Do Hyun Kwak
Nowon-gu,11
Summary
M.S. in Materials Science and Engineering with strong expertise in thin-film process integration and defect engineering for heterostructure multilayer device structures. Experienced in full-stack process development of perovskite LEDs using ALD, PVD, APCVD, and Spin-coating. Proficient in plasma surface treatments, precursor synthesis, and composition engineering of ABX₃ perovskites to optimize stability and charge transport. Applied design of experiments (DOE) and advanced characterization techniques including XRD, XPS, SIMS, AFM, and FESEM to analyze and suppress interfacial and bulk defects. These efforts led to 2 first-author SCIE publications, including a featured cover article, and 3 co-authored papers.
Overview
2
2
years of professional experience
Work History
Multifunctional Additive Process Optimization
01.2024 - 01.2025
- Applied S, F element based doping for defect control and stability; achieved 30× lifetime, 6× efficiency gain.
- First-author cover article in Adv. Funct. Mater. (SCIE, IF 18.5), selected as cover.
- Built expertise in defect engineering and dopant-material interaction in thin films.
- Conducted reliability testing under humidity and bias stress conditions.
- Correlated dopant concentration with structural and optoelectronic performance.
O₂ Plasma-based Interface Defect Passivation
01.2023 - 01.2024
- Developed optimized O₂/Ar plasma treatment process for surface passivation and hydrophobicity improvement; enhanced charge transfer efficiency by 3× and power efficiency by 6×.
- Published as first author in Vacuum (SCIE, IF 4.5).
- Enhanced understanding of surface chemistry and process parameter control for interface engineering.
- Analyzed plasma-treated surfaces using Contact angle, XPS/UPS.
- Built reproducible recipe through tuning RF power and treatment time.
ALD-based Tandem PeLED CGL Fabrication
03.2023 - 11.2024
- Evaluated the potential of ALD-grown ZnSnO for application as a charge generation layer (CGL) in Tandem perovskite LEDs.
- Achieved >10% power efficiency increase in tandem devices.
- Gained practical skills in cross-functional collaboration and device architecture optimization.
- Investigated cross-layer degradation mechanisms and thermal effects.
FTO Electrode Pattern Precision Optimization
11.2024 - Current
- Optimized FTO electrode deposition process by redesigning masks and applying interval deposition, achieving a 28% improvement in pattern uniformity.
- Developed a customized CVD-based process recipe, enhancing scalability and reproducibility for transparent conductive layer fabrication.
- Identified and resolved edge-rounding and step-height deviation issues through cross-analysis of photomask layout and deposition parameters.
- Tuned critical process variables (gas flow, deposition time, and substrate temperature) to improve film thickness uniformity by 15% and reduce sidewall roughness.
Perovskite Compositional Modification for TFTs
12.2024 - Current
- Designed ABX3 perovskite compositions for wavelength control in UV-responsive active layers.
- Developed material design insight for optoelectronic property tuning and functional layer integration.
- Studied composition-property relationships affecting UV absorption and emission
- Analyzed optical response using UV-Vis and PL characterization tools.
Education
Master of Science - Materials Science & Engineering
Seoultech
Seoul 02-2025
Minor - Semiconductor Convergence Engineering
Seoultech
Seoul03-2023
Bachelor of Science - Materials Science And Engineering
Seoultech
Seoul 03-2023
Skills
- Multi-Layer Device Fabrication Techniques: ALD, PVD (RF-Sputtering, Thermal Evaporation), APCVD, Spin-Coating
- Thin-Film Process Optimization: Process recipe tuning based on device architecture and deposition methodology
- Material Selection & Design: Material selection and process design considering bandgap properties and fabrication compatibility
- RF-Plasma and Additive based Defect Engineering:
Engineered plasma-assisted defect passivation and incorporated multifunctional additives to enhance device stability and performance - Precursor Elemental Composition Engineering: Systematic tuning of A-, B-, and X-site ions in ABX₃ perovskites to control bandgap, phase stability, and optoelectronic properties through tailored precursor synthesis
- Characterization Techniques:
Morphological / Surface Analysis: FE-SEM, AFM
Crystallographic Analysis: XRD
Optical Properties Analysis: UV-Vis, PL
Chemical Composition & Bonding: XPS, FTIR, NMR
Electrical / Device Characterization: EQE, IVL, EL
Publications
1. Do-Hyun Kwak, Seung-Beom Cho, Chang-Xu Li, Yu-Na Choi, and Il-Kyu Park*, “Multifunctional FA-Triflate Treatment for Efficiency and Reliability Enhancements of Quasi-2D Perovskite Light-emitting Diodes”, Adv. Funct. Mater.(IF = 18.5), 2025.01
2. Do-Hyun Kwak , Seung-Beom Cho , Chang-Xu Li , Dong-Hwan Kim , Il-Kyu Park *, “Mild Oxygen Plasma-treated Nickel Oxides for Performance Enhancement of Hybrid Perovskite Light-emitting Diodes”, Vacuum (IF = 4.5), 2024.01
3. Chang-Xu Li, Seung-Bum Cho, Sang-Hyun Sohn, Do-Hyun Kwak, and Il-Kyu Park*, “Full-Color Gamut White Light Emission from Mn-doped Cs₃Cu₂X₅ Nanocrystals via Lattice Engineering”, Small (IF = 13.5), 2025.02
4. Seung-Beom Cho, Chang-Xu Li, Do-Hyun Kwak, Yu-Na Choi, and Il-Kyu Park*, “Strain Modulation and Defect Passivation in Blue-Emitting Quasi-2D Perovskites via Lewis Base Addition”, ", Chem. Eng. J. I/F=13.4,, 2025.02 Under Review
5. Yu-Na Choi, Seung-Beom Cho, Chang-Xu Li, Do-Hyun Kwak and Il-Kyu Park*, “Near Unity Quantum Yield of Strongly-Confined Blue-Emitting CsPbBr₃ Quantum Dots via Lewis Base Phosphide Ligand Passivation”, J. Alloy. Compd., I/F=5.8, (2025) Under Review
Awards
1. Best Award, 2025 Engineering Graduation Exhibition, Seoul National University of Science & Technology, 20th Feb. 2025.
2. Encouragement Award, 2018 The Korean Reliability Society Student Project Competition, 25thNov. 2022.
Language Proficiency
- OPIc (English) - Intermediate High (IH), 2024.07
Timeline
Perovskite Compositional Modification for TFTs
12.2024 - Current
FTO Electrode Pattern Precision Optimization
11.2024 - Current
Multifunctional Additive Process Optimization
01.2024 - 01.2025
ALD-based Tandem PeLED CGL Fabrication
03.2023 - 11.2024
O₂ Plasma-based Interface Defect Passivation
01.2023 - 01.2024
Master of Science - Materials Science & Engineering
Seoultech
Minor - Semiconductor Convergence Engineering
Seoultech
Bachelor of Science - Materials Science And Engineering
Seoultech
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