This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Nanodiamonds are tiny diamond particles that usually measure mere millionths of a millimeter. They are extremely hard, stable and heat-resistant and highly adaptable for various purposes in medicine, new materials, catalysis and energy technology.
By compressing plastic with lasers, researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and the University of Rostock are now able to systematically produce high-purity, ultra-small diamonds with a narrow size distribution. This is impossible to achieve with conventional methods such as explosions. As a scalable technology, laser compression offers great potential for improved, clean and sustainable production of ultra-small nanodiamonds.
When the researchers first created nanodiamonds using laser compression, their initial focus was on planetary physics. They fired high-power lasers at plastics, heating and compressing the material to simulate the extreme conditions inside planets such as Neptune or Uranus, where temperatures reach several thousand degrees Celsius under pressures that are millions of times higher than in Earth's atmosphere—ideal conditions for transforming carbon into diamonds. The study is published in the journal Diamond and Related Materials.
"We did expect nanodiamonds to form under these conditions. What surprised us, however, was how quickly it happened, which immediately sparked the idea of a potential technical application," says Dominik Kraus, founding director of the new HEDI—Institute of High Energy Density Physics at HZDR and professor at the University of Rostock. At the time, however, the scientists could only briefly demonstrate the formation of diamonds under these extreme conditions.
Whether they would survive a transition to normal pressure and temperatures has now been successfully demonstrated. The experiments took place at the beamlines of the Extreme Light Infrastructure (ELI) south of Prague, a unique laser facility with a high repetition rate at very high energies. Three times per minute, the high-power laser at the L4n-P3 facility fires light pulses at a 100-micrometer-thin PET film, which is raster-scanned by the beam.
Nanodiamonds form inside the shock wave and are then ejected from the film like projectiles and collected in a cylinder containing a catcher substance. Kraus describes the challenge as follows: "When the compression wave reaches the end of the sample, it abruptly enters a vacuum, accelerating the nanodiamonds to speeds of more than 10 kilometers per second—comparable to a meteorite impact. To prevent the diamonds from immediate destruction upon impact with the collection cylinder, we need to use a very soft collection medium." The researchers chose a vacuum-compatible, water-soluble ionic gel.
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