Bulk composite of silica and detonation nanodiamonds with partially removed sp2 shells

Ceramics International. 2025. Vol. 51. No. 18. P. 25160–25168.

V.E. Antonov

Diamonds with impurity-vacancy centers are an attractive material for microphotonics and can be used, for example, as single photon emitters. Detonation nanodiamonds (DNDs) with intrinsic single nitrogen-vacancy (NV) centers are cheap and suitable for mass production. This paper proposes a way to overcome the two main properties of the DNDs: the tendency to agglomeration and the presence of a thick shell of sp2-hybridized carbon around each detonation nanodiamond particle. It is shown that SiO2 aerogel with uniformly distributed single diamond nanocrystals compressed to 7.5 GPa at 250 ◦C irreversibly transforms into a dense and chemically inert material. Subsequent treatment of this material in a hydrogen atmosphere at 7.5 GPa and 600 ◦C passivates dangling bonds in the silica matrix and eliminates its parasitic luminescence. The hydrogenation also largely removes the sp2 shells from DNDs and converts their neutral NV0 centers into more useable negatively charged NV􀀀centers. After each stage of preparing the dense DNDs/SiO2 composite, the material was examined by X-ray diffraction and Infrared and Raman spectroscopy.

Keywords: pressing, прессование, silicon dioxide, диоксид кремния, композиты, composites, детонационные наноалмазы, Detonation nanodiamonds