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World’s First Synthesis of Metastable Phase Quantum Dots Using Light Energy

When the size of particles are reduced to several nanometers (nm), the electrical and optical properties of the particles are significantly changed. In physics, semiconductor nanoparticles are referred to as quantum dot (QDs). In last two decades, many studies have been conducted on QDs to increase the efficiency of products and devices which adopt nanoscale materials into them.
In the past, metastable phase QDs, having a special QD phase, were synthesized at a temperature above the boiling point of a compound solvent for inducing the QD. However, the thermal energy-based method has temporal limitations because several minutes to hours of time are required to complete the synthesis. To overcome the limitations, the research group of Professor Emeritus Duk Young Jeon in Department of Materials Science and Engineering has successfully synthesized the world’s first metastable phase QD by utilizing light energy.

|Awakening Future of Industry Through Display Innovation|

From heat to light: Shift of QD synthesis energy
“We used a Xenon flash lamp that flashes 60 or more times per second to synthesize QDs within a second. However, the PLQY (photoluminescence quantum yield) was not so good. The PLQYs of the conventional heat energy-based method are over 90%, but that of our method has produced 42% so far. The significance of our work is that light energy (a light source) is employed to synthesize QDs for the first time in the world.
Professor Jeon said that he focused on ‘how to reduced the QD synthesis time’ and also ‘how to increase the performance of the synthesized QD materials.’ The first goal was fulfilled by reducing the synthesis time from several minutes or hours to about one second by changing the energy source of the synthesis (from heat to light). As the low PLQY value (42%) shows, further improvement is needed to fulfill the second goal. However, Professor Jeon emphasizes that the present accomplishment is still signifiant.
“More time is necessary. We have gone through unexpected obstacles until now. I’m sure that some younger researchers will find the solutions. Our team in the Department of Materials Science and Engineering was able to obtain the meaningful results through systematic cooperation with various other groups in the fields of synthetic process design innovation, transmission electron microscopy, and simulation.”

Future-oriented technology with high impact on industry
The results of this work can be summarized as follows ‘Essential display materials having excellent properties that may not be obtained by a chemical reaction under an equilibrium state were discovered through the light-matter interactions that are extremely rapid, powerful, and precisely controlled in multiple scales.’ The novel display technology is expected to overcome the current technical limitations, enabling multi-dimensional communication and creating new value through the human-object interface. This suggests that the virtual reality (VR) or augmented reality (AR) can evolve into a form in which humans can play certain roles. “In the future, transparent display materials may be developed in a form that may bind to human body.” Professor Jeon anticipated that the new technological trend will lead the electronic and cultural industry of Korea. He added, “Moreover, I’m looking forward to seeing our technology can provide a momentum to all kinds of industry in Korea by means of the synergic effects in semiconductor, healthcare and biotechnology.“

Prof.Duk Young Jeon
2021 Annual Report

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