About the field of System Nano/Materials Chemistry that you are researching 

  Functional Inorganic Materials Chemistry Lab conducts research utilizing various materials based on metal-organic frameworks (MOFs) and nanoclusters. MOFs are materials where metals and organic ligands are connected in a repeating structure, which can range from one-dimensional to three-dimensional forms, offering a wide spectrum of structural possibilities. To make it easier to understand, you can think of it like building with LEGO blocks. Just as you can create various structures with LEGO blocks of different shapes and colors, MOFs can also be synthesized into different structures depending on the metals and ligands used, resulting in unique properties for each MOF. In our lab, we develop new MOFs, analyze their physical properties such as electrical conductivity, magnetism, and luminescence, and apply them to research in areas like electrochemical catalysts and battery materials. Recently, we published papers on high-conductivity MOFs with processability, MOF synthesis using ultrasound, and the use of MOFs as catalysts for water oxidation reactions.

About how you became involved in the field of Nano/Materials Chemistry

  I went through a lot of exploration and tried various fields to find what I truly wanted to pursue. I was attracted to this field because MOFs, with their repeating structures, allow us to determine the exact position of each atom and the precise structure of the material through X-ray diffraction. This clear visualization of structures was incredibly appealing to me. In research, there are often ambiguous aspects that can be challenging, but the ability to see the structure clearly was fascinating. As I continued my research, I found great enjoyment in designing molecular structures to achieve specific properties and then confirming that the synthesized material exhibited the desired characteristics. The most attractive aspect of this field now is its limitless potential for expansion. Analyzing the properties of MOFs requires various new analytical methods, and these properties can be applied in diverse fields. I believe that this is what makes the research exciting and allows our lab members to develop their experiments with interest.

About your recent research on the synthesis of metal-organic frameworks (MOFs) published in the international journal JACS

  Two-dimensional electrically conductive MOFs, with their unique porous structure and high electrical conductivity, are receiving significant attention as materials for energy storage, electrocatalysis, and even electronic devices. However, to be applied to electronic devices, the material must be processed into large-area thin films, but conventional solvothermal synthesis typically results in poorly processable powder forms of MOFs. These powders are challenging to process into thin films because the strong interlayer interactions in their 2D structures prevent easy separation. Our recent publication in JACS introduced the first MOF that enhances both conductivity and processability through solution-phase processing by modifying the molecular structure of the ligand. Specifically, we synthesized a new 2D electrically conductive MOF by introducing an amine group, which has Brønsted-Lowry acid-base activity, into the ligand. By reacting this amine group with organic acids, we created a charged structure that weakened the interlayer interactions, allowing the MOF to dissolve uniformly in solution. Additionally, the strong π-electron donor properties of the amine group enhanced electron delocalization in the metal-ligand nodes, significantly increasing electrical conductivity. Furthermore, by adding or removing the acid, we were able to adjust the conductivity by up to five times. This opens up new possibilities for creating MOF-based devices, providing a novel method for easily controlling the electrical properties when applied to electronic devices.

About your current research and the ultimate goals you hope to achieve

  Our lab is engaged in various applied research based on MOFs. We are exploring the use of MOFs as materials for energy storage devices like batteries, and we are also working on synthesizing new MOFs by designing different ligands, as demonstrated in our recent publication. Additionally, we are investigating the relationship between structure and luminescence properties in various structures created using clusters, developing new synthesis methods for alloy clusters, and more. We are also interested in incorporating AI technology into our research. Ultimately, our goal is to study the correlation between the physical properties of materials and their molecular structures and to synthesize materials with targeted properties that can be applied in energy storage, electrochemical catalysis, and next-generation devices in various industries.

You earned your Ph.D. from MIT. Could you offer some advice to POSTECH students who are interested in studying abroad?

  When I first decided to study abroad, I thought everything would be great as long as I went to a good school. I had completed my master’s degree and felt somewhat confident in my research. However, when I actually arrived, I found the workload and assignments overwhelming, with many exams to take and teaching assistant duties. The atmosphere was more competitive than in Korea, and it was quite challenging during the early years, as I had to compete with classmates who had already done much more extensive studies in their undergraduate programs. The pressure was significant since grades were given on a curve, and lab selection was also highly competitive. It was incredibly challenging to excel in a different language and culture. I felt like I had to put in several times more effort than I did in Korea. There were many difficult and discouraging moments, but there were also many rewarding ones. I learned a lot. I think it’s important to approach this challenge with a mindset of giving it your all. I often get asked whether studying abroad is a good choice or what preparations are needed, but it really depends on the student’s personality and situation. If you are considering studying abroad and have any concerns, please feel free to schedule a meeting with me!