Prof. Kang Moon-sung’s Team in Chemical and Biomolecular Engineering, Publishes in 'Nature Communications'
A joint research team led by Professor Kang Moon-sung of the University’s Department of Chemical and Biomolecular Engineering, Professor Kim Bong-soo of UNIST, and Dr. Kang Chan-mo of ETRI has developed a new process technology. This technology enables the creation of precise micro-patterns in a quantum dot light-emitting layer without causing damage. The study’s first authors are Kim Hyuk-jun and Lim Chang-hyuk from the University, and Ham Hyo-bin from UNIST.
With the rapid advancement of virtual reality (AR) and augmented reality (AR) technologies, interest in microdisplay technology used at a very close distance to the eye is growing. Since the screen size of these devices is limited to a few inches or less, it is essential to implement Red, Green, and Blue (RGB) light-emitting layers at ultra-high resolutions of 3,000 PPI or higher. This is necessary to prevent the "screen-door effect," where pixel boundaries become visible to the human eye.
Quantum dots are gaining attention as next-generation display materials due to their excellent color reproduction and high luminous efficiency. However, for practical display applications, the quantum dot light-emitting layer must be precisely patterned into micro-pixels. Existing patterning methods have faced limitations in creating such intricate patterns with high precision while preserving the original performance of the quantum dots.
The joint research team developed a “photoresist (PR)-based indirect photopatterning” technology, which enables the formation of fine patterns while stably protecting the quantum dot light-emitting layer. In this method, a micro-pattern is first created using PR, a material commonly used in semiconductor manufacturing. A quantum dot thin film is then deposited on top, and finally, the PR is removed to leave the quantum dot pattern only in the desired locations.
To achieve this, the team introduced a cross-linking strategy that connects organic ligands on the surfaces of the quantum dots, allowing them to form a stable network structure. This structure protects the quantum dot thin film from damage caused by solvents during the patterning process or subsequent steps. Additionally, the cross-linking reaction is designed to occur at relatively low temperatures, ensuring the process remains stable while preserving the original characteristics of the photoresist pattern.
The research team achieved world-class pattern fidelity using this technology. Notably, the line edge roughness (LER), which indicates irregularities at the pattern edges, was measured at 43.1 nm for a pattern approximately 2 µm wide. This represents the lowest value reported to date for luminescent quantum dot patterns. Furthermore, the team successfully implemented ultra-high-resolution RGB patterns exceeding 4,000 PPI by sequentially depositing red, green, and blue quantum dots. Finally, by producing a 10 × 10 RGB quantum dot light-emitting diode (QD-LED) array, the team demonstrated that this technology is fully compatible with actual display device manufacturing processes.
This research was conducted with support from the Samsung Future Technology Development Program the ‘Nano and Materials Technology Development Program (National Strategic Technology Materials Development)’ and the ‘Individual Basic Research Project (Mid-Career Research) promoted by the Ministry of Science and ICT and the National Research Foundation of Korea, and was published in the international journal ‘Nature Communications’.
▶Title: Photoresist-guided indirect photopatterning of quantum dots via carbene-mediated ligand thermocrosslinking
▶ Link: https://www.nature.com/articles/s41467-026-70770-z
[SEO keyword]
Quantum Dot Micro-patterning, Next-Generation Microdisplays, Nature Communications
With the rapid advancement of virtual reality (AR) and augmented reality (AR) technologies, interest in microdisplay technology used at a very close distance to the eye is growing. Since the screen size of these devices is limited to a few inches or less, it is essential to implement Red, Green, and Blue (RGB) light-emitting layers at ultra-high resolutions of 3,000 PPI or higher. This is necessary to prevent the "screen-door effect," where pixel boundaries become visible to the human eye.
Quantum dots are gaining attention as next-generation display materials due to their excellent color reproduction and high luminous efficiency. However, for practical display applications, the quantum dot light-emitting layer must be precisely patterned into micro-pixels. Existing patterning methods have faced limitations in creating such intricate patterns with high precision while preserving the original performance of the quantum dots.
The joint research team developed a “photoresist (PR)-based indirect photopatterning” technology, which enables the formation of fine patterns while stably protecting the quantum dot light-emitting layer. In this method, a micro-pattern is first created using PR, a material commonly used in semiconductor manufacturing. A quantum dot thin film is then deposited on top, and finally, the PR is removed to leave the quantum dot pattern only in the desired locations.
To achieve this, the team introduced a cross-linking strategy that connects organic ligands on the surfaces of the quantum dots, allowing them to form a stable network structure. This structure protects the quantum dot thin film from damage caused by solvents during the patterning process or subsequent steps. Additionally, the cross-linking reaction is designed to occur at relatively low temperatures, ensuring the process remains stable while preserving the original characteristics of the photoresist pattern.
The research team achieved world-class pattern fidelity using this technology. Notably, the line edge roughness (LER), which indicates irregularities at the pattern edges, was measured at 43.1 nm for a pattern approximately 2 µm wide. This represents the lowest value reported to date for luminescent quantum dot patterns. Furthermore, the team successfully implemented ultra-high-resolution RGB patterns exceeding 4,000 PPI by sequentially depositing red, green, and blue quantum dots. Finally, by producing a 10 × 10 RGB quantum dot light-emitting diode (QD-LED) array, the team demonstrated that this technology is fully compatible with actual display device manufacturing processes.
This research was conducted with support from the Samsung Future Technology Development Program the ‘Nano and Materials Technology Development Program (National Strategic Technology Materials Development)’ and the ‘Individual Basic Research Project (Mid-Career Research) promoted by the Ministry of Science and ICT and the National Research Foundation of Korea, and was published in the international journal ‘Nature Communications’.
▶Title: Photoresist-guided indirect photopatterning of quantum dots via carbene-mediated ligand thermocrosslinking
▶ Link: https://www.nature.com/articles/s41467-026-70770-z
[SEO keyword]
Quantum Dot Micro-patterning, Next-Generation Microdisplays, Nature Communications