2, Adamas Nanotechnologies, Raleigh, North Carolina, United States
Detonation is a technique for manufacturing 5 nm diameter nanodiamonds, which are known as detonation nanodiamonds. Although these nanodiamonds are believed to have numerous NV centers, only a small fraction of them are optically active. As a result, the vast majority of detonation nanodiamond particles remain non-fluorescent for reasons that are not completely clear. On the other hand, bright and stable optically active NV fluorescent centers can be produced by irradiating microcrystalline diamonds that are synthesized by high pressure, high temperature (HPHT) processes. Reduction of size of these microcrystalline diamonds by milling yields brightly fluorescent NV nanodiamonds with the sizes down to 40 nm. However, milling of microcrystalline diamonds is a long and expensive process. Here, we investigate the possibility of producing smaller NV fluorescent nanodiamonds by mixing commercially available NV nanodiamonds with diameters ranging from 40 to 100 nm with explosives and detonating in the conditions typical for detonation nanodiamond synthesis. We purify and isolate the NV fluorescent nanodiamond nanoparticles, then determine their size and fluorescence after detonation. The behavior of NV fluorescent HPHT nanodiamonds in detonation environments and the potential to use detonation as a cheaper and faster way to reduce the size of NV fluorescent HPHT nanodiamonds below 40 nm will be discussed.