Although only a few nanometers or micrometers in thickness, a thin film is an important part of modern electronics, with miniature semiconductors and optical coatings being two of its major applications. At present, a process called photonic sintering allows scientists to fuse nanoparticles into functional thin films. However, the procedure usually requires very high temperatures that can actually damage the material on which the films are built. Researchers, at the Oregon State University (OSU), have come up with a new technique that can construct such films at far lower temperatures and nearly 10 times more energy efficiency.
Recently published in the Scientific Reports journal, the research decodes the science behind the process of photonic sintering. To that end, it has outlined an incredibly innovative technique of thin film production, which does not involve high temperatures or even costs. According to the team, the technology could pave the way for high-quality electronic devices that are printed onto cheap substrates, like paper and plastic wrap. Speaking about the project, Rajiv Malhotra, a professor of mechanical engineering at OSU, said:
Photonic sintering is one way to deposit nanoparticles in a controlled way and then join them together, and it’s been of significant interest. Until now, however, we didn’t really understand the underlying physics of what was going on. It was thought, for instance, that temperature change and the degree of fusion weren’t related – but in fact that matters a lot.
Using a simple xenon lamp, the scientists have been able to fuse the nanoparticles together into a functioning 2D film. The new technique can be used over large substrates, and is twice as fast as the existing thermal methods. Since it requires much lower temperatures, the process is nearly 10 times more energy efficient than conventional methods. What is more, it can be used on cheap, and even flimsy, materials, such as plastic wrap and paper. Malhotra added:
Lower temperature is a real key. To lower costs, we want to print these nanotech products on things like paper and plastic, which would burn or melt at higher temperatures. We now know that is possible, and how to do it. We should be able to create production processes that are both fast and cheap, without a loss of quality.
The technology, according to Malhotra, could lead to the development of highly efficient electronic devices, including biomedical sensors, solar cells, radio-frequency identification (RFID) systems, gas sensors, and other flexible gadgets. The team is currently looking for ways to scale up the process for industrial manufacture of thin films.
The research was funded by a $1.5 million, four-year-long grant from the National Science Foundation.