Far‐UV‐Excited Luminescence of Nitrogen‐Vacancy Centers: Evidence for Diamonds in Space

Abstract

The nitrogen-vacancy (NV) centers in diamond are among the most thoroughly investigated defects in solid-state matter; however, our understanding of their properties upon far-UV excitation of the host matrix is limited. This knowledge is crucial for the identification of NV as the carrier of extended red emission (ERE) bands detected in a wide range of astrophysical environments. Herein, we report a study on the photoluminescence spectra of NV-containing nanodiamonds excited with synchrotron radiation over the wavelength range of 125-350 nm. We observed, for the first time, an emission at 520-850 nm with a quantum yield greater than 20 %. Our results share multiple similarities with the ERE phenomena, suggesting that nanodiamonds are a common component of dust in space.

Nanodiamonds: Synthesis and Application in Sensing, Catalysis, and the Possible Connection with Some Processes Occurring in Space

“…Its compatibility with the zero phonon line of the NV − center in NDs is evidenced with a vertical line. A better, longer wavelength, PL-tail compatibility is expected under far-UV irradiation, as from Reference [132]. The peak at around 580 nm could be correlated with the NV 0 zero phonon line.…”

“…As can be seen, the ERE emission from the red rectangle (which is 25 times more intense than the other ERE nebular emissions, probably explaining why in all other lower signal strength spectra, they have not been resolved) is compatible with the photoluminescence spectrum of commercial uncoated Bikanta [131] 40 nm-tailed NDs, if the VIS (532 nm) pumping redshift with respect to far-UV pumping is taken into account, as was done in [131]. In particular, it is evident how the zero-phonon-line (ZPL) of the NVemission is present both in the ERE as well as in the crushed commercial NDs, thus suggesting a significant VIS pumping versus the far-UV pumping of the NDs causing the ERE emission from the red rectangle [128,132]. The peak at 637/638 nm is strongly reproducible and was first observed in [128].…”

Quantifying nanodiamonds biodistribution in whole cells with correlative iono-nanoscopy

“…But the released photons are unlikely to excite NV 0 and NV − directly since the absorption ranges of NV 0 and NV − are approximately 400−575 nm and 450−637 nm, respectively 24 . Notably, however, the energy released from this radiative recombination is sufficient to ionize the negatively charged defects, thereby converting NV − to NV 0 , similar to that of far-UV excitation 30 . And this could be evidenced by the weakened emission of NV − centers whose phonon sidebands are suppressed under -particle excitation, compared with the distinct phonon sidebands of NV 0 centers (Fig.…”

Nanodiamonds in Oil Emulsions as Effective Vaccine Adjuvants and Antitumor Therapeutic Agents

“…It should be emphasized here that the surface properties of these two types of particles (NDs and FNDs) are essentially identical to each other. They are surface-modi ed in the same manner (air oxidation and oxidative acid washes), except that the diamond powders used to prepare FNDs are pretreated with electron irradiation and vacuum annealing to create the color centers [35].…”

“…Nitrogen-vacancy centers in NDs were produced by radiation-damage of monocrystalline diamond powders (~100 nm in diameter) with a 10-MeV electron beam, followed by vacuum annealing at 800°C for 2 h, as previously described [35]. The as-produced FNDs were then treated by air-oxidation and strong acid washes as that of NDs, and nally conjugated with OVA by physical adsorption.…”