From more efficient catalysts to longer-lasting electronic devices, many modern technologies rely on materials that must perform reliably at the nanoscale, often under extreme conditions. Yet predicting how these tiny crystals behave under stress remains a major challenge.

When subjected to high pressure, nanocrystals become ideal testbeds, revealing how materials bend, where defects first appear and what drives structural transformations. “Nanocrystals don’t behave like bulk materials because their mechanical response can be dramatically different, with direct consequences for performance and durability in real-world applications”, explains Abdelrahman Zakaria, researcher at the Aix-Marseille University and corresponding author of the publication.

Now Zakaria, in collaboration with the ESRF, has used the technique of BCDI inside a diamond anvil cell on beamline ID27. They tracked the 3D strain and defects in individual platinum nanoparticles using high-energy X-rays.

 “Until now, applying BCDI under such conditions had been extremely challenging. This is why we joined forces with scientists from beamline ID01, which specializes in this technique, with ID27, where the team specializes in high pressure and this has led to the success of this experiment”, says Zakaria.

The team found that at lower pressures (up to about 2.7 GPa), the nanoparticle behaved elastically, maintaining its structure aside from a stable defect at the interface with its substrate. As pressure increased to around 5 GPa, the researchers observed a sharp transition: a dense network of dislocations formed, marking the onset of plastic deformation.

These defects evolved into loops and complex structures, revealing how the crystal reorganises internally to accommodate stress.

Reversible defects

When the pressure was partially released, the original defect reappeared, showing that some changes are reversible even at the nanoscale. In some cases, the defect transformed into a mobile dislocation that moved through the crystal via a mechanism known as cross-slip. Unexpectedly, new defects formed in regions of high surface strain rather than near the substrate interface, challenging existing models of where deformation should begin.

This study demonstrates the feasibility of performing BCDI at the ID27 beamline opening new possibilities to probe nanomaterials under extreme conditions such as high pressure. This research is primarily fundamental, as it aims to uncover the mechanisms of deformation and defect formation at the nanoscale under extreme conditions, phenomena that are still not fully understood. It also has implications for applications. By understanding where and how defects form and evolve, scientists can better design nanomaterials with improved mechanical stability and performance. This could ultimately help tune catalysts (activity and durability), enhance the reliability of electronic components, and improve materials used in energy systems (for example, under high stress or harsh environments).

Reference:

Zakaria A., et al, Nano Letters 2026 26 (14), 4807-4814

DOI: 10.1021/acs.nanolett.6c00462

Text by Montserrat Capellas Espuny