Chemical and Biomolecular Engineering at Illinois

Researchers develop dynamic templates critical to printable electronics technology

When it comes to efficiency, sometimes it helps to look to Mother Nature for advice – even in technology as advanced as printable, flexible electronics.

Researchers at the University of Illinois have developed bio-inspired dynamic templates used to manufacture organic semiconductor materials that produce printable electronics. It uses a process similar to biomineralization – the way that bones and teeth form. This technique is also eco-friendly compared with how conventional electronics are made, which gives the researchers the chance to return the favor to nature.

from bottom right, clockwise: Ying Diao, professor of chemical and bimolecular engineering; Diwakar Shukla, professor of chemical and bimolecular engineering; Chuankai Zhao, graduate student; and Erfan Mohammadi, graduate student.
Illinois researchers have developed a new dynamic template that could be critical to the advancement of printable electronics technology. From bottom right, clockwise: Ying Diao, professor of chemical and biomolecular engineering; Diwakar Shukla, professor of chemical and biomolecular engineering; Chuankai Zhao, graduate student; and Erfan Mohammadi, graduate student.

Templating is used for making near-perfect semiconductors to enhance their electronic properties, or to modulate the spacing between atoms for better electronic properties. These templates help to properly align the atoms of semiconductor materials, typically silicon or germanium, into the form that is needed.

However, this conventional methodology only works well for rigid nanoelectronic devices. The larger, more disordered organic polymer molecules needed to make flexible electronics cannot arrange around a fixed template.

In a new report in the journal Nature Communications, chemical and biomolecular engineering professor Ying Diao, graduate student Erfan Mohammadi and co-authors describe how the biomineralization-like technique works.

In nature, some biological organisms build mineralized structures by harvesting or recruiting inorganic ions using flexible biologic polymers. Similarly, the templates Diao’s group developed are made up of ions that reconfigure themselves around the atomic structure of the semiconductor polymers. This way, the large polymer molecules can form highly ordered, templated structure, Diao said.

This highly ordered structure overcomes the quality control issues that have plagued organic semiconductors, slowing development of flexible devices.

“Our templates allow us to control the assembly of these polymers by encouraging them to arrange on a molecular level. Unlike printing of newspapers, where the ordering of the ink molecules does not matter, it is critical in electronics,” Diao said.

The manufacturing process that can use these dynamic templates is also eco-friendly. Unlike conventional semiconductor manufacturing methods, which require temperatures of about 3,000 degrees Fahrenheit and produce a significant amount of organic waste, this process produces little waste and can be done at room temperature, cutting energy costs, Diao said.

“Our research looks to nature for solutions,” Diao said. “In nature, polymers are used to template ions, and we did the opposite – we use ions to template polymers to produce flexible, lightweight, biointegrated electronics at low cost and large scale.”

Other co-authors of this work include graduate student Ge Qu and postdoctoral scholar Fengjiao Zhang of chemical and biomolecular engineering; professor Jian-Min Zuo and graduate student Yifei Meng of materials science and engineering; and professor Jianguo Mei and graduate student Xikang Zhao of Purdue University.

The U. of I., the National Science Foundation, the United States Department of Energy and the Office of Naval Research Young Investigator Program supported this research.

By Lois Yoksoulian, Physical Sciences Editor, University of Illinois News Bureau; 217-244-2788; leyok@illinois.edu

To reach Ying Diao, call 217-300-3505; yingdiao@illinois.edu.

The paper “Dynamic-template-directed multiscale assembly for large-area coating of highly-aligned conjugated polymer thin films” is available from the U. of I. News Bureau.