|Speaker||Prof. Hyojung Kim (Pusan National University)|
|Date||Thu. 23 May. 2019|
|Venue||#331, Asan Hall, College of Science|
Molecular Engineering for Organic Electronics and Synchrotron X-rays
We present molecular engineering for Organic Photovoltaics (OPVs) in conjugated polymer systems with fs-laser, molecular templating growth (MTG) with graphene, and solvent engineering. In case of poly(3-hexylthiophene)(P3HT) films, face-on favorable nanostructure formed by fs-laser irradiation. The dipole moment of P3HT could align along the electric field of irradiated laser, which induced face-on stacking of P3HT polymers in the films. The vertical charge current increased in the fs-laser irradiated region due the enhancement of face-on stacking. [1-4]
For the face-on favorable stacking of P3HT polymers, we adopted dry transferred graphene as a templating layer. In contrast to conventional PMMA-assisted wet transferred wet transferred graphene, dry transferred graphene is found in the current work to be quite suitable for use in the roll-to-roll process due to its lack of PMMA residue, whose removal would require high-temperature annealing. When we produce a P3HT film with a thickness of 30 nm, the face-on populations of P3HT were prominent on both the dry and wet transferred graphene layers. As the film thickness is increased to 50 nm, the face-on population decreased on the wet transferred graphene surface, but retained high levels on the dry transferred graphene.
Finally, we tried to control crystallinity of P3HT layer by solvent to form ideal BHJ (bulk heterojunction) structure in Sequential (Sq) process for OPVs. In the Sq process, a bi-layered structure is formed by the sequential deposition of the acceptor and donor layers, and the final BHJ nanostructure is formed at the interface between the layers by carrying out an additional procedure involving thermal annealing and swelling. We investigated the inter-diffusion of acceptor material at the interface in different crystalline structured layers as a function of gradual thermal annealing. We found that the P3HT films made using a low-boiling-point solvent had fewer crystalline regions and lots of amorphous regions, which enabled fullerene molecules to readily penetrate into P3HT layer within a short period of time.
We took Grazing-Incidence Wide-Angle X-ray Scattering (GIWAXS) and NEXAFS (Near Edge X-ray Absorption Fine structure) based on synchrotron x-rays for detail structural studies.
 S. Chae, K. H. Jo, S. W. Lee, H.-S. Geum, H. J. Kim, J. Choi, H. H. Lee, Macromol. Chem. Phys. 217, 537-543 (2016).
 S. Chae, A. Yi, C. M. Park, W. S. Chang, H. H. Lee, J. Choi, H. J. Kim, ACS Appl. Mater. Interfaces 9, 24422-24427 (2017).
 S. Chae, K. Jo, S. J. Won, A. Yi, J. Choi, H. H. Lee, J. H. Kim, H. J. Kim, Adv. Mater. Interfaces 4, 1701099 (2017).
 S. Chae, A. Yi, H. H. Lee, J. Choi, H. J. Kim, Journal of Materials Chemistry C (2018, in printing).
|Notice||Spring semester 2019 Seminar Schedule||-||-|
|69||[Wed. 28 Dec. 2016] Prof. James Y. Hamilton/Development of a Broad Range of Asymmetric C–C Bond Forming Reactions with a Versatile Iridium Catalyst||Prof. James Y. Hamilton||Wednesday 28 December 2016|
|68||[August 14. 2019] Principle of Semiconductor Quantum Cascade Laser and It’s Application to Chemical Gas Detection||Dr. Byeong-il Seo(Agency for Defense Development)||Wed. 14 August. 2019|
|67||[March 5. 2019] Prof. Michael J. Sailor/Treatment of S. aureus Bacterial Infections with Porous Silicon Nanoparticles||Prof. Michael J. Sailor (UC San Diego)||Tuesday. 5 March. 2019|
|66||[March 5. 2019] Innovation@Agilent||Dr. Darlene Solomon (Agilent Technologies Inc.)||Tuesday. 5 March. 2019|
|65||[October 15. 2019] A more sustainable chemistry with elemental sulfur||Dr. Thanh Binh Nguyen(Institut of Natural Product Chemistry)||Tue. 15 October. 2019|
|64||[October 10, 2017] Novel Terahertz Spectroscopies||Director Mischa Bonn||Tue, October 10, 2017|
|63||[Thu. 9 Jun. 2016] Prof. Yong-Young Noh/Development of Printed Large Area Organic Transistors and Integrated Circuits||Prof. Yong-Young Noh||Thursday 9 June 2016|
|62||[Thu. 8 Sep. 2016] Prof. Jaeyoung Sung/Stochastic chemical dynamics in living cells and its consequence for the control capacity of living cells over biological functions||Prof. Jaeyoung Sung||Thursday 8 September 2016|
|61||[Thu. 6 Oct. 2016] Prof. Young S. Park/Atomistic Molecular Engineering of Polycyclic Aromatic Hydrocarbons||Prof. Young S. Park||Thursday 6 October 2016|
|60||[Thu. 3 Nov. 2016] Prof. Min-Sik Kim/Mass spectrometry and its applications to Biological Discovery||Prof. Min-Sik Kim||Thursday 3 November 2016|
|59||[Thu. 29 Sep. 2016] Prof. Tae-Young Yoon/Observation of Single Membrane Proteins under Mechanical Tension||Prof. Tae-Young Yoon||Thursday 29 September 2016|
|58||[Thu. 26 Jun. 2016] Prof. Sung June Cho/Structural Elucidation of Novel Zeolite by Dual Space Approaches Using X-ray Powder Diffraction||Prof. Sung June Cho||Thursday 26 May 2016|
|57||[Thu. 22 Sep. 2016] Prof. Anna Lee/Organocatalyzed Asymmetric Reactions||Prof. Anna Lee||Thursday 22 September 2016|
|56||[Thu. 20 Oct. 2016] Prof. Chan Hyuk Kim/Novel Small Molecule-based Approaches for Cancer Immunotherapy||Prof. Chan Hyuk Kim||Thursday 20 October 2016|
|55||[Thu. 2 Jun. 2016] Prof. Sunkyu Han/Total Syntheses of Complex Alkaloids Inspired by Biosynthetic Hypotheses||Prof. Sunkyu Han||Thursday 2 June 2016|
|54||[Thu. 19 May. 2016] Prof. Zhuang Liu/Nanotechnology for enhanced cancer radiation therapy and immunotherapy||Prof. Zhuang Liu||Thursday 19 May 2016|
|53||[Thu. 17 Nov. 2016] Prof. Seunghoon Shin/Synthetic Methods Development based on Rational Analysis of Intermediates||Prof. Seunghoon Shin||Thursday 17 November 2016|
|52||[Thu. 1 Dec. 2016] Prof. Sang-Yong Ju/Highly Pure Carbon Nanotubes sorted by a Flavin for Thin Film Transistor Applications||Prof. Sang-Yong Ju||Thursday 1 December 2016|
|51||[May 9. 2019] Chemistry in Molecular Vessels||Prof. Partha Sarathi Mukherjee||Thu. 9 May. 2019|
|50||[Thu. 9 Mar. 2017] Prof. Woon Ju Song/Department of Chemistry, Seoul National University, Seoul, Korea||Prof. Woon Ju Song||Thu. 9 Mar. 2017|
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