Clothes as Displays? ... Development of Wearable OLED Fibers

KAIST Professor Choi Kyung-chul's Team: "Fashion, Functional Clothing, Safety, Vehicle Design and More Applications Possible"

[Asia Economy Reporter Kim Bong-su] Soon, clothes that can freely change colors, patterns, images, or play videos are expected to appear.

The Korea Advanced Institute of Science and Technology (KAIST) announced on the 12th that Professor Choi Kyung-chul's research team from the Department of Electrical Engineering and Computer Science has developed organic light-emitting diode (OLED) electronic fibers capable of information display.

These electronic fibers are materials in a wearable form. Unlike existing two-dimensional planar devices, they have a one-dimensional fiber structure that can withstand various human body movements and provide excellent wearability and portability, attracting attention as the next-generation form factor. In particular, light-emitting electronic fibers are gaining significant attention for their potential applications in fashion, functional clothing, medical, safety, and vehicle design.

However, electronic fibers that emit light developed so far have shown insufficient electro-optical performance for use as displays. Research has been conducted only on simple device units or two-dimensional planar units with high aspect ratios, making it difficult to develop application technologies.

To realize OLED electronic fiber displays, the research team focused on achieving high electro-optical performance and establishing an addressing system. First, they designed an RGB phosphorescent OLED device structure suitable for a cylindrical fiber structure with a diameter of 300 micrometers (?m), and using their proprietary deep coating process, developed OLED electronic fibers comparable to planar OLED devices.

In particular, by successfully implementing high-efficiency phosphorescent OLEDs on fibers, they demonstrated luminance levels up to 10,000 cd/m2 (candela per square meter) and high current efficiency of about 60 cd/A (candela per ampere). This corresponds to more than five times the current efficiency compared to existing technologies.

Additionally, based on the OLED electronic fibers, the research team designed contact areas on the fibers to build a woven addressing system for stable display operation. They confirmed functionality by displaying information such as characters, demonstrating wearability.

The research team explained that these electronic fibers possess the brightness, high current efficiency for low power consumption, low driving voltage, and addressability that are essential from the perspective of display devices.

Hwang Yong-ha, a researcher in Professor Choi’s team who led the study, said, "We focused on implementing the essential core technologies required for fiber-based display realization. We expect that electronic fibers will provide excellent wearability and portability while implementing display functionality, making them suitable for various applications such as fashion and functional clothing."

The research results were published as a front cover paper in the prestigious international journal in the nano field, Advanced Functional Materials, on the 3rd of this month.