High yield fabrication of fluorescent nanodiamonds

Abstract

A new fabrication method to produce homogeneously fluorescent nanodiamonds with high yields is described. The powder obtained by high energy ball milling of fluorescent high pressure, high temperature diamond microcrystals was converted in a pure concentrated aqueous colloidal dispersion of highly crystalline ultrasmall nanoparticles with a mean size less than or equal to 10 nm. The whole fabrication yield of colloidal quasi-spherical nanodiamonds was several orders of magnitude higher than those previously reported starting from microdiamonds. The results open up avenues for the industrial cost-effective production of fluorescent nanodiamonds with well-controlled properties.

Observation and control of blinking nitrogen-vacancy centres in discrete nanodiamonds

“…3a). This result reproduced previous reports on NV luminescence in nanodiamonds 4,5,12,14 . However, in free space, discrete 5-nm nanodiamonds containing an NV centre revealed a new luminescence intermittency pattern, for which the effect of the nanodiamond surface state (as in the aggregated or polymer-embedded state) warrants further study.…”

“…1b), and their spectra (Fig. 1d) were consistent with those reported for NVs in nanodiamonds 6,14 . Furthermore, the second-order correlation function 1 g (2) (t) (see Methods) confirmed that the emission originated from a single centre (Fig.…”

“…Here, we use a robust deaggregation and dispersion method, which diminishes the crystal-crystal interaction to yield a quasi-isolated system of 'free-space' crystals weakly coupled to the underlying substrate. In contrast to other materials and processing techniques (such as milling 6,14 ), this method produces isolated detonation nanodiamonds with a well-defined size distribution on a dry substrate (see Methods). Figure 1 presents data from the analysed sample, collected with the combined confocal scanning fluorescence and atomic force microscope (AFM) system described previously 11 (a schematic is shown in Supplementary Fig.…”

“…For example, theoretical calculations of the crystal energy budget favour the location of nitrogen on the surface rather than in the core, which seems to explain the limited observation of NV centres in chemical vapour deposition and high-pressure high-temperature grains of less than 40 nm in size 11,12 , and favours the prediction that nanodiamonds smaller than 10 nm in size do not contain NV centres 7,13 . Although sub-10-nm nanodiamonds with NV centres have been produced using a top-down approach (milling luminescent high-pressure hightemperature microdiamonds into 7-nm particles 6,14 ), the question of NV stability in isolated detonation nanodiamonds persists.…”

Near-field microscopy with a single-photon point-like emitter: Resolution versus the aperture tip?

“…In the nanodiamond-based NSOM probe [9], the optical behavior originates from the point-like transition dipole associated with the radiative transition of the NV colorcenter. We here neglect the finite extension of the host nanocrystal since current trends in nanodiamond processing indicate that it can be diminished down to a few nms only [19,20]. Therefore, we expect the point-like model outlined above to apply to this tip and we will indeed describe the nanodiamond-based tip as a single point-like dipole.…”