Ruiming Lin remembers the first time he looked through the electron microscope and saw the tiny crystals his team had made. Billions could fit on a fingernail, yet these specks represented something that chemists had spent decades trying and failing to achieve.
Lin's team at the University of Chicago, working with scientists at Argonne National Laboratory, has done something remarkable: they created nanocrystals from a family of materials called metal nitrides for the very first time. The achievement, published July 15 in the journal Nature, opens new possibilities for everything from bendable lighting to medical implants that last longer in the body.
Metal nitrides are already everywhere. Gallium nitride, for example, powers nearly all modern LED lighting—from the bulbs in your home to the screen you're reading this on. These materials are tough, heat-resistant, and don't break down easily. That durability makes them ideal for consumer electronics, but it's also what made them so hard to shrink down.
Think of ordinary crystals forming like a square dance, where atoms swap partners easily. Metal nitrides, however, are more like tango dancers with extremely strong bonds—once they pair up, they refuse to let go. "If bonds cannot break during this process, that's a death sentence for nanocrystals," said Dmitri Talapin, a chemistry professor at UChicago who led the research. "Once you make an incorrect bond, everything goes south."
The team's solution was to rethink the whole approach. They used molten salts (yes, like the kind on your table, but melted) as part of the recipe, and found a specific combination of heat and pressure that let the metal-nitrogen bonds loosen just enough to rearrange. "This process is very unusual—it goes against every bit of common sense in the field," Talapin said.
The method worked not just for gallium nitride, but for nearly a dozen different metal nitrides, including ones used in medical implants, powerful superconductors, and chemical reactions called catalysts. Nanocrystals of these materials could someday be printed as ink, woven into fabrics, or blended into flexible devices—imagine a glow-in-the-dark jacket or a smartphone screen you can roll up.
Nanocrystals were important enough to earn the 2023 Nobel Prize in Chemistry, and this discovery expands what scientists can do with them. "This expands the boundaries of the field beyond what were previously fundamental constraints," Talapin said. Lin, who saw his creation under the microscope that first time, is optimistic about what comes next. "I think there will be many uses," he said.