Rice University researchers adapted its laser-induced graphene technique to make high-resolution, micron-scale patterns, which could benefit on-chip microsupercapacitors, functional nanocomposites and microfluidic arrays.
A Rice University laboratory has adapted its laser-induced graphene technique to make high-resolution, micron-scale patterns of the conductive material for consumer electronics and other applications.
Laser-induced graphene (LIG), introduced in 2014 by Rice chemist James Tour, involves burning away everything that isn’t carbon from polymers or other materials, leaving the carbon atoms to reconfigure themselves into films of characteristic hexagonal graphene. The process employs a commercial laser that “writes” graphene patterns into surfaces that to date have included wood, paper and even food.
A laser-induced graphene Rice Owl is surrounded by photoresist material at left and stands alone at right after the excess photoresist is washed away with acetone. Rice University scientists are using the process to create micron-scale lines of conductive graphene that could be useful in consumer electronics. Courtesy: Tour Group/Rice University[/caption]
The Rice lab produced lines of LIG about 10 microns wide and hundreds of nanometers thick, comparable to that now achieved by more cumbersome processes that involve lasers attached to scanning electron microscopes, according to the researchers.
Achieving lines of LIG small enough for circuitry prompted the lab to optimize its process, according to graduate student Jacob Beckham, lead author of the paper.
“The breakthrough was a careful control of the process parameters,” Beckham said. “Small lines of photoresist absorb laser light depending on their geometry and thickness, so optimizing the laser power and other parameters allowed us to get good conversion at very high resolution.”
Because the positive photoresist is a liquid before being spun onto a substrate for lasing, it’s a simple matter to dope the raw material with metals or other additives to customize it for applications, Tour said. Potential applications include on-chip microsupercapacitors, functional nanocomposites and microfluidic arrays.
– Edited by Chris Vavra, web content manager, Control Engineering, CFE Media & Technology, [email protected].
