NV-centers in nanodiamonds: How good they are

This paper presents a method for determination of the size distribution for diamond nanocrystals containing luminescent nitrogen-vacancy (NV) centers using the luminescence intensity only. We also revise the basic photo physical properties of NV centers and conclude that the luminescence quantum yield of such centers is significantly smaller than the frequently stated 100%. The yield can be as low as 5% for centers embedded in nanocrystals and depends on their shape and the refractive index of the surrounding medium. The paper also addresses the value of the absorption cross-section of NV centers. [Display omitted] •Luminescence quantum yield of nitrogen-vacancy (NV) centers in 30–70nm crystals is ~0.05–0.2, smaller than thought•Absorption cross-section of NV-centers is typically about 2 times smaller in nano-crystals than in bulk diamond•Diamonds 40–150nm across have approximately size independent concentration of NV-centers and this can be used for sizing