<(from left) Professor Seunghyup Yoo, Dr. Donggyun Lee, Professor Hanul Moon of Dong-A univ.>
A research team led by Professor Seunghyup Yoo from our School has successfully developed a stretchable organic light-emitting diode (OLED) display in collaboration with Professor Hanul Moon (KAIST EE alumus) from Dong-A University and ‘Hyper-realistic Device Research Division’ of the Electronics and Telecommunications Research Institute (ETRI). The developed stretchable display boasts one of the highest luminous area ratio and, moreover, maintains resolution quite well even when stretched.
The joint research team developed an ultrathin OLED with exceptional flexibility and embedded part of its luminous area between two adjacent isolated rigid “islands”. This concealed luminous area gradually reveals itself when stretched, compensating for any reduction in the luminous area ratio. Conventional stretchable displays typically secure performance by using fixed, rigid luminous parts, while achieving stretchability through serpentine interconnectors. However, space dedicated to these non-luminous serpentine interconnectors reduce the overall luminous area ratio, which decreases even further when the display is stretched as the interconnectors expand.
The proposed structure achieved an unprecedented luminous area ratio close to 100% before stretching and only exhibited a 10% reduction after 30% stretching. This is in stark contrast to existing platforms, which experience a 60% reduction in luminous area ratio under similar conditions. Additionally, the new platform demonstrated mechanical stability, operating reliably under repeated stretch-and-release cycles.
The research team illustrated the applicability of this technology to wearable and free-form light sources that can operate stably on curved surfaces such as spherical objects, cylinders, and human body parts, accommodating expansions like balloon inflation and joint movements and demonstrated the potential for stretchable displays that can compensate for resolution loss during stretching by independently driving the hidden luminous areas.
The study, with Dr. Donggyun Lee (currently a research fellow at Seoul National University) as the first author, was published in the June 5, 2024 issue of Nature Communications (Title: Stretchable OLEDs based on a hidden active area for high fill factor and resolution compensation, DOI: 10.1038/s41467-024-48396-w) and was also featured in an online news article by IEEE Spectrum as well as several domestic newspapers.
This research was supported by the Engineering Research Center Program (Attachable Phototherapeutics Center for e-Healthcare) backed by the National Research Foundation of Korea and the Research Support Program of ETRI (Developing Independent and Challenging Technologies in ICT Materials, Parts, and Equipment.).
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