LBNL 한인 모임

Abstract: Grain boundary defectstopological defects around grain boundaries (GB)play an essential role in electrical, optical, magnetic, mechanical, and chemical properties of the polycrystalline materials. When the grain size of the materials decreases to the nanometer scale, the grain boundary defects predominantly determine those properties, opening up a variety of new applications. Although researchers have sought ways to study the contribution of specific grain boundary defects to the properties, non-uniformity in grain size and shape and random misorientation between the grains make these tasks challenging. This presentation will first discuss controlling 3D heteroepitaxy of colloidal faceted nanocrystals to grow uniform multiple grains organized into a well-defined geometry which gives a new opportunity for overcoming such limitations from the non-uniformity and randomness. Within the resulting nanocrystals, we will see that three-dimensionally patterned strain field exist in the form of disclinations and dislocations. We will then discuss how we can apply the 3D hetroepitaxy to investigate the effect of microscopic grain geometry on the macroscopic properties. For example, we can obtain a correlation between the GB defects and the catalytic property, because the patterned strain creates exact GB structure in a periodic fashion that serves as the active sites for catalysis. Lastly, we will highlight that the epitaxy-based design principles can significantly extend the library of grain structures in the nanocrystalline materials.  


Biography: Myounghwan Oh is a postdoc working in Paul Alivisatos group at UC Berkeley and is investigating the properties of the grain boundary defects in the nanocrystalline materials through high-precision control of 3D heteroepitaxy. He received his B.S. in Chemical Biological Engineering from Seoul National University (SNU), Korea, followed by a M.S. in Interdisciplinary of Nanoscience and Technology and a Ph.D. in Chemical Biological Engineering. myoung19.jpg

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공지 UKC 2014 Volunteers needed! orppaha 2014.05.28 10843
공지 LBNL 초기 정착 도우미 서비스 (LBNL Initial Settlement Assistance Service) orppaha 2013.08.01 11678
공지 KSEA Berkeley Chapter 소개 orppaha 2013.07.31 10334
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30 Operando X-ray absorption spectroscopy studies on CO electroreduction reaction (200124 KSEA Berkeley Chapter Seminar) file 지미버틀러 2020.01.30 741
29 An Overview of R&D Activities around NST, KISTI and NERSC (171213 KSEA Berkeley Chapter Seminar) file 지미버틀러 2019.04.10 777
28 3D printed absorber for capturing toxic chemotherapy drugs before they spread through the body (191101 KSEA Berkeley Chapter Seminar) file 지미버틀러 2019.11.09 798
27 Simulation studies on dynamical and structural properties of liquid state materials: From the perspective of statistical mechanics (180612 KSEA Berkeley Chapter Seminar) file 지미버틀러 2019.04.10 848
26 Development of Innovative materials and process technology: 1. Microreactors for Better Chemical Processes 2. Peptide Self-Assembly (180813 KSEA Berkeley Chapter Seminar) file 지미버틀러 2019.04.10 849
25 2018 May Happy Hour file 지미버틀러 2019.04.10 851
24 Surface and Interfacial Chemistry of Bio-inspired Phenolic Coatings (190213 KSEA Berkeley Chapter Seminar) file 지미버틀러 2019.04.11 860
23 A single-ion conducting borate network polymer as a viable electrolyte for Li-metal batteries (190410 KSEA Berkeley Chapter Seminar) file 지미버틀러 2019.04.11 883
22 Study on the chemical/electronic structures of organic functional materials by combining photoemission spectroscopy with argon gas cluster ion beam sputtering (181214 KSEA Berkeley Chapter Seminar) file 지미버틀러 2019.04.11 911
21 Unveiling the mechanism of phase evolution and H2 storage/CO2 uptake properties in nanohybride of magnesium borohydride supported by reduced graphene oxide (200124 KSEA Berkeley Chapter Seminar) file 지미버틀러 2020.01.30 922
20 2018 July Farewell Dinner for Prof. Kim and Prof. Lee file 지미버틀러 2019.04.10 938
» High Symmetry Ordered Multigrain Nanocrystals to Reveal and Maximize the Effect of Grain Boundary Defects (181018 KSEA Berkeley Chapter Seminar) file 지미버틀러 2019.04.11 975
18 Aligned carbon nanotube architectures for biomimetic metasurfaces (190807 KSEA Berkeley Chapter Seminar) file 지미버틀러 2019.08.08 1015
17 Designing (photo)electrocatalysts with consideration of its application to real device for hydrogen economy and artificial photosynthesis (180227 KSEA Berkeley Chapter Seminar) file 지미버틀러 2019.04.10 1035
16 2018 Sep. Farewell Lunch for Dr. Kim file 지미버틀러 2019.04.10 1062
15 2019 Apr. Farewell Dinner for Dr. Shin and Dr. Cho file 지미버틀러 2019.04.11 1062
14 Photo-chemistry and -physics of Ir complexes (190410 KSEA Berkeley Chapter Seminar) file 지미버틀러 2019.04.11 1114
13 Controlled self-assembly of block copolymer particles from emulsions : Combined study of experiment, theory, and simulation (171016 KSEA Berkeley Chapter Seminar) file 지미버틀러 2019.02.24 1192
12 High Throughput Evolution of Near Infrared Serotonin Nanosensors (190807 KSEA Berkeley Chapter Seminar) file 지미버틀러 2019.08.08 1296