Foldable phones, explained

With reports that Samsung Electronics Co. is readying to launch a foldable-screen smartphone, UB engineer Shenqiang Ren says the key technology behind such a product is the advancement of organic semiconductors.

“Smartphones, tablets and other electronic devices don’t bend because they are made of inorganic crystalline semiconductors and other materials that are rigid. As a result, they break under stress,” says Ren, professor in the Department of Mechanical and Aerospace Engineering in the School of Engineering and Applied Sciences.

“The key to developing foldable phones and other stretchable electronics has been the progression of organic semiconductors. These are specially arranged materials, often consisting of carbon or hydrogen, which are strong, yet exceptionally pliable. The organic light-emitting-diode screen often mentioned with the Samsung effort is an example of this,” says Ren, also a member of UB’s RENEW Institute.

“Recently, researchers have made tremendous advancements in organic semiconductors. These include materials that assemble themselves, stretch to greater lengths and are more adaptable to electronics,” he says.

For example, Ren published studies showing how an organic semiconducting polymer can be stretched up to 2,000 percent of its original shape, and be used to transduce and store energy. The effort was inspired by kirigami, a variation of origami that involves folding and cutting pieces of paper.

Ren’s work has been funded by the National Science Foundation, the U.S. Army Research Office, the U.S. Department of Energy and other sources.