Nanodiamonds are a type of carbon allotrope with the bonding structure of diamonds and sizes on the nanometer scale. Unlike other fluorescent carbon nanomaterials, the mechanism for emissions from nanodiamonds remained yet to be explored.

Guowei Yang and co-workers, Sun Yat-sen University, Guangzhou, China, identified the origin of nanodiamond fluorescence using various spectroscopic techniques, especially infrared microscopy. They found that diamond edges can hybridize with neighboring functional groups such as hydroxyl and ketone or ester carbonyl groups to enable emission, which is tunable by modifying surface groups.
These findings, while helping to understand the mechanism of nanodiamond fluorescence, and are also useful for designing nanodiamond-based materials with varied emission characteristics.

• Fluorescence Origin of Nanodiamonds,
  Jun Xiao, Pu Liu, Lihua Li, Guowei Yang,
  J. Phys. Chem. C 2015.
  DOI: 10.1021/jp512188x