Teams from Drexel University (USA) and Seoul National University have created a prototype of an OLED display that can stretch and double in size without losing brightness. The development involved scientists from the group of Ukrainian-born professor Yuriy Gogotsi, a co-discoverer of display materials.
Teams from Drexel University (USA) and Seoul National University have created a prototype of an OLED display that can stretch and double in size without losing brightness. The development involved scientists from the group of Ukrainian-born professor Yuriy Gogotsi, a co-discoverer of display materials.
The key change in the design was the transparent electrode: instead of the traditional indium tin oxide (ITO), which works well in flat screens but cracks under load, the team used MXene-class materials. As TechSpot writes, MXene is an ultra-thin conductive «layer» that combines high electrical conductivity with mechanical flexibility: under tension, they can deform due to bending and mutual sliding between the layers, without losing contact as quickly as brittle oxide films. The authors call the use of MXene as a transparent electrode one of the key factors that allowed combining high brightness and stretchability in the prototype of the new OLED.
The prototype used a very thin MXene film (on the order of tens of nanometers), which allowed it to maintain conductivity even when the display is stretched. This is important for «living» scenarios, namely screens in wearable gadgets, smart clothing, soft robotics and medical sensors that work on the surface of the body and constantly deform under movement.
In addition to replacing the electrode, the researchers also redesigned the organic «filling» of the OLED. They added two additional layers that optimize the movement of charges inside the structure: one more effectively directs positive charges to the light-emitting zone, the other helps to «return» some of the energy that is usually lost as heat. As a result, the prototype showed an external quantum efficiency of 17% — an indicator of how efficiently electrical energy is converted into visible light. The material notes that this is one of the highest results for intrinsically stretchable OLEDs, and the theoretical limit for this class of technologies is estimated at about 20%.
The authors also point out the barrier that still separates development from mass production: OLEDs are sensitive to oxygen and moisture, and reliable protective coatings are usually rigid and do not tolerate stretching. Therefore, the next step is to create a durable flexible seal and test how the display maintains uniformity of luminescence after multiple deformation cycles.
Previously, dev.ua wrote about how a court in the US found that some Samsung devices infringed two patents of Pictiva Displays on OLED display technology, and ordered them to pay $191.4 million. The manufacturer disagrees with the decision and said it would appeal.
