Monodispersed Nanodiamonds Produced by Laser Ablation

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Monodispersed Nanodiamonds Produced by Laser Ablation Boris Zousman and Olga Levinson Ray Techniques Ltd 4-2, High-Tech village, The Hebrew University of Jerusalem, P.O.B. 39162, 91391, Israel Abstract Nanodiamond powder (ND) has become one of the most promising and well-studied nanomaterials applied in various fields of science, technology and medicine. Recent achievements in the development of advanced ND applications present new demands to ND quality: purity, homogeneity of primary particle dimensions and surface area chemistry. ND produced by state-ofthe-art technology of detonation synthesis doesn’t meet requirements for biomedical and optical applications. Therefore, alternative methods of ND synthesis from pure carbon raw materials enabling to control the process are of especial importance. The novel technology for ND laser synthesis has been developed by Ray Techniques Ltd. The method is based on high-intensive laser radiation treatment of the specially prepared target containing non-diamond carbon soot and hydrocarbons, placed in a liquid media. As a result, carbon atoms collect to form a cubic diamond crystalline lattice. To reach that, the appropriate parameters of the laser radiation, special composition of the target and the liquid media, as well as the treatment procedures were determined. The “winning” combination of these factors enables to obtain pure nanodiamonds (RayND). In contrast to the existing technology, the RT method is highly controllable, environment-friendly and efficient. RayND obtained under different conditions were studied and compared with detonation ND currently available at the market. It is proved that the higher level of purity and homogeneity of RayND constitutes significant advantages for most ND applications. Using RayND opens new frontiers in biomedicine (drug- and gene-delivery and bio-imaging agents), electronic industry (abrasives for wafer polishing, heat-conductive electrical-insulating compounds, CVD coatings, emitters, etc) and optics (displays, protective transparent films, laser lenses, optical windows and filters). Introduction ND belongs to the carbon nanomaterial family which, along with graphene, fullerene and nanotubes, has attracted great interest in recent years due to its unique physical and chemical properties [1, 2, 3]. First ND applications were rooted in defense industry but now have reached into a variety of fields such as fine polishing, lubricating, coatings and polymers. In recent years ND rapidly enter bio-medicine, Thermal Management in electronics, photovoltaic and energy storage applications. ND is composed of nano-crystalline diamond particles with average size of 4-5 nm usually collected in aggregates of a few hundred nm and even microns. ND primary particle has all the unique properties of “big” diamond offering also some additional advantages. Each ND particle is “enveloped” by a chemically active shell of functional groups with unpaired electrons [1]. Properly created (modified) active shell enables covalent bonding with molecules of various