When Professor Emiliano Cortés peers through his microscope at a single nanoparticle—smaller than one-thousandth the width of a human hair—he sees something no scientist could see clearly before. He sees a tiny universe of difference.
Nanocrystals are already in your television, your laptop, and the screen you're reading this on. These specks of material, smaller than viruses, help power the displays we use every day. Scientists believe they could also unlock better solar panels, more sensitive medical sensors, and new quantum computers. But here's the problem: when manufacturers make billions of these particles at once, they don't all come out the same. And until now, there was no good way to check quality particle by particle.
"For their function in devices, these average values are insufficient," says Cortés, who works at LMU Munich's Nano-Institute. "Each individual nanoparticle can behave differently—for example, in its size or in how efficiently it emits light."
Now, Cortés and his team have published a breakthrough in the journal Nature Materials. They've created a light-based method that can examine thousands of individual perovskite nanocubes directly while they float in liquid. The nanocubes they studied are smaller than 20 nanometers (that's about 0.0008 inches). Using a technique called iSCAT microscopy, the researchers measured each particle's size and how well it glowed, doing it fast enough to test thousands in a short time.
One surprising finding: smaller nanocrystals actually glow more efficiently than larger ones. "This understanding is crucial for fully exploiting the potential of perovskites for high-performance and scalable optoelectronic devices," says Professor Alexander Urban, whose group at LMU created the nanocrystals used in the study.
The research wasn't easy. Perovskite nanocrystals are sensitive—they can change when exposed to strong light, oxygen, or moisture. "We had to ensure that we were really measuring the original material rather than a degradation product," Cortés explains. Building the data analysis system to handle thousands of measurements was another challenge, says Dr. Andrea Mancini, a co-first author of the study.
The method's potential has already attracted serious investment. A grant of 2.45 million euros is supporting further development of the patented technology through a project called iNSyT One, led by Dr. Christoph Gruber, the study's first author. The goal: turn this lab technique into a product that factories could use to check nanocrystal quality quickly and precisely.
For the millions of devices already powered by nanocrystals—and the ones not yet invented—this new window into the microscopic world could make them work better, last longer, and cost less to produce.