A research team led by Yang Ji-woong, a professor in the Department of Energy Science and Engineering at the Korea Advanced Institute of Science and Technology (KAIST), together with Professor Choi Wen-ki from the Department of New Materials at the Ulsan Institute of Science and Technology and Dr. Hyun Tae-hwan from the Nanoparticle Research Center of the Korea Institute of Basic Sciences, has developed an innovative double-layer dry transfer technology. This technology enables the precise transfer of both the light-emitting layer and the electron transport layer to the substrate, bringing a breakthrough in the field of augmented reality (AR) and virtual reality (VR), which is expected to greatly enhance the immersive experience for users.
With the rapid development of wearables, mobile devices, and Internet of Things (IoT) technologies, there is a growing demand for AR, VR, and wearable displays. The displays on these devices need to display a wealth of information in a limited space and must have ultra-high-definition picture quality to avoid discomfort for users wearing them for long periods of time.
Quantum dot nanoparticles are considered ideal light-emitting materials for next-generation displays due to their excellent color purity and color reproduction capabilities. However, the traditional dry transfer technology, although it can achieve fine pixel patterns, has not been widely used in the production of displays due to the luminous efficiency of less than 5%.
Figure: There is a breakthrough in the field of AR/VR
To solve this problem, Prof. Yeung's research team, in collaboration with Prof. Choi Man-ki and Dr. Hyun Tae-hwan, has developed a novel dry transfer technology. This technology is able to achieve high brightness at low currents, thus breaking through the limitations of conventional technologies. By reducing the interface resistance, the new high-density bilayer film exhibits an external quantum efficiency (EQE) of up to 23.3%, which is comparable to the theoretical maximum efficiency of quantum dot light-emitting devices.
Using this new technology, the researchers successfully created ultra-high-definition quantum dot patterns of up to 25,526 pixels per inch (PPI) and printed them repeatedly in an area of 8 cm × 8 cm, proving its potential in commercial production.
"With our double-layer dry transfer technology, we have significantly reduced the interface resistance and facilitated the injection of electrons, resulting in an ultra-high-definition and highly efficient light-emitting device," said Prof. Yang Zhixiong. This achievement is 23.3% on the EQE, which is close to the maximum theoretical efficiency of quantum dot light-emitting devices, which is a very exciting breakthrough.”
"We are very excited about the ability of this technology to enable higher resolution screens in VR and AR. In the future, we will continue to research quantum dots with high color reproduction and good color purity to be more widely applied to smart wearable devices.”
The research was supported by the National Research Foundation of Korea and Samsung's Future Technology Development Program, and was published in the leading international optics journal Nature Photonics in August.
