Scientists at the University of Tokyo have developed a groundbreaking method for synthesizing diamonds that eliminates the need for the intense heat and pressure traditionally required.
The team, led by Professor Eiichi Nakamura, discovered that exposing specific carbon compounds to an electron beam could convert them into diamond structures while preserving their delicate molecular frameworks. This breakthrough holds promise for safer, more efficient analytical techniques in materials science and biology.
Conventionally, diamonds are created either by compressing carbon at extremely high temperatures and pressures or through gas-phase chemical vapor deposition — both resource-intensive processes. In contrast, the Tokyo team’s technique uses controlled electron irradiation on a carbon-based molecule known as adamantane (C₁₀H₁₆).
The process involves removing hydrogen atoms (C–H bonds) from adamantane and replacing them with carbon–carbon (C–C) linkages, forming a three-dimensional diamond lattice.
Using transmission electron microscopy (TEM), the researchers directed 80–200 kiloelectron-volt electron beams at tiny adamantane crystals in a vacuum at temperatures between 100 and 296 kelvins for a few seconds. This precise setup enabled the formation of nanodiamonds—up to 10 nanometers in diameter—with a cubic crystal structure.
Time-resolved TEM imaging revealed the gradual transformation of adamantane chains into spherical nanodiamonds. The team found that the reaction rate depended on the breaking of C–H bonds, a mechanism that may also apply to other organic molecules.
Interestingly, other hydrocarbons failed to produce similar results, underscoring adamantane’s unique stability for diamond growth.
Beyond its immediate implications, the discovery raises new questions about natural diamond formation in meteorites and could inform quantum dot production, essential for quantum computing technologies.
The researchers emphasized that the findings challenge conventional assumptions about electron behavior. Instead of damaging organic molecules, electrons in this process facilitate precise chemical reactions — paving the way for innovative approaches to diamond synthesis and molecular engineering.
