Scientists at Rice University, the University of Tennessee, Knoxville (UT Knoxville) and Oak Ridge National Laboratory (ORNL) have demonstrated the use of a very small visible beam to burn graphene into microscopic patterns.
The labs of Rice chemist James Tour, which discovered the original method to turn a common polymer into graphene in 2014, and Tennessee/ORNL materials scientist Philip Rack revealed they can now watch the conductive material form as it makes small traces of LIG in a scanning electron microscope (SEM).
The altered process creates LIG with features more than 60% smaller than the macro version and almost 10 times smaller than typically achieved with the former infrared laser.
Lower-powered lasers also make the process less expensive, Tour said. That could lead to wider commercial production of flexible electronics and sensors. “A key for electronics applications is to make smaller structures so that one could have a higher density, or more devices per unit area,” Tour said. “This method allows us to make structures that are 10 times denser than we formerly made.”
To prove the concept, the lab made flexible humidity sensors that are invisible to the naked eye and directly fabricated on polyimide, a commercial polymer. The devices were able to sense human breath with a response time of 250 milliseconds.
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