Direct synthesis of group IV-vacancy center-containing nanodiamonds via detonation process using aromatic compound as group IV element source

Nanodiamonds (NDs) containing group IV-vacancy (G4V) centers-silicon-vacancy (SiV), germanium-vacancy (GeV) and tin-vacancy (SnV) centers-have shown promising potential as fluorescent markers for bioimaging and -sensing. However, the scale of fabrication has been limited to the laboratory scale. In this study, a detonation process was applied that enables practical scale fabrication of NDs for the direct synthesis of these G4V center-containing NDs (G4V-NDs). This detonation process for the direct synthesis of G4V-NDs employed explosives with the addition of dopant molecules with group IV atoms centered on tetraphenyl compounds. The successful synthesis of negatively charged SiV and GeV center-containing NDs (SiV- and GeV-NDs) was evidenced by photoluminescence (PL) spectra with zero-phonon lines (ZPLs) attributed to such color centers. However, as a result of the same strategy, NDs containing the SnV centers were not obtained in detectable concentrations in PL measurements. When the generated concentrations of SiV- and GeV-NDs synthesized under identical conditions were evaluated based on the number of data points that clear ZPLs were observed on the PL mappings, the SiVNDs were found to be produced more predominantly than the GeV-NDs. The physics behind such results is explained by the difference in the reaction thermodynamics for each group IV atom.

Automated summary

In this study, a detonation process was used to fabricate nanodiamonds containing group IV-vacancy (G4V) centers. The synthesis of silicon-vacancy (SiV) and germanium-vacancy (GeV) center-containing nanodiamonds was successful, while tin-vacancy (SnV) center-containing nanodiamonds were not obtained in detectable concentrations. The results suggest that the reaction thermodynamics for each group IV atom play a role in the synthesis.