Michigan State University scientists have discovered a method of producing crystals on demand by “drawing” them on the surface of gold particles using an ultrafast laser.
Funded by the United States Department of Defense, the novel approach could enable scientists and engineers to create customized crystals, such as those used in LEDs, solar panels, and medical imaging technologies, on demand. This is in contrast to the current methods of harvesting naturally forming crystals or growing them in the laboratory.
In modern electronics, devices like smartphones and television screens utilize crystals to generate visually stunning displays. However, according to Elad Harel, associate professor in the Department of Chemistry and senior author of the new study, these methods are not always predictable, which can cause supply line consistency and production difficulties.
“When using traditional growing methods, crystals can form at random times and locations, so the results might not always be the same,” Professor Harel explained.
Still, rapidly evolving technologies will only increase demand for customized crystals of exceptional quality, making the development of improved methods for creating standardized designs increasingly necessary. The issues are especially pressing on a type of crystal called lead halide perovskites, which are used in solar cells, medical imaging technologies, and LED screens.
Hoping to find a new approach, the researchers bypassed the typical, complicated steps involved in crystal manufacturing, including using a small “seed” crystal to spur growth. Instead, Harel and colleagues turned to the university’s high-powered lasers.
In a series of experiments, the team pointed ultrafast lasers at gold nanoparticles, which are gold particles measuring less than one thousandth the width of a human hair. When examining the results under high-powered microscopes, they found that wherever the laser light interacted with the gold, excess heat was generated. This excess heat led to the growth of crystals. The team said they were even able to witness the process in real time.
“It’s like having a front-row seat to watch the very first moments of a crystal’s life under a microscope, only here we can also steer how it develops,” said Dr. Md Shahjahan, a research associate at MSU and first author of the paper.
The team also likened the comparatively simple process of laser-grown crystals to using a laser to engrave artwork into wood or metal, noting that this ability to ‘draw’ crystals on demand provides researchers with a previously unavailable level of control “that could transform fields ranging from clean energy to quantum technologies.”
“With this method, we can essentially grow crystals at precise locations and times,” Shahjahan explained.
Following the successful experiments, Elad’s team is returning to the lab to expand their experiments while attempting to refine and improve the process. For example, they plan to try multiple lasers operating at different color wavelengths to draw even more intricate crystal patterns.
They also hope to create “entirely new materials” that cannot be manufactured with conventional methods. Ideally, they would also create crystals that can be tested in actual electronic devices to determine what improvements may be needed to commercialize the process.
“Now that we can ‘draw’ crystals with lasers, the next step is to make larger and more complex patterns, and to test how these crystals perform in real devices,” Harel said.
In the study’s conclusion, the researchers note that, in addition to opening the path to custom-drawn crystals, their findings can help expand the knowledge of how crystals form, which they describe as “a notoriously tricky area of chemistry.”
“We’re just beginning to scratch the surface of what’s possible,” Harel said. “This is opening a new chapter in how we design and study materials.”
The study “Nanoscale Plasmonic Heating Induced Spatiotemporal Crystallization of Methylammonium Lead Halide Perovskite” was published in ACS Nano.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.