Nanodiamonds by Molecular Design

An international research team led by Dr Yingke Wu and Professor Tanja Weil at the Max Planck Institute for Polymer Research has now developed a new synthesis strategy: instead of breaking larger diamonds down into smaller particles, the team builds nanodiamonds from the bottom up using molecularly defined nanographene building blocks. Under high pressure and at high temperatures, these flat carbon molecules are directly converted into diamond-like, highly crystalline nanostructures.

The key advantage of this bottom-up approach lies in its control at the molecular level. Because the structure, size and composition of the starting molecules are precisely defined, the properties of the resulting nanodiamonds can be controlled much more effectively than with conventional milling or top-down methods. Using this strategy, the team was able to produce particularly small, uniform nanodiamonds measuring around three to four nanometres.

Another important aspect is that optically active colour centres can be incorporated into the diamond lattice directly during synthesis. By using suitable molecular precursors, silicon- and germanium-based emitters can be generated without the need for subsequent ion implantation, irradiation or further post-treatment. This makes it possible to produce fluorescent nanodiamonds with tailored optical properties in a single synthesis step.

“We believe this platform offers a scalable foundation for developing quantum sensors, integrated photonic emitters and programmable diamond-based nanomaterials,” says Tanja Weil.

The new molecular nanodiamonds open up promising opportunities for applications in quantum technology, for example as stable single-photon sources or nanoscale sensors. They are also of interest for biological and medical research: in the long term, they could serve as robust optical reporters to visualise processes in cells or other biological environments at the smallest scales.

The findings of the international team have been published in Nature.

Participating institutions

The study involved the German Electron Synchrotron (DESY), Goethe University Frankfurt, Johannes Gutenberg University Mainz, the Leibniz Institute for New Materials, the Max Planck Institute of Colloids and Interfaces, the Max Planck Institute for Polymer Research, the University of Cambridge, Saarland University, the University of Göttingen and Ulm University.