Bottom-up Synthesis of Molecular and Fluorescent Nanodiamonds from Nanographene

Nanodiamonds with colour centres have the potential to transform a wide range of disciplines, including quantum computation1,2, surface NMR spectroscopy3–6, single-spin magnetometry7,8, widefield quantum microscopy9, and single photon sources10,11. However, the controlled synthesis of ultra-small and uniform molecular ND (m-NDs) still represents a great challenge. The synthesis techniques currently available only allow for the production of NDs that vary in terms of their particle size distribution, morphology, the presence of undesired contaminants and lattice defects leading to inconsistent fluorescence properties. This greatly limits the performance and applications of NDs. Herein, molecularly defined nanographenes have been used for the first time as precursors for the high-pressure, high-temperature synthesis of nanodiamonds. Superphenalene has been discovered for the bottom-up synthesis of ultra-small, monodisperse nanodiamonds without impurities and on a milligram scale. It also provides a simple and efficient platform for introducing atomic colour centres into the nanodiamond lattice based on a two-component mixture. Fluorescent nanodiamonds with silicon or germanium related color centres are obtained without impurities and without the need for post-synthesis activation of colour centres. Nanographenes thus establish a new paradigm for the large-scale production of high quality molecular nanodiamonds and the introduction of colour centres, which will offer great prospects for future applications of nanodiamonds.