Researchers developed a method for printing electronic circuits on irregular surfaces with pulses of light.
Printed electronics is a promising technology that can be employed to make sensors and communication devices that can be attached to a mechanical surface. These applications range from household appliances that can communicate with each other to medical diagnostic sensors that can be placed on the body to forgo invasive procedures. But attaching to surfaces poses a challenge, as printed electronics made for flat surfaces cannot be attached to rough surfaces on human skin or other such surfaces.
Researchers from the Pennsylvania State University have developed a low-cost, low-heat transfer technique that can print biodegradable electronics on a variety of complex geometries and, potentially, human skin. Their findings were reported in the journal Materials Today.
“We are trying to enable direct fabrication of circuits on freeform, 3D geometries,” said Huanyu “Larry” Cheng, Dorothy Quiggle Career Development Professor in Penn State’s Department of Engineering Science and Mechanics (ESM). “Printing on complicated objects can allow a future Internet of Things where circuits can connect various objects around us, whether they be smart home sensors, robots performing complex tasks together, or devices placed on the human body.”
For printing, the researchers covered a thin film with an ink made from zinc nanoparticles, and was attached to a stencil-like overlay on the target surface. They then pulsed high-energy xenon light through the film and within milliseconds, energy from this light excited the particles enough to transfer them to the new surface through the stencil. That new surface could be complex in shape. According to the researchers, printed objects in the experiment included a glass beaker and a seashell. The transferred zinc formed a conductive electronic circuit that could be adapted for use as a sensor or antenna.
The printing method demonstrated here is much faster and cost-efficient. According to Cheng, it can also be more sustainable.
“Our electronics upgrade every two years or so, and this creates a huge amount of electronic waste,” Cheng said. “When we look at the future, if our electronics are green enough to be flushed down the toilet, their use will be much better for the environment.”