Researchers at Purdue University and the University of Virginia have designed peelable electronic films that can be cut and pasted onto any object, offering new sensing capabilities to everything from toy blocks to unmanned aircraft.

"We could customize a sensor, stick it onto a drone, and send the drone to dangerous areas to detect gas leaks, for example," said Chi Hwan Lee, Purdue assistant professor of biomedical engineering and mechanical engineering, in a recent press release.

Using a new fabrication technique, called “transfer printing,” Lee and his colleagues created a kind of electronic sticker that supports new Internet of Things applications, such as turning an ordinary flower pot into one that senses temperature and light changes.

“This technology enables sticker-like thin-film sensors or electronics which can be simply pasted onto a surface or substrate of interest, which would be highly valuable in the ubiquitous IoT sensing applications,” Lee told Tech Briefs. “It can endow any surface with desired sensing capability or electronic functionalities.”

The thin-film electronic circuit can peel easily from its silicon wafer with water, making the wafer reusable for building a nearly infinite number of circuits. (Image Credit: Chi Hwan Lee)

The researchers demonstrated capabilities on various objects in a paper recently published in the Proceedings of the National Academy of Sciences.

Most of today’s traditional electronic circuits are built individually atop a flat and rigid silicon wafer. The wafer substrate, however, must frequently be replaced when undergoing the high temperatures and chemical etching required to remove an IC.

Lee’s “transfer printing” method uses just a single wafer to fabricate a high quantity of thin films holding electronic circuits.

A ductile metal layer, like nickel, is inserted between the electronic film and the silicon wafer, making the separation possible in water. No high temperatures or chemicals required.

“You can potentially build any kind of thin-film sensors on conventional wafers by using traditional fabrication methods, and then this technology can physically separate the functional layer from the wafer,” said Lee.

The functional device rests on temporary reusable tape. The thin-film electronics can then be trimmed and pasted onto any surface, providing electronic features to a variety of objects, including whiteboards, building windows, and desks.

“The physical peeling of high-performance industrial-grade thin-film sensors or electronics from the fabrication native wafer is novel and valuable because the peeled thin-film device can be used anywhere and anyplace,” said Lee.

Where do you see these peelable thin-film devices being used? Share your comments and questions below.