Presented by Abraham Wolcott,
Department of Chemistry, Columbia University
High-pressure, high-temperature (HPHT) nanodiamonds with nitrogen vacancy centers represent a unique class of fluorophores due to their long-lived electron spin properties, all-carbon matrix, and long-term photostability. While this class of nanodiamond has been used for long-term biolabeling, open questions concerning their surface, bulk and electronic properties hinder its full utilization as an active magnetometer in biological systems. In this study we demonstrate a level of crystallographic and electronic ordering in purified HPHT nanodiamonds that matches fundamental properties of bulk diamond to the nanoscale while retaining its fluorescing capability. In turn, this class of HPHT ND share few similarities with detonation nanodiamonds (DNDs). We discover fundamental differences between HPHT NDs and DNDs. We also show that the HPHT ND surface after oxidative purification consists largely of alcohols, which results in negatively charged nitrogen vacancy centers. These observations connect fundamental bulk, surface and color center properties of nanoscale diamond, providing new understanding that impacts their use across disciplines, from quantum computing to microscopy, sensing and biological applications.
