[Image above] Flexible circuit board. Credit: Grant Hutchinson; Flickr CC BY-NC-ND 2.0
When it comes to the future of consumer electronic devices, efficiency, durability, and flexibility are paramount.
Long battery life, shatter-resistant bodies, and foldable displays are generating buzz this year—especially for smartphones, when you consider that nearly 50% of smartphone users in the U.S. have either damaged or lost their device at some point during ownership, according to a study conducted by Verizon and KRC Research.
Speaking of durability, Corning recently unveiled the next generation of tough with Gorilla Glass 5, which “touts dramatically improved drop performance compared with competitive glass designs and earlier versions of Gorilla Glass,” according to Corning’s website. To date, Gorilla Glass is incorporated into devices manufactured from more than 40 major brands and over 1,800 product models, totaling 4.5 billion devices since its launch in 2007.
And flexibility is part of durability—resistance to fracture under strain. So researchers are turning to conductive advanced materials that have potential for use in flexible electronics. In fact, earlier this week we reported that researchers from the Korea Advanced Institute of Science and Technology are developing wearable displays that are “thin as skin” using novel transparent oxide thin-film transistors.
Many existing electronic devices use rigid, inorganic materials. So researchers at the Pohang University of Science and Technology (POSTECH) in Korea are looking for ways to make electronic devices out of soft, organic materials instead.
For next-generation, flexible, durable electronic applications, conducting polymers are a promising organic material candidate due to their malleability, lightweight structure, and conductivity, according to a POSTECH press release. The challenge, however, is that their charge carrier mobility is much lower than inorganic materials.
“Many researchers have attempted to enhance the charge carrier mobility by increasing polymers’ crystallinity, which is the degree of structural order. However, this approach is inherently restrictive in terms of mechanical properties. In other words, an increase in the crystallinity results in a decrease of the mechanical resilience, at least according to the conventional norm,” the release explains.
Taiho Park and Chan Eon Park—researchers at the Department of Chemical Engineering at POSTECH—and their students Sung Yun Son and Yebyeol Kim have found a simple-yet-unconventional workaround to this limitation. The team developed a low crystalline conducting polymer that shows high-field effect mobility.
To do this, the researchers “introduced monomers without side chains into the polymer and utilized unconventional localized aggregates as stepping stones to expedite charge transport in the microstructure of the polymer,” the release explains. “The resulting increase in the backbone planarity and chain connectivity of the polymer enhanced charge transport along and between the polymer chains.”
This study, according to the researchers, could pave the way for “a new strategy in molecular design that allows faster charge transport without losing any mechanical advantages” and open up new research and application possibilities for soft electronics.
The study, published in the Journal of the American Chemical Society, is “High-field-effect mobility of low-crystallinity conjugated polymers with localized aggregates” (DOI: 10.1021/jacs.6b01046).