Key Takeaways
- Researchers from Drexel University and Seoul National University have developed a flexible and stretchable organic light-emitting diode (OLED) that can be used in wearable technology and mobile displays.
- The new OLED technology improves on existing technology by integrating a flexible, phosphorescent polymer layer and transparent electrodes made from MXene nanomaterial.
- The OLED can be stretched to 1.6 times its original size while maintaining most of its luminescence.
- The technology has the potential to enable real-time health monitoring and wearable communications technology.
- The research was supported by the U.S. National Science Foundation and the National Resource Foundation of Korea.
Introduction to Flexible OLEDs
The development of flexible and stretchable organic light-emitting diodes (OLEDs) has the potential to revolutionize the field of mobile technology and wearable devices. Researchers from Drexel University and Seoul National University have made a significant breakthrough in this area by creating an OLED that can be stretched to 1.6 times its original size while maintaining most of its luminescence. This technology has the potential to enable the creation of on-skin sensors that can show changes in temperature, blood flow, and pressure in real-time.
The Challenges of Flexibility
One of the major challenges in developing flexible OLEDs is the durability of their luminescence after repeated mechanical flexion. The current technology used in flexible OLEDs has limitations due to the transparent conductor layer, which limits their stretchability. The researchers addressed this issue by integrating a flexible, phosphorescent polymer layer and transparent electrodes made from MXene nanomaterial. The result is an OLED that can be stretched to 1.6 times its original size while maintaining most of its luminescence.
A Material Solution
The researchers used a special type of organic layer that chemically coaxes more charge unions, exciton creation, and light production. The material, which they call an exciplex-assisted phosphorescent (ExciPh) layer, is intrinsically stretchable and its chemical composition can alter the energy level of the charges to enable more of them to form excitons and produce light. The ExciPh material allows more than 57% of excitons to be used to produce light, which is significantly higher than the current emissive materials used in OLEDs.
The Role of MXene
The researchers also developed high-quality, highly conductive, transparent, stretchable electrodes that improve the disbursal of charges into the ExciPh layer. The electrodes were made by combining MXene, a type of highly conductive, two-dimensional nanomaterial, with silver nanowires. The MXene-based electrodes provide a percolation network for the charges that helps to ensure more of them reach the light-producing polymer layer before they combine to form excitons. This results in optimized charge injection and helps the OLED maintain its luminescence while it is being flexed.
Testing the Limits
The researchers tested the OLEDs by creating a set of flexible green OLED displays, one in the shape of a heart and another displaying a set of numbers. They measured the charge-to-exciton conversion rate and their performance under strain and repeated use. The results showed that the OLEDs performed better than those reported in previous research, both in light production and energy efficiency. Stretching tests also showed that the device’s performance dropped by only 10.6% at 60% of its maximum strain, and it retained 83% of its light production efficiency after 100 cycles of 2% strain.
Future Applications
The researchers believe that this technology will play an important role in real-time health care monitoring and wearable communications technology. Future research could entail testing different flexible substrate materials, tailoring organic layers for producing different colors and light intensity, and streamlining the OLED production process. The development of flexible and stretchable OLEDs has the potential to revolutionize the field of mobile technology and wearable devices, and this research is a significant step towards achieving that goal.
Conclusion
In conclusion, the development of flexible and stretchable OLEDs is a significant breakthrough in the field of mobile technology and wearable devices. The researchers from Drexel University and Seoul National University have made a major contribution to this field by creating an OLED that can be stretched to 1.6 times its original size while maintaining most of its luminescence. This technology has the potential to enable real-time health monitoring and wearable communications technology, and future research will focus on testing different flexible substrate materials, tailoring organic layers, and streamlining the OLED production process.