High-Pressure Synthesis of Nanodiamonds from Adamantane Myth or Reality?
Résumé
The high-pressure and high-temperature technique is the most promising for mass production of ultra-small diamond nanoparticles of perfect structure. In the present work, this technique was successfully used for the synthesis of nanodiamonds from their molecular analogue, adamantane. A minimum size of synthesized diamond crystals of about 3nm was reached. It was found that the decisive condition for the stable production of nanodiamonds from adamantane under pressures below the limit value required for direct conversion of graphite into diamond is the minimization of the carbon sample loss during the synthesis. The possibility of doping such diamonds with optically active impurities is demonstrated by the synthesis of submicron diamonds, containing nitrogen-related centers, from a mixture of adamantane and adamantane carbonitrile.