visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
날짜 2017-04-28 14:30 
일시 Apr. 28 (Fri.), 02:30 PM 
장소 E6-2. 1st fl. #1323 
연사 Dr. JeongYoung Park Graduate School of EEWS, KAIST 

 

Hot electron generation at surfaces and its impact to catalysis and renewable energy conversion

 

Dr. JeongYoung Park

Graduate School of EEWS, KAIST

Apr. 28 (Fri.), 02:30 PM

E6-2. 1st fl. #1323

 

 

Abstract: 

A pulse of high kinetic energy electrons (1–3 eV) in metals can be generated after surface exposure to external energy, such as the absorption of light or exothermic chemical processes. These energetic electrons are not at thermal equilibrium with the metal atoms and are called ‘‘hot electrons’’. The detection of hot electrons and understanding the correlation between hot electron generation and surface phenomena are challenging questions in the surface science and catalysis community. Hot electron flow generated on a gold thin film by photon absorption (or internal photoemission) appears to be correlated with localized surface plasmon resonance. 

In this talk, I will show strategy to quantify the non-adiabatic energy transfer and detect hot electron flux during the elementary steps of the energy conversion process and catalytic reaction processes occurring at both of solid-gas and solid-liquid interfaces. To detect and utilize the hot electron flows, the nanodiodes consisting of metal catalyst film, semiconductor layers, and Ohmic contact pads were constructed It was shown that the chemicurrent or hot electron flows were well correlated with the turnover rate of CO oxidation or hydrogen oxidation separately measured by gas chromatography, suggesting the intrinsic relation between catalytic reaction and hot electron generation. We show a novel scheme of graphene catalytic nanodiode composed of a Pt NPs array on graphene/TiO2 Schottky nanodiode, which allows detection of hot electron flows induced by hydrogen oxidation on Pt NPs. By analyzing the correlation between the turnover rate (catalytic activity) and hot electron current (chemicurrent) measured on the graphene catalytic nanodiodes, we demonstrate that the catalytic nanodiodes utilizing a single graphene layer for electrical connection of Pt NPs are beneficial for the detection of hot electrons due to not only atomically thin nature of graphene but also reducing the height of the potential barrier existing at the Pt NPs/graphene interface. I will show that hot electron flow generated on a gold thin film by photon absorption (or internal photoemission) is amplified by localized surface plasmon resonance. Finally, The effect of surface plasmons on the catalytic and photocatalytic activity on metal–oxide hybrid nanocatalysts is also highlighted. These phenomena imply the efficient energy conversion from the photon energy to the chemical energy, with the potential application of hot electron-based photocatalytic devices.

 

 

 

번호 날짜 장소 제목
327 2017-08-31 14:00  #5318(E6-2. 5th fl.)  “Berry phase and nonlinear response: photocurrent in noncentrosymmetric insulators and Weyl semimetals” file
326 2023-06-08 16:00  E6-2, #1323  Thermal decoupling in high-Tc cuprate superconductors
325 2019-05-31 11:00  #1323, E6-2  Cavity QED with Spin Qubits file
324 2022-05-27 11:00  Online seminar  Current Status and Future Plans of ADMX file
323 2015-07-23 13:30  E4, B401  Enhanced ZnO based UV photonics and related applications file
322 2020-10-15 16:00  CAPP Seminar Room #C303, Creation Hall (3F), KAIST Munji Campus  Graphene-based Josephson junction microwave bolometer file
321 2022-06-03 11:00  E6-2 #1323  (응집물리 세미나) Theoretical Investigation of Exotic Quantum States in Low-dimensional Materials
320 2023-03-27 15:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  A coherent mechanical oscillator pumped by a suspended quantum dot file
319 2022-09-21 16:00  College of Natural Science E6-2, Rm. 1323  Materials and Device Nanofabrication of Optical Metasurfaces file
318 2023-11-01 16:00  E6-2, #2502  [High Energy Theory Seminar] Modular functions and 3D N=4 rank-zero superconformal field theories
317 2019-02-21 16:00  #5313, E6-2  B-meson charged current anomalies - Theoretical status file
316 2023-03-30 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  Detecting axions with chiral magnetic effects file
315 2019-09-18 16:00  Seminar Room #1323  Fall 2019: Physics Seminar Serises file
314 2016-03-07 16:00  E6, 1501  Physics Colloquium : 2016 Spring file
313 2023-11-15 16:00  E6-6, #119  Quantum hydrodynamic theory for plasmonics: from molecule-coupling to nonlinear optics
312 2022-10-04 16:00  E6 #2501  Distinguishing 6d (1, 0) SCFTs
311 2015-03-04 12:00  1323호, E6-2  Bioimaging and Biosensing Using Near-Infrared Fluorescence file
310 2019-05-03 11:00  E6-2. 2st fl. #2502  Exotic Magnetism file
309 2014-12-22 14:00  E6, Rm1319  Dynamics of molecular motors: Power stroke vs Brownian ratchet file
308 2019-05-30 16:00  #1323, E6-2  Tuning the excitonic properties of semiconductors with light-matter interactions file