Quantum dots refer to a semiconductor material with size of several nanometers (nm). It is an inorganic light-emitting material that can emit light by itself when electrically charged, and has excellent color reproducibility. To fully utilize quantum dots in the field of displays, however, there are several technical challenges to tackle, and these require us to develop a technology that can realize quantum dot patterns elaborately and accurately without damaging the QD performance. Professor Yeon Sik Jung and other researchers have resolved this issue by proposing a new quantum dot printing technology. By utilizing the self-assembly phenomenon of quantum dots, the team separated dots into finer patterns and successfully realized high-resolution images with ultra-low pressure printing technology. “Since the QLED quantum dot pattern is extremely thin and very sensitive to external pressure, we used ultra-low pressure transfer printing technology to prevent damage to the pattern,” explained Prof. Jung.

Maximizing performance of quantum dot light emitting elements using solvent-based ultra low pressure printing technology

The team has successfully raised the resolution of the fullcolor (red, green, blue) quantum dots array to 14,000 ppi (pixels per inch). This can be applied to next-generation quantum dot LED (Light Emitting Diode) display technology. This ultra-high resolution quantum dot printing technology developed by KAIST researchers is a breakthrough that can realize more than 100 times higher resolution than that of state-of-the-art 8K displays. The ultra-low pressure transfer printing technology using a solvent is the very first attempt made in the world, and takes an entirely different approach compared to the existing quantum dot pixel pattern implementation. This is a technologically-meaningful approach in that it has maximized the resolution of the pattern, the printing yield, and the performance of the quantum dot light emitting elements.


Further studies will follow for application of ultrafine quantum dot patterning technology to biosensors

Quantum dots are one of the most actively studied fields around the world, and will be used in different applications such as solar cells, image sensors, anti-counterfeiting technology, and cancer diagnosis. Therefore, quantum dot patterns generating an extremely-high level of resolution can be used in a wide range of applications, including highly sensitive sensors or optical elements, in addition to the field of next-generation displays. Indeed, Prof. Jung’s team is now conducting a follow-up study collaborating with a bio sector research team to apply quantum dot patterning technology to biosensors. The team plans to pattern quantum dots with high resolution for swift diagnosis of pathogen infection and apply them to new biosensing elements with high sensitivity and accuracy by using light emission as a signal.

This research was published in Nature Communications on March 11, 2020, under the title “Thermodynamic-driven polychromatic quantum dot patterning for light-emitting diodes beyond eye-limiting resolution.”

Prof. Yeon Sik Jung
2020 KI Annual Report