Jason Ford

Flexible film could have wearable tech applications

News

Researchers from South Korea have taken a step toward more bendable electronic devices by manufacturing a thin film that keeps its useful electric and magnetic properties even when highly curved. 

The researchers describe the film in a paper published in the journal Applied Physics Letters.

Flexible electronics have been hard to manufacture because many materials with useful electronic properties tend to be rigid but the researchers have addressed this problem by taking pieces of materials like silicon and embedding them in flexible plastics.

A team of physicists and engineers from South Korea are said to have taken the same approach with bismuth ferrite (BiFeO3), which is one of the most promising materials whose electronic properties can be controlled by a magnetic field, and vice versa. Such materials are called multiferroics and attract interest for applications like energy efficient, instant-on computing.

The researchers synthesized nanoparticles of bismuth ferrite and mixed them into a polymer solution. The solution was dried in a series of steps at increasing temperatures to produce a thin, flexible film.

When the researchers tested the electric and magnetic properties of the film they found that their new material preserved the useful properties of bulk bismuth ferrite and improved them. The improved properties remained even as the film was curved into a cylindrical shape.

‘Bulk bismuth ferrite has crucial problems for some applications, such as a high leakage current which hinders the strong electric properties,” said YoungPak Lee, a professor at Hanyang University in Seoul. Mixing nanoparticles of bismuth ferrite into a polymer improved the current-leakage problem, he said in a statement, and also gave the film flexible, stretchable properties.

Flexible multiferrorics could enable new wearable devices such as health monitoring equipment or virtual reality attire, Lee said. The multiferroric materials could be used in high-density, energy efficient memory and switches in such devices, he said.

Before the new films make their debut in wearable tech, the researchers are working to further improve their multiferroic properties, as well as exploring even more flexible materials.