Scientists are always looking for new ways to create artificial diamonds. A recent breakthrough by a team at the University of Tokyo offers a fresh perspective. They found a method that not only encourages diamond formation but also protects organic materials from damage typically caused by electron beams. This could lead to improved imaging and analysis techniques.
Traditionally, making diamonds requires extreme conditions—high pressure and high temperature. Another common method is chemical vapor deposition, which isn’t stable. In contrast, Professor Eiichi Nakamura and his team introduced a low-pressure technique that utilizes electron irradiation on a carbon molecule called adamantane.
Adamantane is particularly interesting because its structure closely resembles that of diamond. Both have a symmetrical arrangement of carbon atoms. However, to convert adamantane into diamond, specific bonds need to be broken and reformed. This challenge had many believing it was impossible.
“No one thought it was feasible,” Nakamura said, reflecting on the skepticism in the field.
Interestingly, mass spectrometry has shown that single-electron ionization can help break these bonds, but it only provides insights into gas-phase reactions and can’t isolate products from intermolecular interactions.
To overcome these limitations, the team used transmission electron microscopy (TEM) to watch what happens when solid adamantane is bombarded with electrons. They irradiated tiny crystals at various temperatures and voltages. This approach not only revealed how nanodiamonds form but also suggested that TEM could be used more widely to study organic molecules.
Nakamura, who has worked in synthetic chemistry for decades, viewed this as a critical breakthrough. “I wanted to see the reactions happening,” he explained, eagerly contrasting his work with the previous belief that electron beams destroy organic materials. He has devoted years to demonstrating the opposite.
The process led to the generation of pure nanodiamonds, each about 10 nanometers wide, along with hydrogen gas. Time-lapse images captured the transformation of adamantane into spherical nanodiamonds, showcasing a controlled reaction process. When tested with other hydrocarbons, only adamantane produced successful results, confirming its effectiveness.
This discovery carries implications beyond just diamond synthesis. It could reshape our understanding of chemistry in fields like electron lithography and surface engineering. Furthermore, it supports existing theories that diamonds can form in extreme environments, such as meteorite impacts or nuclear processes, driven by high-energy particles.
Nakamura’s findings may also pave the way for creating specialized quantum dots necessary for advanced technology like quantum computers and sensors. “This synthesis shows that electrons can facilitate controlled chemical reactions if we prepare the molecules correctly,” he said, sharing his vision of revolutionizing research through these insights.
For more on the study, see “Rapid, low-temperature nanodiamond formation by electron-beam activation of adamantane C–H bonds” by Jiarui Fu and colleagues, published in Science. [Read the full article here](https://doi.org/10.1126/science.adw2025).
Source link
Diamonds,Materials Science,Nanotechnology,University of Tokyo
