodiamonds can be divided in two main categories: wet methods <sup><cite>3 4</cite></sup> and dry methods <sup><cite>5 6</cite></sup>.The dry methods usually employ gas plasma or high temperatures to remove the surface impurities and embed functional radicals. The wet methods usually employ mineral acids to oxidize the surface and then further conjugate the oxidized surfaces with other groups by non-covalent or covalent interaction.<br /> | The surface modification of the nanodiamonds can be divided in two main categories: wet methods <sup><cite>3 4</cite></sup> and dry methods <sup><cite>5 6</cite></sup>.The dry methods usually employ gas plasma or high temperatures to remove the surface impurities and embed functional radicals. The wet methods usually employ mineral acids to oxidize the surface and then further conjugate the oxidized surfaces with other groups by non-covalent or covalent interaction.<br /> | ||
Both procedures modify the nanodiamonds surface by introducing carboxyl or amino groups to enable an attachment. For our project, we used nanodiamonds that were already modified with wet method by [http://www.uni-ulm.de/nawi/institut-fuer-organische-chemie-iii/prof-dr-tanja-weil.html Tanja Weil's group] from Ulm Univeristy. | Both procedures modify the nanodiamonds surface by introducing carboxyl or amino groups to enable an attachment. For our project, we used nanodiamonds that were already modified with wet method by [http://www.uni-ulm.de/nawi/institut-fuer-organische-chemie-iii/prof-dr-tanja-weil.html Tanja Weil's group] from Ulm Univeristy. | ||
Revision as of 15:43, 25 October 2013
<html>
<head>
<link href='http://fonts.googleapis.com/css?family=Open+Sans' rel='stylesheet' type='text/css'>
</head>
<style>
/*BUT ACTUALLY*/ body {
font-family: 'Open Sans', sans-serif; overflow-y: scroll;
}
.container {
background-color: #0000ff; margin-top:10px
} .OWWNBcpCurrentDateFilled { display: none; }
h5 {
font-family: 'Open Sans', sans-serif; font-size: 12px; font-style: normal; text-align: center; margin:0px; padding:0px;
}
- column-content
{
width: 5px; float: left; margin: 0 0 0 0; padding: 0;
} .firstHeading {
display:none; width:0px;
}
- column-one
{
display:none; width:0px; background-color: #ffffff;
}
- globalWrapper
{
width: 1000px; background-color: #ffffff; margin-left: auto; margin-right: auto
}
- content
{
margin: 0 0 0 0; align: center; padding: 12px 12px 12px 12px; width: 976px; background-color: #ffffff; border: 0;
}
- bodyContent
{
width: 950px; align: center; background-color: #ffffff;
}
- column-content
{
width: 1000px; background-color: #ffffff;
}
- footer
{
position: center; width: 1000px;
} @media screen {
body { background: #000000 0 0 no-repeat; /* changed default background */ }
}
- menu
{
position: fixed; float: left; width: 190px; padding: 5px; background-color: #FFFFFF; font-size: 15px; font-style: normal; text-align: left; margin:0px; padding:0px;
}
- pagecontent
{
float: right; width: 720px; margin-left: 300px; min-height: 500px
}
- toc { display: none; }
/*Expanding list*/ ul { list-style: disc; } ul.a { list-style: none; }
- exp li ul { display: none; }
- exp li:hover ul { display: block; }
- exp li a:active ul { display: block; }
a:link {color:#275ca8;} a:visited {color:#54c3f1;} /* visited link */ a:hover {color:#c2e5f8;} /* mouse over link */ a:active {color:#214897; } /* selected link */
</style> <body> </body> </html>
Properties of Nanodiamonds
Nanodiamonds are allotropes (sp3) of carbon and possess a series of distinct properties compared to other carbon–based materials. Their outstanding characteristics include extreme hardness, high thermal conductivity, transparency at all optical wavelengths, biocompatibility, and chemical robustness [1]. Pure diamond is an electric insulator while doped diamond becomes a semiconductor with a large bandgap (5.5 eV at room temperature). Doped impurities additionally can create optically active defects – also called color centers – within the diamonds. If in particular two adjacent positions in the atomic lattice of a nanodiamond are replaced, one with nitrogen, the other with an empty space, a nitrogen–vacancy (NV) center is formed. Under excitation with appropriate light sources, such NV centers can act as reliable single-photon sources where the emitted photons carry defined spin information related to the spin state of the NV center. The widely used nanodiamonds production method was by detonation of TNT–hexogene mixtures and during the detonation process, nitrogen defects were introduced [2].
Although nanodiamonds are sp3 allotrope of carbon materials, due to their high surface energy, many residual groups, such as hydroxyl, carboxyl, lactone, ketone, exist on nanodiamonds surface and these groups provided initial functional sites for further modification.
The surface modification of the nanodiamonds can be divided in two main categories: wet methods [3, 4] and dry methods [5, 6].The dry methods usually employ gas plasma or high temperatures to remove the surface impurities and embed functional radicals. The wet methods usually employ mineral acids to oxidize the surface and then further conjugate the oxidized surfaces with other groups by non-covalent or covalent interaction.
Both procedures modify the nanodiamonds surface by introducing carboxyl or amino groups to enable an attachment. For our project, we used nanodiamonds that were already modified with wet method by Tanja Weil's group from Ulm Univeristy.
References
-
Krueger, A. J.Mater. Chem. 2008, 18, 1485-1492
-
Osawa, E. Pure App. Chem. 2008, 80, 1365-1379
-
Ushizawa, K.; Sato, Y.; Mitsumori, T.; Machinami, T.; Ueda, T.; Ando, T. Chem. Phys. Lett. 2002, 351, 105-108
-
Kruger, A.; Liang, Y.; Jarre, G.; Stegk, J. J. Mater. Chem. 2006, 16, 2322-2328
-
Wenmackers, S.; Vermeeren, V.; vandeVen, M.; Ameloot, M.; Bijnens, N.; Haenen, K.; Michiels, L.; Wagner, P. Phys. Status Solidi A 2009, 206, 391-408
-
Takahashi, K.; Tanga, M.; Takai, O.; Okamura, H. Diam. Relat. Mater. 2003, 12, 572-576
