Far-UV-excited luminescence of nitrogen-vacancy centers: Evidence for diamonds in space

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. Copyright © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.