사진

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Lee, Jun Hee (이준희)

Department
School of Energy and Chemical Engineering(에너지화학공학과)
Website
http://junhee.wix.com/qmec
Lab
Quantum Materials for Energy Conversion Lab. (에너지변환 양자물질 연구실)
Research Keywords
자성체, 강유전체, 촉매 재료, 위상, 자성, 강유전성, 수치 해석, 분자동역학, 밀도범함수이론, Quantum simulation, materials genome, Li battery, photocatalyst, fuel cell, Catalytic materials, Ferroelectrics, Magnetic materials, Ferroelectricity, Magnetism, Topology, Density Functional Theory, QUANTUM ESPRESSO, Molecular Dynamics, Numerical Analysis
Research Interests
The recently discovered orthorhombic HfO2 has prompted research to develop devices that utilize its robust ferroelectricity at reduced dimensions. HfO2 has attractive advantages compared to conventional perovskite ferroelectrics in its compatibility with Si-based CMOS (Complementary Metal-Oxide Semiconductor) technique, in addition to its scalability to thin films with substantial ferroelectric polarizations (~10nm)However, there are setbacks to devices, such as its large coercive field compared to that of conventional perovskites by one order of magnitude. The large coercive fields used to switch ferroelectric polarization can damage HfO2 films, resulting in electric breakdown and shortening their endurance. A recent research trend focuses on reducing the coercive fields using various dopants. Various factors from dopants are studied to tune the coercive fields such as volume change, the monoclinic phase fraction, and the dopant size effects. Still, the mechanism of why some elements (such as Si), significantly reduce the coercive field has not been fully understood. Hence, we explore on how to reduce the coercive field of HfO2 by substitution doping and why Si is a critical element in lowering coercive fields using first-principle simulations. Furthermore, Our laboratory plans to apply this study to the tons of ultra-dense semiconductor memory materials.
Using first-principles density functional theory calculations, we explore the chemical activity of various oxide films focusing on the oxygen evolution reaction (OER), the bottleneck of water splitting. Especially the reactivity of the surface is tuned by electric dipoles dynamically induced by the adsorbed species during the intermediate steps of the reaction while the initial and final steps remain unaffected. In order to investigate OER reaction material and mechanism, the combined effects of the dynamically induced dipoles and epitaxial strain strongly reduce rate-limiting thermodynamic barriers and significantly improve the efficiency of the reaction.
Nd2Fe14B is well known permanent magnet for its high coercive field and large magnetic moment, thereby it has been used steadily for a long time. Using DFT calculation, we will analyze how doping elements affect magnetic properties when other rare earth metal such as Tb, Ce, and Y are doped into Nd2Fe14B. Ultimately, based on these predictions, we aim to develop a permanent magnet that has better coercive field and magnetic moment but low cost.
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Issue DateTitleAuthor(s)TypeViewAltmetrics
2021-01Support structure-catalyst electroactivity relation for oxygen reduction reaction on platinum supported by two-dimensional titanium carbideLee, Yeongdae; Ahn, Jang Hyuk; Park, Hee-Young, et alARTICLE15 Support structure-catalyst electroactivity relation for oxygen reduction reaction on platinum supported by two-dimensional titanium carbide
2020-09Scale-free ferroelectricity induced by flat phonon bands in HfO2Lee, Hyun-Jae; Lee, Minseong; Lee, Kyoungjun, et alARTICLE22 Scale-free ferroelectricity induced by flat phonon bands in HfO2
2020-08Enhanced photoluminescence quantum efficiency and stability of water assisted CsPbBr3 perovskite nanocrystalsKim, Minji; Kim, Jae Ho; Kim, Maengsuk, et alARTICLE62 Enhanced photoluminescence quantum efficiency and stability of water assisted CsPbBr3 perovskite nanocrystals
2020-08Electrolyte-mediated nanograin intermetallic formation enables superionic conduction and electrode stability in rechargeable batteriesRyu, Jaegeon; Kang, Jieun; Kim, Hongju, et alARTICLE22 Electrolyte-mediated nanograin intermetallic formation enables superionic conduction and electrode stability in rechargeable batteries
2020-06Dynamic analysis of non-linear wake-up behavior in Hf0.7Zr0.3O2 thin filmChoi, J. C.; Song, M. S.; Lee, K., et alARTICLE137 Dynamic analysis of non-linear wake-up behavior in Hf0.7Zr0.3O2 thin film
2020-05Facile Ferroelectric Phase Transition Driven by Si Doping in HfO2Yang, Hyemi; Park, Kunwoo; Lee, Hyun-Jae, et alARTICLE117 Facile Ferroelectric Phase Transition Driven by Si Doping in HfO2
2020-05A catalyst design for selective electrochemical reactions: direct production of hydrogen peroxide in advanced electrochemical oxidationKo, Young-Jin; Choi, Keunsu; Yang, Boram, et alARTICLE56 A catalyst design for selective electrochemical reactions: direct production of hydrogen peroxide in advanced electrochemical oxidation
2020-04Enhancing Bifunctional Electrocatalytic Activities via Metal d-Band Center Lift Induced by Oxygen Vacancy on the Subsurface of PerovskitesLee, Hansol; Gwon, Ohhun; Choi, Keunsu, et alARTICLE47 Enhancing Bifunctional Electrocatalytic Activities via Metal d-Band Center Lift Induced by Oxygen Vacancy on the Subsurface of Perovskites
2020-03Topological superconductivity from transverse optical phonons in oxide heterostructuresLee, Minseong; Lee, Hyun-Jae; Lee, Jun Hee, et alARTICLE83 Topological superconductivity from transverse optical phonons in oxide heterostructures
2020-02Enhanced Moisture Stability by Butyldimethylsulfonium Cation in Perovskite Solar CellsKim, Bohyung; Kim, Maengsuk; Lee, Jun Hee, et alARTICLE168 Enhanced Moisture Stability by Butyldimethylsulfonium Cation in Perovskite Solar Cells
2020-01Synergetic donor-donor codoping strategy for enhanced photoelectrochemical activity of hematiteSeo, Ji Hui; Choi, Keumsu; Nam, Jisoo, et alARTICLE204 Synergetic donor-donor codoping strategy for enhanced photoelectrochemical activity of hematite
2020-01Releasing the hidden shift current in the TTF-CA organic molecular solid via symmetry loweringKim, Bumseop; Kim, Jeongwoo; Shin, Dongbin, et alARTICLE126 Releasing the hidden shift current in the TTF-CA organic molecular solid via symmetry lowering
2020-01Synergetic donor-donor codoping strategy for enhanced photoelectrochemical activity of hematiteSeo, Ji Hui; Choi, Keunsu; Nam, Jisoo, et alARTICLE8 Synergetic donor-donor codoping strategy for enhanced photoelectrochemical activity of hematite
2019-12Nonvolatile Balanced Ternary Memory Based on The Multiferroelectric Material GeSnTe2Nam, Jisoo; Lee, Hosik; Lee, Minseong, et alARTICLE117 Nonvolatile Balanced Ternary Memory Based on The Multiferroelectric Material GeSnTe2
2019-11Efficient, stable solar cells by using inherent bandgap of alpha-phase formamidinium lead iodideMin, Hanul; Kim, Maengsuk; Lee, Seung-Un, et alARTICLE163 Efficient, stable solar cells by using inherent bandgap of alpha-phase formamidinium lead iodide
2019-10Stable Subloop Behavior in Ferroelectric Si-Doped HfO2Lee, Kyoungjun; Lee, Hyun-Jae; Lee, Tae Yoon, et alARTICLE122 Stable Subloop Behavior in Ferroelectric Si-Doped HfO2
2019-09High-Output Triboelectric Nanogenerator Based on Dual Inductive and Resonance Effects-Controlled Highly Transparent Polyimide for Self-Powered Sensor Network SystemsLee, Jae Won; Jung, Sungwoo; Lee, Tae Won, et alARTICLE237 High-Output Triboelectric Nanogenerator Based on Dual Inductive and Resonance Effects-Controlled Highly Transparent Polyimide for Self-Powered Sensor Network Systems
2019-09In-situ coalesced vacancies on MoSe2 mimicking noble metal: Unprecedented Tafel reaction in hydrogen evolutionLee, Junghyun; Kim, Changmin; Choi, Keunsu, et alARTICLE267 In-situ coalesced vacancies on MoSe2 mimicking noble metal: Unprecedented Tafel reaction in hydrogen evolution
2019-08Structure-dependent catalytic properties of mesoporous cobalt oxides in furfural hydrogenationNguyen-Huy, Chinh; Lee, Jihyeon; Seo, Ji Hui, et alARTICLE348 Structure-dependent catalytic properties of mesoporous cobalt oxides in furfural hydrogenation
2019-08Magnetic field-temperature phase diagram of multiferroic (NH4)2FeCl5·H2OClune, Amanda J.; Nam, Jisoo; Lee, Minseong, et alARTICLE258 Magnetic field-temperature phase diagram of multiferroic (NH4)2FeCl5·H2O

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