A research team in South Korea has developed a textile-based wearable display that is machine washable and powered by solar energy.
Prof Kyung Cheol Choi from the School of Electrical Engineering at KAIST (Korea Advanced Institute of Science and Technology) and his team fabricated their wearable display modules on real textiles that integrated polymer solar cells (PSCs) with organic light emitting diodes (OLEDs).
According to KAIST, PSCs have been one of the most promising candidates for a next-generation power source, especially for wearable and optoelectronic applications because they can provide stable power without an external power source, while OLEDs can be driven with milliwatts. A major drawback for both has been their vulnerability to external moisture and oxygen. The encapsulation barrier is essential for their reliability. The conventional encapsulation barrier is sufficient for normal environments; however, it loses its characteristics in aqueous environments.
To tackle this issue, the team employed a washable encapsulation barrier that can protect the device without losing its characteristics after washing through atomic layer deposition (ALD) and spin coating. With this encapsulation technology, the team confirmed that textile-based wearing display modules – including PSCs, OLEDs, and the proposed encapsulation barrier – exhibited little change in characteristics after 20 washes with 10-minute cycles. Moreover, the encapsulated device operated stably with a low curvature radius of 3mm and boasted high reliability.
Finally, it exhibited no deterioration in properties over 30 days even after being subjected to bending stress and washing. Since it uses a less stressful textile, compared to conventional wearable electronic devices that use traditional plastic substrates, this technology can accelerate the commercialisation of wearable electronic devices.
Professor Choi said, “I could say that this research realised a truly washable wearable electronic module in the sense that it uses daily wearable textiles instead of the plastic used in conventional wearable electronic devices. Saving energy with PSCs, it can be self-powered, using nature-friendly solar energy, and washed. I believe that it has paved the way for a ‘true-meaning wearable display’ that can be formed on textile, beyond the attachable form of wearable technology.”
This research, in collaboration with Prof Seok Ho Cho from Chonnam National University and led by Eun Gyo Jeong, was published in Energy and Environmental Science.