The quest to create inherently stretchable displays has begun.
Traditional displays are limited by rigid and inflexible components. It is therefore imperative to find innovative materials and device designs that can withstand significant stretching while retaining their functionality, essential for applications such as adaptable and wearable interface technologies.
Inherently stretchable quantum dot electroluminescent diodes
While most flexible displays on the market use organic light-emitting diode (OLED) technology with organic materials as light-emitting components, these often have disadvantages such as limited brightness and color purity issues. In contrast, quantum dot (QLED) displays offer excellent color reproduction, increased brightness, and superior longevity, making them an attractive choice for consumers who prioritize these criteria.
However, the challenge in developing flexible QLED displays lies in the very nature of the quantum dots (QD). As inorganic nanoparticles, they do not have inherent stretching properties. Efforts have been made to incorporate QD into elastic materials to create a stretchable and light-emitting composite material.
The research team from the Institute for Basic Science (IBS) led by Professor KIM Dae-Hyeong has overcome these limitations by integrating a third material into the composite to enhance carrier transmission to the QD. A semiconductor polymer, TFB, was used to improve both the stretchability of the device and the efficiency of hole injection.
The IBS researchers managed to achieve QLEDs with high brightness (15,170 cd/m²), the highest among stretchable LEDs, and a low threshold voltage (3.2 V). Even when significant force was applied to stretch the material, the device was not damaged. Even when stretched up to 1.5 times its size, there was no significant change in the distance between the quantum dots inside the device.
This research not only demonstrates the superior performance of QD in stretchable displays but also opens new avenues for further improving device performance. Future research will focus on optimizing carrier injection efficiency and stretchability across all layers of the device. This discovery lays a solid foundation for next-generation QLED technology, promising a future where display technologies are not just flexible but truly stretchable, enabling new forms of wearable electronics.
Article author: Cédric DEPOND