UCSB researchers teamed up with North Carolina State physicists to determine why certain materials are better than others for use in printable electronics.
Through the use of powerful X-rays that can be used to see down to the molecular level of organic materials, the researchers’ findings could lead to cheaper, more efficient printable electronic devices.
UCSB materials professor Michael Chabinyc and chemistry graduate student Justin Cochran set out with North Carolina State physicists Harald Ade and Brian Collins to find out which materials worked better for these processes, in what is still a largely trial-and-error process for manufacturers of printable electronics.
Printed electronics work best for devices such as flat-screen displays, solar panels and luminescent clothing. The process is more efficient than conventional production techniques for the same products and could help make these devices more accessible to consumers.
While most electronics almost exclusively use silicon in their circuitry, printable electronics use fairly common printing methods to deposit inks containing organic conductive molecules onto surfaces — often polymers. In doing so, it creates circuitry for a variety of electronic devices.
Until recently, the process of selecting these organic materials and improving their performance was something of a mystery. Some materials and treatments worked better than others, and the researchers set out to discover why.
The researchers used a technique that utilized powerful X-rays to view these organic materials at the molecular level, finding a polymer’s performance as a semiconductor was heavily reliant on its molecular alignment and that this alignment was controlled by simple methods, such as heating.
Chabinyc said that polymers used in semiconductors differ in arrangement and appearance from normal polymers.
“A normal polymer — such as those used in polyethylene, or plastic bags — at the molecular level looks like a squiggly line, while the polymers used as semiconductors look more like straight rods,” Chabinyc said. “The polymers will also be arranged differently; a polyethylene bag’s molecules will be pointing all directions, while a semiconductor’s polymers will be all aligned the same way.”
With the dozens of polymers in existence and the complexity of their designs, finding a polymer that works well by chance is rare. This breakthrough is all the more important for that reason; if the researchers can isolate a handful of highly efficient materials, printable electronic items such as solar panels can be made more efficient and can be manufactured more easily.