Printable electronics are seen as the wave of the future for electronic devices, as form factors go smaller, more flexible, and even flatter.
Researchers at Duke University have made a breakthrough in this endeavor with the invention of what they said is the first simple technique for printing electronics in place, paving the way for applications such as electronic tattoos and bandages.
|Two electronically active leads directly printed along the underside of Duke graduate student Nick Williams’s pinky successfully light up an LED when a voltage is applied. The process is part of a method developed by researchers there to fabricate print-in-place electronics. (Image source: Duke University)|
A team led by Aaron Franklin, the a professor of electrical and computer engineering at Duke, developed the fully print-in-place method, which researchers said is gentle enough to work on delicate surfaces including paper and human skin.
“Most means of making electrics require many, many processing steps,” Nick Williams, a Duke PhD student of electrical and computer engineering, explained to Design News. “Even with simple, low-cost electronics fabrication process, like printed electronics, there are many further steps after deposition that are required to achieve the desired properties.”
The process the team designed, however, is far simpler, and more of a “step towards the fully printed ideal that everyone expects when we think of printed electronics,” he told Design News.
“We have developed the first recorded transistor that has been completely fabricated in a printer,” Williams told us. “The only procedure we did was a quick rinse. All of this could be automated to take humans completely out of the process, and a long-term the goal would be for a black-box fabrication of electronics where you insert your desired substrate and you can remove a fully functioning circuit.”
Solving Previous Challenges
Researchers developed a number of inks to get the desired material properties for their method and result, Williams said. They also aimed to solve a historical challenge with developing printed electronics, which is that they are unstable in air, decreasing their utility, he said.
To do this, the team ultimate used two-dimensional materials to achieve the desired materials properties at room temperature, developing a hexagonal boron nitride ink that allowed the team to print a stable dielectric material at low temperature, Williams told Design News.
“The 2D structure of hexagonal boron nitride allows for this material to be insulating immediately after printing without any further post-processing,” he explained to us.
The team also developed a silver nanowire ink that is immediately conductive after printing, which allowed the team to print at room temperature and achieve the same levels of conductivity, Williams said.
“Almost all other inks require sintering at temperatures above 150 °C,” he told us. Researchers published papers online about their work both in the journal Nanoscale and in the journal ACS Nano.
Uses and Future Design
Researchers envision that their work can pave the way for printers that can develop print-in-place electronics and might become as ubiquitous as 3D printers are becoming today, Williams said.
“Children are raised now knowing that they can print almost any shape they want,” he told Design News. “We would like to expand that to include the intimate incorporation of electronics.”
The research also paves the way for new designs for medical applications, including customizable printed electronic tattoos used for healthcare purposes, Williams said.
“These could be used for short term, non-invasive monitoring of patient vitals and well-being,” he told Design News, adding that, “really, the possibilities [for applications] are endless.”
Researchers plan to continue to develop the technology and make improvements to its performance to “reduce the processing steps to make these devices as easy to fabricate as possible,” Williams told us. The team also aims to expand the scope of applications for their work, he said.
Elizabeth Montalbano is a freelance writer who has written about technology and culture for more than 20 years. She has lived and worked as a professional journalist in Phoenix, San Francisco and New York City. In her free time she enjoys surfing, traveling, music, yoga and cooking. She currently resides in a village on the southwest coast of Portugal.