Effect of particle size on the optical properties of silicon-vacancy centers in nanodiamonds fabricated by a detonation process

Nanodiamonds containing silicon-vacancy centers (SiV-NDs) are attracting attention as promising fluorescent markers. Recently, the preparation of single-digit-nanometer-sized SiV-NDs by a detonation process, which can be carried out on a practical scale, has been demonstrated. However, little is known about the effect of these extremely small diamonds fabricated by a detonation process on the electronic state of the SiV centers. In the present study, SiV-NDs prepared by the detonation process are investigated spectroscopically. It is reported that the extremely small particle size, ≈10 nm, causes an increase of the nonradiative transition probability and an enhancement of the electron–phonon coupling compared with those of typical SiV centers. Because of their electronic states, SiV-NDs also exhibit a short luminescence lifetime (≈0.56 ns) and a large linewidth (≈14.4 nm) at room temperature. Nevertheless, the fundamental properties of the SiV center, such as the photostability, do not change, irrespective of the particle size. (© 2022 DAICEL Corporation. physica status solidi (a) applications and materials science published by Wiley‐VCH GmbH)