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Kim J, Lee K, Kim S, Sohn BH. Orientation and stretching of supracolloidal chains of diblock copolymer micelles by spin-coating process. Nanoscale 2024. [PMID: 38739015 DOI: 10.1039/d4nr00663a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
Supracolloidal chains consisting of nano- or micro-scale particles exhibit anisotropic properties not observed in individual particles. The orientation of the chains is necessary to manifest such characteristics on a macroscopic scale. In this study, we demonstrate the orientation of supracolloidal chains composed of nano-scale micelles of a diblock copolymer through spin-coating. We observed separate chains coated on a substrate with electron microscopy, and analyzed the orientation and stretching of the chains quantitatively with image analysis software. In drop-casting, the chains were coated randomly with no preferred orientation, and the degree of stretching exhibited an intrinsic semi-flexible nature. In contrast, spin-coated chains were aligned in the radial direction, and the apparent persistence length of the chain increased, confirming the stretching of the chain quantitatively. Furthermore, by incorporating fluorophores into supracolloidal chains and confirming the oriented chains with confocal fluorescence microscopy, it is demonstrated that oriented chains can be utilized as a template to align functional materials.
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Affiliation(s)
- Jaemin Kim
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea.
| | - Kyunghyeon Lee
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea.
| | - Sangyoon Kim
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea.
| | - Byeong-Hyeok Sohn
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea.
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2
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Lee K, Sohn BH. Step-growth polymerization of supracolloidal chains from patchy micelles of diblock copolymers. J Colloid Interface Sci 2023; 648:727-735. [PMID: 37321092 DOI: 10.1016/j.jcis.2023.06.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/24/2023] [Accepted: 06/05/2023] [Indexed: 06/17/2023]
Abstract
HYPOTHESIS The formation of supracolloidal chains from the patchy micelles of diblock copolymers bears a close resemblance to traditional step-growth polymerization of difunctional monomers in many aspects, including chain-length evolution, size distribution, and initial-concentration dependence. Thus, understanding the colloidal polymerization based on the step-growth mechanism can offer potential control over the formation of supracolloidal chains in terms of chain structure and reaction rate. EXPERIMENTS We analyzed the size evolution of supracolloidal chains of patchy micelles of PS-b-P4VP by investigating a large number of colloidal chains visualized in SEM images. We varied the initial concentration of patchy micelles to achieve a high degree of polymerization and a cyclic chain. To manipulate the polymerization rate, we also changed the ratio of water to DMF and adjusted the patch size by employing PS(25)-b-P4VP(7) and PS(145)-b-P4VP(40). FINDINGS We confirmed the step-growth mechanism for the formation supracolloidal chains from patchy micelles of PS-b-P4VP. Based on this mechanism, we were able to achieve a high degree of polymerization early in the reaction by increasing the initial concentration and form cyclic chains by diluting the solution. We also accelerated colloidal polymerization by increasing the ratio of water to DMF in the solution and patch size by using PS-b-P4VP with a larger molecular weight.
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Affiliation(s)
- Kyunghyeon Lee
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Byeong-Hyeok Sohn
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea.
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3
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Kim G, Kim HM, Kumar P, Rahaman M, Stevens CE, Jeon J, Jo K, Kim KH, Trainor N, Zhu H, Sohn BH, Stach EA, Hendrickson JR, Glavin NR, Suh J, Redwing JM, Jariwala D. High-Density, Localized Quantum Emitters in Strained 2D Semiconductors. ACS Nano 2022; 16:9651-9659. [PMID: 35621266 DOI: 10.1021/acsnano.2c02974] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Two-dimensional chalcogenide semiconductors have recently emerged as a host material for quantum emitters of single photons. While several reports on defect- and strain-induced single-photon emission from 2D chalcogenides exist, a bottom-up, lithography-free approach to producing a high density of emitters remains elusive. Further, the physical properties of quantum emission in the case of strained 2D semiconductors are far from being understood. Here, we demonstrate a bottom-up, scalable, and lithography-free approach for creating large areas of localized emitters with high density (∼150 emitters/um2) in a WSe2 monolayer. We induce strain inside the WSe2 monolayer with high spatial density by conformally placing the WSe2 monolayer over a uniform array of Pt nanoparticles with a size of 10 nm. Cryogenic, time-resolved, and gate-tunable luminescence measurements combined with near-field luminescence spectroscopy suggest the formation of localized states in strained regions that emit single photons with a high spatial density. Our approach of using a metal nanoparticle array to generate a high density of strained quantum emitters will be applied to scalable, tunable, and versatile quantum light sources.
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Affiliation(s)
- Gwangwoo Kim
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Hyong Min Kim
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Pawan Kumar
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Mahfujur Rahaman
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Christopher E Stevens
- Air Force Research Laboratory, Sensors Directorate, Wright-Patterson Air Force Base, Ohio 45433, United States
- KBR Inc., Beavercreek, Ohio 45431, United States
| | - Jonghyuk Jeon
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Kiyoung Jo
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Kwan-Ho Kim
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Nicholas Trainor
- 2D Crystal Consortium-Materials Innovation Platform, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Haoyue Zhu
- 2D Crystal Consortium-Materials Innovation Platform, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Byeong-Hyeok Sohn
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Eric A Stach
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Joshua R Hendrickson
- Air Force Research Laboratory, Sensors Directorate, Wright-Patterson Air Force Base, Ohio 45433, United States
| | - Nicholas R Glavin
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433, United States
| | - Joonki Suh
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Joan M Redwing
- 2D Crystal Consortium-Materials Innovation Platform, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Deep Jariwala
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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Jeon J, Kang H, Lee K, Sohn BH. Patch formation on diblock copolymer micelles confined in templates for inducing patch orientation and cyclic colloidal molecules. J Colloid Interface Sci 2022; 616:813-822. [PMID: 35248968 DOI: 10.1016/j.jcis.2022.02.099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 02/17/2022] [Accepted: 02/21/2022] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Chemically or physically distinct patches can be induced on the micelles of amphiphilic block copolymers, which facilitate directional binding for the creation of hierarchical structures. Hence, control over the direction of patches on the micelles is a crucial factor to attain the directionality on the interactions between the micelles, particularly for generating colloidal molecules mimicking the symmetry of molecular structures. We hypothesized that direction and combination of the patches could be controlled by physical confinement of the micelles. EXPERIMENTS We first confined spherical micelles of diblock copolymers in topographic templates fabricated from nanopatterns of block copolymers by adjusting the coating conditions. Then, patch formation was conducted on the confined micelles by exposing them with a core-favorable solvent. Microscopic techniques of SEM, TEM, and AFM were employed to investigate directions of patches and structures of combined micelles in the template. FINDINGS The orientation of the patches on the micelles was guided by the physical confinement of the micelles in linear trenches. In addition, by confining the micelles in a circular hole, we obtained a specific polygon arrangement of the micelles depending on the number of micelles in the hole, which enabled the formation of cyclic colloidal molecules consisting of micelles.
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Affiliation(s)
- Jonghyuk Jeon
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Heejung Kang
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Kyunghyeon Lee
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Byeong-Hyeok Sohn
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea.
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Lee K, Kim JY, Sohn BH. White-emitting film of diblock copolymer micelles with perovskite nanocrystals. RSC Adv 2022; 12:6389-6395. [PMID: 35424613 PMCID: PMC8982081 DOI: 10.1039/d2ra00098a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 02/17/2022] [Indexed: 11/21/2022] Open
Abstract
Perovskite nanocrystals are synthesized in diblock copolymer micelles to improve their processability and stability. The copolymer micelle approach allows fluorescence from a stretchable or flexible substrate by coating processes, and stable emission in water by protecting the nanocrystals in the micelles. Fluorescent films in three primary colors of blue, green, and red are also produced with the assistance of anion exchange reactions for perovskite nanocrystals in the micelles. Then, by stacking films in three primary colors, we are able to produce a white-emitting film of copolymer micelles containing only perovskite nanocrystals without the support of other kinds of emissive materials. A white-emitting film is produced by stacking films in three primary colors of diblock copolymer micelles containing perovskite nanocrystals without the support of other kinds of emissive materials.![]()
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Affiliation(s)
- Kyunghyeon Lee
- Department of Chemistry, Seoul National University Seoul 08826 Republic of Korea +82-2-889-1568 +82-2-883-2154
| | - Joon Young Kim
- Department of Chemistry, Seoul National University Seoul 08826 Republic of Korea +82-2-889-1568 +82-2-883-2154
| | - Byeong-Hyeok Sohn
- Department of Chemistry, Seoul National University Seoul 08826 Republic of Korea +82-2-889-1568 +82-2-883-2154
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Lee K, Kim JY, Kim K, Jeon J, Kang H, Sohn BH. Porous self-supporting film of semi-flexible supracolloidal chains of diblock copolymer micelles. J Colloid Interface Sci 2021; 600:804-810. [PMID: 34052531 DOI: 10.1016/j.jcis.2021.05.077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/10/2021] [Accepted: 05/13/2021] [Indexed: 11/25/2022]
Abstract
Patchy micelles of diblock copolymers can be polymerized into a linear supracolloidal chain. We measure the persistence and contour lengths of supracolloidal chains coated on a solid substrate to evaluate their flexibility. Based on the analysis, the chain is semi-flexible, and the conformation is suitably explained by the worm-like chain model. In addition, utilizing a spin-coating technique with the semi-flexible nature of the chains, we produce a self-supporting film of supracolloidal chains having nanoscale pores essentially from colloidal constituents that tend to form dense packing if there is no prior organization of them into a semi-flexible chain.
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Affiliation(s)
- Kyunghyeon Lee
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Joon Young Kim
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Kyungtae Kim
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Jonghyuk Jeon
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Heejung Kang
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Byeong-Hyeok Sohn
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea.
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Kang H, Kim K, Sohn BH. Shearing with solvent vapor annealing on block copolymer thin films for templates with macroscopically aligned nanodomains. Nanotechnology 2020; 31:455302. [PMID: 32702675 DOI: 10.1088/1361-6528/aba8bf] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A template with macroscopically aligned nanopatterns can be an effective vehicle for arranging nanoscale particles or rods in a particular orientation to achieve their anisotropic properties. A room-temperature process is also desirable for nanoscale patterning of heat-sensitive functional molecules such as organic fluorophores. Here, large-area orientation of nanodomains of block copolymers is demonstrated by simultaneous shearing and solvent vapor annealing at room temperature. The shear-aligned nanodomains are applied to a chemical template for nanoscale patterning of green fluorescent molecules. In addition, the grooved nanochannels obtained from the macroscopically aligned nanodomains work as a physical template for guiding Au nanorods to end-to-end assemblies which exhibit the polarization-dependent plasmonic extinction.
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Affiliation(s)
- Heejung Kang
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
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8
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Kim G, Ma KY, Park M, Kim M, Jeon J, Song J, Barrios-Vargas JE, Sato Y, Lin YC, Suenaga K, Roche S, Yoo S, Sohn BH, Jeon S, Shin HS. Blue emission at atomically sharp 1D heterojunctions between graphene and h-BN. Nat Commun 2020; 11:5359. [PMID: 33097718 PMCID: PMC7585426 DOI: 10.1038/s41467-020-19181-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 10/01/2020] [Indexed: 11/09/2022] Open
Abstract
Atomically sharp heterojunctions in lateral two-dimensional heterostructures can provide the narrowest one-dimensional functionalities driven by unusual interfacial electronic states. For instance, the highly controlled growth of patchworks of graphene and hexagonal boron nitride (h-BN) would be a potential platform to explore unknown electronic, thermal, spin or optoelectronic property. However, to date, the possible emergence of physical properties and functionalities monitored by the interfaces between metallic graphene and insulating h-BN remains largely unexplored. Here, we demonstrate a blue emitting atomic-resolved heterojunction between graphene and h-BN. Such emission is tentatively attributed to localized energy states formed at the disordered boundaries of h-BN and graphene. The weak blue emission at the heterojunctions in simple in-plane heterostructures of h-BN and graphene can be enhanced by increasing the density of the interface in graphene quantum dots array embedded in the h-BN monolayer. This work suggests that the narrowest, atomically resolved heterojunctions of in-plane two-dimensional heterostructures provides a future playground for optoelectronics. Here, the authors explore the blue photoluminescence signal arising from the interface between graphene and h-BN arranged in in-plane heterostructures, and fabricate a blue light emitting device utilizing the heterojunction as the emitting layer.
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Affiliation(s)
- Gwangwoo Kim
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Kyung Yeol Ma
- Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Minsu Park
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Minsu Kim
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jonghyuk Jeon
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jinouk Song
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | | | - Yuta Sato
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, 305-8565, Japan
| | - Yung-Chang Lin
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, 305-8565, Japan
| | - Kazu Suenaga
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, 305-8565, Japan
| | - Stephan Roche
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, 08193, Barcelona, Spain.,ICREA-Institució Catalana de Recerca i Estudis Avançats, 08010, Barcelona, Spain
| | - Seunghyup Yoo
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Byeong-Hyeok Sohn
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
| | - Seokwoo Jeon
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Hyeon Suk Shin
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea. .,Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea. .,Low Dimensional Carbon Material Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
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9
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Kim KS, Kim JH, Yoo SI, Sohn BH. Fluorescence Resonance Energy Transfer within Diblock Copolymer Micelles in the Proximity of Metal Nanoparticles. Macromol Res 2019. [DOI: 10.1007/s13233-019-7127-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Kim G, Kim SS, Jeon J, Yoon SI, Hong S, Cho YJ, Misra A, Ozdemir S, Yin J, Ghazaryan D, Holwill M, Mishchenko A, Andreeva DV, Kim YJ, Jeong HY, Jang AR, Chung HJ, Geim AK, Novoselov KS, Sohn BH, Shin HS. Author Correction: Planar and van der Waals heterostructures for vertical tunnelling single electron transistors. Nat Commun 2019; 10:987. [PMID: 30804336 PMCID: PMC6389964 DOI: 10.1038/s41467-019-08910-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The original version of this Article contained an error in the spelling of the author Matthew Holwill, which was incorrectly given as Mathew Holwill. This has now been corrected in both the PDF and HTML versions of the Article.
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Affiliation(s)
- Gwangwoo Kim
- Department of Energy Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Sung-Soo Kim
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea.,Carbon Composite Materials Research Center, Korea Institute of Science and Technology (KIST), Wanju, 55324, Republic of Korea
| | - Jonghyuk Jeon
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
| | - Seong In Yoon
- Department of Energy Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Seokmo Hong
- Department of Chemistry, UNIST, Ulsan, 44919, Republic of Korea
| | - Young Jin Cho
- Department of Physics, Konkuk University, Seoul, 05029, Republic of Korea
| | - Abhishek Misra
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom.,Department of Physics, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Servet Ozdemir
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Jun Yin
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Davit Ghazaryan
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom.,Department of Physics, National Research University Higher School of Economics, Staraya Basmannaya 21/4, Moscow, 105066, Russian Federation
| | - Matthew Holwill
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Artem Mishchenko
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Daria V Andreeva
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Yong-Jin Kim
- Center for Multidimensional Carbon Materials, Institute of Basic Science (IBS), Ulsan, 44919, Republic of Korea
| | - Hu Young Jeong
- UNIST Central Research Facilities (UCRF), UNIST, Ulsan, 44919, Republic of Korea
| | - A-Rang Jang
- Department of Energy Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan, 44919, Republic of Korea.,Department of Chemistry, UNIST, Ulsan, 44919, Republic of Korea
| | - Hyun-Jong Chung
- Department of Physics, Konkuk University, Seoul, 05029, Republic of Korea
| | - Andre K Geim
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Kostya S Novoselov
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom.
| | - Byeong-Hyeok Sohn
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea.
| | - Hyeon Suk Shin
- Department of Energy Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan, 44919, Republic of Korea. .,Department of Chemistry, UNIST, Ulsan, 44919, Republic of Korea. .,Center for Multidimensional Carbon Materials, Institute of Basic Science (IBS), Ulsan, 44919, Republic of Korea. .,Low Dimensional Carbon Material Center, UNIST, Ulsan, 44919, Republic of Korea.
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11
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Kim G, Kim SS, Jeon J, Yoon SI, Hong S, Cho YJ, Misra A, Ozdemir S, Yin J, Ghazaryan D, Holwill M, Mishchenko A, Andreeva DV, Kim YJ, Jeong HY, Jang AR, Chung HJ, Geim AK, Novoselov KS, Sohn BH, Shin HS. Planar and van der Waals heterostructures for vertical tunnelling single electron transistors. Nat Commun 2019; 10:230. [PMID: 30651554 PMCID: PMC6335417 DOI: 10.1038/s41467-018-08227-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 12/23/2018] [Indexed: 11/09/2022] Open
Abstract
Despite a rich choice of two-dimensional materials, which exists these days, heterostructures, both vertical (van der Waals) and in-plane, offer an unprecedented control over the properties and functionalities of the resulted structures. Thus, planar heterostructures allow p-n junctions between different two-dimensional semiconductors and graphene nanoribbons with well-defined edges; and vertical heterostructures resulted in the observation of superconductivity in purely carbon-based systems and realisation of vertical tunnelling transistors. Here we demonstrate simultaneous use of in-plane and van der Waals heterostructures to build vertical single electron tunnelling transistors. We grow graphene quantum dots inside the matrix of hexagonal boron nitride, which allows a dramatic reduction of the number of localised states along the perimeter of the quantum dots. The use of hexagonal boron nitride tunnel barriers as contacts to the graphene quantum dots make our transistors reproducible and not dependent on the localised states, opening even larger flexibility when designing future devices.
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Affiliation(s)
- Gwangwoo Kim
- Department of Energy Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Sung-Soo Kim
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea.,Carbon Composite Materials Research Center, Korea Institute of Science and Technology (KIST), Wanju, 55324, Republic of Korea
| | - Jonghyuk Jeon
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
| | - Seong In Yoon
- Department of Energy Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Seokmo Hong
- Department of Chemistry, UNIST, Ulsan, 44919, Republic of Korea
| | - Young Jin Cho
- Department of Physics, Konkuk University, Seoul, 05029, Republic of Korea
| | - Abhishek Misra
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom.,Department of Physics, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Servet Ozdemir
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Jun Yin
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Davit Ghazaryan
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom.,Department of Physics, National Research University Higher School of Economics, Staraya Basmannaya 21/4, Moscow, 105066, Russian Federation
| | - Matthew Holwill
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Artem Mishchenko
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Daria V Andreeva
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Yong-Jin Kim
- Center for Multidimensional Carbon Materials, Institute of Basic Science (IBS), Ulsan, 44919, Republic of Korea
| | - Hu Young Jeong
- UNIST Central Research Facilities (UCRF), UNIST, Ulsan, 44919, Republic of Korea
| | - A-Rang Jang
- Department of Energy Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan, 44919, Republic of Korea.,Department of Chemistry, UNIST, Ulsan, 44919, Republic of Korea
| | - Hyun-Jong Chung
- Department of Physics, Konkuk University, Seoul, 05029, Republic of Korea
| | - Andre K Geim
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Kostya S Novoselov
- School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom.
| | - Byeong-Hyeok Sohn
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea.
| | - Hyeon Suk Shin
- Department of Energy Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan, 44919, Republic of Korea. .,Department of Chemistry, UNIST, Ulsan, 44919, Republic of Korea. .,Center for Multidimensional Carbon Materials, Institute of Basic Science (IBS), Ulsan, 44919, Republic of Korea. .,Low Dimensional Carbon Material Center, UNIST, Ulsan, 44919, Republic of Korea.
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12
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Kim KS, Yoo SI, Sohn BH. Metal-Coupled Fluorescence Resonance Energy Transfer in Layer-by-Layer Assemblies for Dual Modality Fluorescence Enhancement. MACROMOL CHEM PHYS 2018. [DOI: 10.1002/macp.201800115] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Ki-Se Kim
- Department of Chemistry; Seoul National University; Seoul 08826 Republic of Korea
| | - Seong Il Yoo
- Department of Polymer Engineering; Pukyong National University; Busan 48547 Republic of Korea
| | - Byeong-Hyeok Sohn
- Department of Chemistry; Seoul National University; Seoul 08826 Republic of Korea
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13
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Kim K, Jang S, Jeon J, Kang D, Sohn BH. Fluorescent Supracolloidal Chains of Patchy Micelles of Diblock Copolymers Functionalized with Fluorophores. Langmuir 2018; 34:4634-4639. [PMID: 29597351 DOI: 10.1021/acs.langmuir.8b00375] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
By selective attachment of fluorescent dyes to the core-forming block, we produced patchy micelles of diblock copolymers with fluorophores localized in the micellar cores. From these patchy micelles functionalized with dyes, fluorescent supracolloidal chains in a few micrometers were polymerized by combining the patches in neighboring micelles, indicating that selective modification of the core-forming block delivered the functionality into the supracolloidal chain without altering the polymerization of patchy micelles. Thus, with the same polymerization condition, we were able to produce red-, green-, and blue-emitting supracolloidal chains by varying the fluorescent dyes attached to the core-forming block. In addition, we directly visualized individual supracolloidal chains by fluorescence confocal microscopy as well as by transmission electron microscopy.
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Affiliation(s)
- Kyungtae Kim
- Department of Chemistry , Seoul National University , Seoul 08826 , Republic of Korea
| | - Sukwoo Jang
- Department of Chemistry , Seoul National University , Seoul 08826 , Republic of Korea
| | - Jonghyuk Jeon
- Department of Chemistry , Seoul National University , Seoul 08826 , Republic of Korea
| | - Donghwi Kang
- Department of Chemistry , Seoul National University , Seoul 08826 , Republic of Korea
| | - Byeong-Hyeok Sohn
- Department of Chemistry , Seoul National University , Seoul 08826 , Republic of Korea
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14
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Jang S, Kim K, Jeon J, Kang D, Sohn BH. Supracolloidal chains of patchy micelles of diblock copolymers with in situ synthesized nanoparticles. Soft Matter 2017; 13:6756-6760. [PMID: 28937168 DOI: 10.1039/c7sm01497j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Supracolloidal chains of diblock copolymer micelles were functionalized with gold and silver nanoparticles (NPs). Both NPs were independently synthesized in situ in the core of spherical micelles which were then converted to patchy micelles. With these patchy micelles as colloidal monomers, supracolloidal chains were polymerized by combining the patches of neighboring micelles. Since all micelles contained NPs, NPs were incorporated in every repeat unit of chains. In addition, a single gold NP was synthesized in the micellar core in contrast to several silver NPs so that we differentiated the chains with Au NPs from those with Ag NPs by the number of NPs in the repeat unit as well as by plasmonic bands in UV-Vis spectra.
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Affiliation(s)
- Sukwoo Jang
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea.
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15
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Kim SS, Kang D, Sohn BH. Fabrication of size-controlled nanoring arrays by selective incorporation of ionic liquids in diblock copolymer micellar cores. Nanotechnology 2017; 28:225303. [PMID: 28443831 DOI: 10.1088/1361-6528/aa6f81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report the synthesis of arrayed nanorings with tunable physical dimensions from thin films of polystyrene-block-poly(4-vinylpyridine) (PS-P4VP) micelles. For accurate control of the inner and outer diameters of the nanorings, we added imidazolium-based ionic liquids (ILs) into the micellar solution, which were eventually incorporated into the micellar cores. We observed the structural changes of the micellar cores coated on a substrate due to the presence of ILs. The spin-coated micellar cores were treated with an acidic precursor solution and generated toroid nanostructures, of which size depended on the amount of IL loaded into the micelles. We then treated the transformed micellar films with oxygen plasma to produce arrays of various metal and oxide nanorings on a substrate. The spacings and diameters of nanorings were governed by the molecular weight of the PS-P4VP and the amount of IL used. We also demonstrated that arrayed Pt nanorings enabled the fabrication of reduced graphene oxide anti-nanoring arrays via a catalytic tailoring process.
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16
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Seo MS, Jeong I, Park JS, Lee J, Han IK, Lee WI, Son HJ, Sohn BH, Ko MJ. Vertically aligned nanostructured TiO2 photoelectrodes for high efficiency perovskite solar cells via a block copolymer template approach. Nanoscale 2016; 8:11472-11479. [PMID: 27195519 DOI: 10.1039/c6nr01010e] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We fabricated perovskite solar cells with enhanced device efficiency based on vertically oriented TiO2 nanostructures using a nanoporous template of block copolymers (BCPs). The dimension and shape controllability of the nanopores of the BCP template allowed for the construction of one-dimensional (1-D) TiO2 nanorods and two-dimensional (2-D) TiO2 nanowalls. The TiO2 nanorod-based perovskite solar cells showed a more efficient charge separation and a lower charge recombination, leading to better performance compared to TiO2 nanowall-based solar cells. The best solar cells employing 1-D TiO2 nanorods showed an efficiency of 15.5% with VOC = 1.02 V, JSC = 20.0 mA cm(-2) and fill factor = 76.1%. Thus, TiO2 nanostructures fabricated from BCP nanotemplates could be applied to the preparation of electron transport layers for improving the efficiency of perovskite solar cells.
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Affiliation(s)
- Myung-Seok Seo
- Photo-Electronic Hybrids Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea. and Department of Chemistry, Seoul National University, Seoul 08826, Korea.
| | - Inyoung Jeong
- Photo-Electronic Hybrids Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea. and Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Kyungbuk 37673, Korea
| | - Joon-Suh Park
- Materials and Life Science Research Division, Nanophotonics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Jinwoo Lee
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Kyungbuk 37673, Korea
| | - Il Ki Han
- Materials and Life Science Research Division, Nanophotonics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Wan In Lee
- Department of Chemistry and Chemical Engineering, Inha University, Incheon 22201, Korea
| | - Hae Jung Son
- Photo-Electronic Hybrids Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.
| | - Byeong-Hyeok Sohn
- Department of Chemistry, Seoul National University, Seoul 08826, Korea.
| | - Min Jae Ko
- Photo-Electronic Hybrids Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea. and KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea
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17
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Kim SH, Kim KS, Char K, Yoo SI, Sohn BH. Short-range ordered photonic structures of lamellae-forming diblock copolymers for excitation-regulated fluorescence enhancement. Nanoscale 2016; 8:10823-10831. [PMID: 27168228 DOI: 10.1039/c6nr00345a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Photonic crystals can be represented by periodic nanostructures with alternating refractive indices, which create artificial stop bands with the appearance of colors. In this regard, nanodomains of block copolymers and the corresponding structural colors have been intensively studied in the past. However, the practical application of photonic crystals of block copolymers has been limited to a large degree because of the presence of large defects and grain boundaries in the nanodomains of block copolymers. The present study focuses on the alternative opportunity of short-range ordered nanodomains of block copolymers for fluorescence enhancement, which also has a direct relevance to the development of fluorescence sensors or detectors. The enhancement mechanism was found to be interconnected with the excitation process rather than the alternation of the decay kinetics. In particular, we demonstrate that randomly oriented, but regular grains of lamellae of polystyrene-block-polyisoprene, PS-b-PI, diblock copolymers and their blend with PS homopolymers can behave as Bragg mirrors to induce multiple reflections of the excitation source inside the photonic structures. This process in turn significantly increases the effective absorption of the given fluorophores inside the polymeric photonic structures to amplify the fluorescence signal.
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Affiliation(s)
- Se Hee Kim
- Interdisciplinary Program in Nano Science and Technology, Seoul National University, Seoul, 151-747, Korea
| | - Ki-Se Kim
- Department of Chemistry, Seoul National University, Seoul, 151-747, Korea.
| | - Kookheon Char
- School of Chemical and Biological Engineering, The National Creative Research Initiative Center for Intelligent Hybrids, Seoul National University, Seoul, 151-747, Korea.
| | - Seong Il Yoo
- Department of Polymer Engineering, Pukyong National University, Busan 608-739, Korea.
| | - Byeong-Hyeok Sohn
- Department of Chemistry, Seoul National University, Seoul, 151-747, Korea.
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18
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Lee S, Jang S, Kim K, Jeon J, Kim SS, Sohn BH. Branched and crosslinked supracolloidal chains with diblock copolymer micelles having three well-defined patches. Chem Commun (Camb) 2016; 52:9430-3. [DOI: 10.1039/c6cc04994j] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report controlled branching and eventual crosslinking in supracolloidal chains by introducing well-defined trifunctional patchy micelles.
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Affiliation(s)
- Sanghwa Lee
- Department of Chemistry
- Seoul National University
- Seoul
- Korea
| | - Sukwoo Jang
- Department of Chemistry
- Seoul National University
- Seoul
- Korea
| | - Kyungtae Kim
- Department of Chemistry
- Seoul National University
- Seoul
- Korea
| | - Jonghyuk Jeon
- Department of Chemistry
- Seoul National University
- Seoul
- Korea
| | - Sung-Soo Kim
- Department of Chemistry
- Seoul National University
- Seoul
- Korea
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19
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Abstract
We report the construction of non-hexagonal arrays of nanoparticles by the template-assisted self-assembly of polystyrene-block-poly(4-vinylpyridine) copolymer micelles.
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Affiliation(s)
- Sung-Soo Kim
- Department of Chemistry
- Seoul National University
- Seoul 08826
- Republic of Korea
| | - Byeong-Hyeok Sohn
- Department of Chemistry
- Seoul National University
- Seoul 08826
- Republic of Korea
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20
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Abstract
We demonstrate the fabrication of fluorescent supracolloidal chains functionalized with quantum dots, which were polymerized from patched micelles of diblock copolymers by adjusting the polarity of the solvent. Supracolloidal random and block chains with green- and red-emitting quantum dots were also synthesized.
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Affiliation(s)
- Seungyong Chae
- Department of Chemistry
- Seoul National University
- Seoul
- Korea
| | - Sanghwa Lee
- Department of Chemistry
- Seoul National University
- Seoul
- Korea
| | - Kyungtae Kim
- Department of Chemistry
- Seoul National University
- Seoul
- Korea
| | - Suk Woo Jang
- Department of Chemistry
- Seoul National University
- Seoul
- Korea
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21
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Seo MS, Kim JH, Kim SS, Kang H, Sohn BH. Transferrable superhydrophobic TiO2 nanorods on reduced graphene oxide films using block copolymer templates. Nanotechnology 2015; 26:165302. [PMID: 25824622 DOI: 10.1088/0957-4484/26/16/165302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Superhydrophobic surfaces are normally fixed on the chosen materials. Here, we report transferrable superhydrophobicity which was enabled by fabricating TiO2 nanorods on a reduced graphene oxide (rGO) film. Superhydrophobic TiO2 nanorods were first synthesized from a nanoporous template of block copolymers (BCPs). The controllability over the dimension and shape of nanopores of the BCP template allowed for the adjustment of TiO2 nanostructures for superhydrophobicity. Since the rGO film provided effective transferring, TiO2 nanorods were conveyed onto a flexible polymer film and a metal substrate. Thus, the surface of the designated substrate was successfully changed to a superhydrophobic surface without alteration of its inherent characteristics.
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Affiliation(s)
- Myung-Seok Seo
- Department of Chemistry, Seoul National University, Seoul 151-747, Korea
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22
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Basché T, Bottin A, Li C, Müllen K, Kim JH, Sohn BH, Prabhakaran P, Lee KS. Energy and charge transfer in nanoscale hybrid materials. Macromol Rapid Commun 2015; 36:1026-46. [PMID: 25761127 DOI: 10.1002/marc.201400738] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Revised: 02/10/2015] [Indexed: 12/12/2022]
Abstract
Hybrid materials composed of colloidal semiconductor quantum dots and π-conjugated organic molecules and polymers have attracted continuous interest in recent years, because they may find applications in bio-sensing, photodetection, and photovoltaics. Fundamental processes occurring in these nanohybrids are light absorption and emission as well as energy and/or charge transfer between the components. For future applications it is mandatory to understand, control, and optimize the wide parameter space with respect to chemical assembly and the desired photophysical properties. Accordingly, different approaches to tackle this issue are described here. Simple organic dye molecules (Dye)/quantum dot (QD) conjugates are studied with stationary and time-resolved spectroscopy to address the dynamics of energy and ultra-fast charge transfer. Micellar as well as lamellar nanostructures derived from diblock copolymers are employed to fine-tune the energy transfer efficiency of QD donor/dye acceptor couples. Finally, the transport of charges through organic components coupled to the quantum dot surface is discussed with an emphasis on functional devices.
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Affiliation(s)
- Thomas Basché
- Institut für Physikalische Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55099, Mainz, Germany
| | - Anne Bottin
- Institut für Physikalische Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55099, Mainz, Germany
| | - Chen Li
- Max Planck-Institut für Polymerforschung, Ackermannweg 10, 55128, Mainz, Germany
| | - Klaus Müllen
- Max Planck-Institut für Polymerforschung, Ackermannweg 10, 55128, Mainz, Germany
| | - Jeong-Hee Kim
- Department of Chemistry, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul, 151-747, South Korea
| | - Byeong-Hyeok Sohn
- Department of Chemistry, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul, 151-747, South Korea
| | - Prem Prabhakaran
- Department of Advanced Materials, Hannam University, Daejeon, 305-811, South Korea
| | - Kwang-Sup Lee
- Department of Advanced Materials, Hannam University, Daejeon, 305-811, South Korea
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Lee S, Kim H, Chae S, Sohn BH. Diblock copolymer micelles as surface-functionalized particles and direct decoration of nanoparticles on their surface. POLYMER 2015. [DOI: 10.1016/j.polymer.2015.01.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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24
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Abstract
Directional attraction with lateral repulsion between colloidal nanoparticles can create their supracolloidal chains.
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Affiliation(s)
- Jeong-Hee Kim
- Department of Chemistry
- Seoul National University
- Seoul
- Korea
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25
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Abstract
We fabricated a single-layered film consisting of spherical micelles of diblock copolymers and one-dimensional Au nanorods that were surface modified with the same polymer as the corona block of the copolymers. When the diameters of micelles were larger than the lengths of the nanorods, spherical micelles arranged in a hexagonal configuration surrounded by nanorods with their long axes perpendicular to the radial direction of the micelles. This arrangement provided selective organization of the Au nanorods and Ag nanoparticles which were selectively synthesized within the cores of the copolymer micelles. Thus, position-selective arrangement of Au nanorods and Ag nanoparticles was demonstrated at the nanometer scale such that a homogenous distribution of two different nanomaterials over a large area without aggregation was achieved.
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Affiliation(s)
- Hwan Kim
- Department of Chemistry, Seoul National University, Seoul 151-747, Korea
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26
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Abstract
We report the density- and size-controlled growth of zinc oxide (ZnO) nanorod arrays on arbitrary substrates using reduced graphene oxide (rGO) nanodot arrays. For the controlled growth of the ZnO nanorod arrays, rGO nanodot arrays with tunable density and size were designed using a monolayer of diblock copolymer micelles and oxygen plasma etching. While the diameter and number density of the ZnO nanorods were readily determined by those of the rGO nanodots, the length of the ZnO nanorods was easily controlled by changing the growth time. x-ray diffraction and electron microscopy confirmed that the vertically well-aligned ZnO nanorod arrays were heteroepitaxially grown on the rGO nanodots. Strong, sharp near-band-edge emission peaks with no carbon-related peak were observed in the photoluminescence spectra, implying that the ZnO nanostructures grown on the rGO nanodots were of high optical quality and without carbon contamination. Our approach provides a general and rational route for heteroepitaxial growth of high-quality inorganic materials with tunable number density, size, and spatial arrangement on arbitrary substrates using rGO nanodot arrays.
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Affiliation(s)
- Yong-Jin Kim
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK. Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
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Chae S, Kim JH, Theato P, Zentel R, Sohn BH. Dual Functionalization of Nanostructures of Block Copolymers with Quantum Dots and Organic Fluorophores. MACROMOL CHEM PHYS 2014. [DOI: 10.1002/macp.201400007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Seungyong Chae
- Department of Chemistry; Seoul National University; Seoul 151-747 Korea
| | - Jeong-Hee Kim
- Department of Chemistry; Seoul National University; Seoul 151-747 Korea
| | - Patrick Theato
- Institute for Technical and Macromolecular Chemistry; Department of Chemistry; University of Hamburg; Hamburg D-20146 Germany
| | - Rudolf Zentel
- Institute of Organic Chemistry; Johannes Gutenberg-Universität Mainz; Mainz 55099 Germany
| | - Byeong-Hyeok Sohn
- Department of Chemistry; Seoul National University; Seoul 151-747 Korea
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28
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Abstract
Topographic nanopatterns of fluorescent cylinders with hexagonal order and in parallel lines are demonstrated with the utilization of fluorophore-functionalized diblock copolymers.
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Affiliation(s)
- Jin-Kyung Lee
- Department of Chemistry
- Seoul National University
- Seoul 151-747, Korea
| | - Heejung Kang
- Department of Chemistry
- Seoul National University
- Seoul 151-747, Korea
| | - Sanghwa Lee
- Department of Chemistry
- Seoul National University
- Seoul 151-747, Korea
| | - Inho Choi
- Department of Chemistry
- Seoul National University
- Seoul 151-747, Korea
| | - Byeong-Hyeok Sohn
- Department of Chemistry
- Seoul National University
- Seoul 151-747, Korea
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29
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Suh YJ, Lu N, Park SY, Lee TH, Lee SH, Cha DK, Lee MG, Huang J, Kim SS, Sohn BH, Kim GH, Ko MJ, Kim J, Kim MJ. Three-dimensional observation of TiO2 nanostructures by electron tomography. Micron 2013; 46:35-42. [PMID: 23313130 DOI: 10.1016/j.micron.2012.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 12/03/2012] [Accepted: 12/03/2012] [Indexed: 10/27/2022]
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Kim KS, Kim JH, Kim H, Laquai F, Arifin E, Lee JK, Yoo SI, Sohn BH. Switching off FRET in the hybrid assemblies of diblock copolymer micelles, quantum dots, and dyes by plasmonic nanoparticles. ACS Nano 2012; 6:5051-5059. [PMID: 22621410 DOI: 10.1021/nn301893e] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Recently, it has been noticed that surface plasmon resonance of metal nanoparticles can alter the intrinsic properties of nearby fluorophores. Field enhancement and radiative decay engineering are major principles for understanding a number of experimental observations such as enhanced and quenched emission of fluorophores in the vicinity of metal nanoparticles. At the same time, there are apparent similarities between surface-plasmon-coupled fluorescence and fluorescence resonance energy transfer (FRET), as both are near-field through-space interactions. From this perspective, we hypothesize that donor-acceptor interaction in the FRET can be altered by metal nanoparticles. Our approach is based on diblock copolymer micelles, which have been widely applied for nanoscale arrangement of functionalities. By applying self-assembling techniques of copolymer micelles to organize the spatial location of semiconductor quantum dots, fluorescent dyes, and metal nanoparticles, the FRET in hybrid assemblies can be switched off by plasmonic effects.
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Affiliation(s)
- Ki-Se Kim
- Department of Chemistry, Seoul National University, Seoul, 151-747, Korea
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31
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Abstract
Nanostructured graphenes such as nanoribbons, nanomeshes, and nanodots have attracted a great deal of attention in relation to graphene-based semiconductor devices. The block copolymer micellar approach is a promising bottom-up technique for generating large area nanostructures of various materials without using sophisticated electron-beam lithography. Here we demonstrate the fabrication of an array of graphene nanodots with tunable size and inter-distance with the utilization of a monolayer of diblock copolymer micelles. Au nanoparticles were synthesized in the micellar cores and effectively worked as shielding nanostructures in generating graphene nanodots by oxygen plasma etching. We also controlled the radius and inter-distance of graphene nanodots simply through the molecular weight of the copolymers.
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Affiliation(s)
- Sung-Soo Kim
- Department of Chemistry, Seoul National University, Seoul 151-747, Korea
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32
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Kim KS, Kim H, Kim JH, Kim JH, Lee CL, Laquai F, Yoo SI, Sohn BH. Correlation of micellar structures with surface-plasmon-coupled fluorescence in a strategy for fluorescence enhancement. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm35156k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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33
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Jin S, Lee Y, Jeon SM, Sohn BH, Chae WS, Lee JK. Simple fabrication of single- and multi-layer polymer nanotubes by spin-casting method within anodized aluminum oxide (AAO) templates. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm34726a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Jeon SM, Lee SH, Yoo SI, Sohn BH. Ordered complex nanostructures from bimodal self-assemblies of diblock copolymer micelles with solvent annealing. Langmuir 2011; 27:12191-12196. [PMID: 21875133 DOI: 10.1021/la202664m] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report the formation of ordered complex nanostructures from single-layered films of mixtures of polystyrene-poly(2-vinylpyridine) (PS-P2VP) and polystyrene-poly(4-vinylpyridine) (PS-P4VP) diblock copolymer micelles by THF (tetrahydrofuran) annealing. We first examined the influence of THF vapor on PS-P2VP and PS-P4VP micelles in their single-layered films. Due to the different solubility of PS-P2VP and PS-P4VP copolymers in THF, a hexagonal array of PS-P2VP micelles was changed into cylindrical nanodomains, but that of PS-P4VP micelles was not changed. The different influence of THF on PS-P2VP and PS-P4VP micelles was combined in single-layered films of mixtures of both micelles. For the purpose, we prepared mixture solutions of independently prepared small PS-P2VP and large PS-P4VP micelles. Then, bimodal self-assemblies of micelles were prepared from the mixtures, for which the hexagonal array of large PS-P4VP micelles was surrounded by small PS-P2VP micelles. When the bimodal self-assembly was annealed by THF vapor, PS-P2VP micelles were transformed into cylindrical nanodomains, but their reorganization was guided by hexagonally arranged PS-P4VP micelles. As a result, we were able to produce ordered complex nanostructures in the form of a hexagonal array of PS-P4VP micelles surrounded by PS-P2VP cylinders, which was further utilized for the synthesis of Au nanoparticles.
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Affiliation(s)
- Seung-Min Jeon
- Department of Chemistry, Seoul National University, Seoul, 151-747, Korea
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35
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Haberkorn N, Kim S, Kim KS, Sommer M, Thelakkat M, Sohn BH, Theato P. Template-Assisted Fabrication of Highly Ordered Interpenetrating Polymeric Donor/Acceptor Nanostructures for Photovoltaic Applications. MACROMOL CHEM PHYS 2011. [DOI: 10.1002/macp.201100269] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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36
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Lee JS, Kim YM, Kwon JH, Sim JS, Shin H, Sohn BH, Jia Q. Multilevel data storage memory devices based on the controlled capacitive coupling of trapped electrons. Adv Mater 2011; 23:2064-2068. [PMID: 21538583 DOI: 10.1002/adma.201004150] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 02/01/2011] [Indexed: 05/30/2023]
Affiliation(s)
- Jang-Sik Lee
- School of Advanced Materials Engineering, Kookmin University, Seoul, Korea.
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Kim KS, Yoo SI, Kim M, Sohn BH. Controlled Fluorescence Resonance Energy Transfer from Multiple Fluorophores in Layer-by-Layer Assemblies. MACROMOL CHEM PHYS 2010. [DOI: 10.1002/macp.201000309] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Jeon SM, Yoo SI, Kim KS, Kim DH, Sohn BH. Controlled fluorescence resonance energy transfer between ZnO nanoparticles and fluorophores in layer-by-layer assemblies. J Nanosci Nanotechnol 2010; 10:6819-6824. [PMID: 21137804 DOI: 10.1166/jnn.2010.2959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We controlled the fluorescence resonance energy transfer (FRET) between ZnO nanoparticles and rhodamine B (RB) within multilayered thin films prepared by the layer-by-layer (LbL) assembling method. Positively charged ZnO nanoparticles and RB-labeled poly(allyamine hydrochloride) (RB-PAH) were accurately incorporated into LbL assemblies of polyelectrolytes. The distance between ZnO nanoparticles and RB-PAH was adjusted by varying the number of layers of pure polyelectrolytes, leading to the controlled FRET from ZnO nanoparticles to RB-PAH.
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Affiliation(s)
- Sang-Mi Jeon
- Department of Chemistry, NANO Systems Institute, Seoul National University, Seoul 151-747, Korea
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Kim KS, Yoo SI, Lee TS, Sohn BH. Controlled light emission in spin-assisted layer-by-layer assemblies with fluorophores. J Nanosci Nanotechnol 2010; 10:6896-6900. [PMID: 21137820 DOI: 10.1166/jnn.2010.2964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report controlled light emissions from spin-assisted layer-by-layer (LbL) thin films containing a donor-acceptor pair of fluorescent dyes. Based on their spectral overlap, we selected rhodamine 123 (R123) and rhodamine B (RB) as the donor and acceptor, respectively. For the construction of multilayered thin films, a complex of each dye and poly(sodium 4-sulfonate) (PSS-R123 and PSS-RB) was prepared and then alternately spin coated with poly(allyamine hydrochloride) (PAH). LbL assemblies were fabricated with a sequence of [PAH/PSS-RB]/([PAH/PSS])n/[PAH/PSS-R123]. Since the distance between R123 and RB was precisely adjusted by the number of bilayers (n) of [PAH/PSS] between them, we were able to tune the light emission from the thin film by controlling the efficiency of the energy transfer.
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Affiliation(s)
- Ki-Se Kim
- Department of Chemistry, NANO System Institute, Seoul National University, Seoul 151-747, Korea
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Kim YJ, Ha SW, Jeon SM, Yoo DW, Chun SH, Sohn BH, Lee JK. Fabrication of triacetylcellulose-SiO2 nanocomposites by surface modification of silica nanoparticles. Langmuir 2010; 26:7555-7560. [PMID: 20158173 DOI: 10.1021/la904362x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We have successfully fabricated triacetylcellulose (TAC) polymer-silica nanocomposite films having up to 40 wt % of incorporated silica nanoparticles by deliberately designing a surface ligand that has a structure similar to that of polymer repeating units and effectively modifying the surface of silica nanoparticles through chemical bonding. Cross-sectional TEM analysis reveals no significant aggregation in all TAC-silica nanocomposite films. Thermal analysis results suggested that TAC-silica nanocomposites had higher T(g) and T(c) values as compared to pure TAC, and the increase in T(g) and T(c) was affected by the silica content. The transparency of all the nanocomposite films was over 80% in the visible range, confirming the excellent compatibility of nanoparticles with TAC. In this study, we enhance the interaction between nanoparticles and polymer matrices by modifying the surface of nanoparticles with a ligand that has a structure similar to that of polymer repeating units. It is expected that this method can be applied to other polymer systems to develop useful nanocomposites.
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Affiliation(s)
- Young-Jae Kim
- Department of Chemistry, Seoul National University, Seoul 151-747, Korea
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Kim CJ, Choi SJ, Ryu SW, Kim S, Chang JJ, Bae SH, Sohn BH, Choi YK. A study of the memory effects of metallic core-metal oxide shell nanocrystals by a micelle dipping technique. Nanotechnology 2010; 21:125202. [PMID: 20195009 DOI: 10.1088/0957-4484/21/12/125202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
With a simple and conformal metal nanocrystal dipping of synthesized micelles, nonvolatile memory characteristics originating from a metallic cobalt (Co) core nanocrystal (NC) surrounded by a Co-oxide shell are investigated in this study. From transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS), it was confirmed that Co-oxide was made by oxygen plasma for polymer oxidation and that metallic Co wrapped with a Co-oxide shell was made by hydrogen annealing in order to reduce the Co-oxide. Energy band diagrams considering the extent of the coexistent metallic Co/Co-oxide were also analyzed in terms of how they correspond to each program/erase/retention case. These cases were verified by electrically measured data. These results can provide a guideline for the design and optimization of metal NC embedded memory.
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Affiliation(s)
- Chung-Jin Kim
- Department of Electrical Engineering, College of Information Science and Technology KAIST, Yuseong-gu, Daejeon, Republic of Korea
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Yoo SI, Yun SH, Kim HK, Sohn BH. Highly Ordered Hexagonal Arrays of Hybridized Micelles from Bimodal Self-Assemblies of Diblock Copolymer Micelles. Macromol Rapid Commun 2010; 31:645-50. [DOI: 10.1002/marc.200900790] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 12/08/2009] [Indexed: 11/09/2022]
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Abstract
We demonstrated that anodized aluminum oxide (AAO) enables the fabrication of micellar nanotubes and nanopores decorated with nanoparticles. Block copolymer micelles containing precursors of nanoparticles were coated on the nanopores of AAO, from which we were able to select nanotubes containing nanoparticles or nanopores decorated with nanoparticles by removing the AAO template or the copolymer. Upon removal of the AAO, the micellar nanotubes with nanoparticles were produced, whereas the nanopores of AAO were decorated with nanoparticles by eliminating the copolymer. Since a variety of nanoparticles can be synthesized in addition to full control over the size and spacing of nanoparticles by the copolymer micellar approach, the methodology demonstrated here can allow fabricating functional nanotubes or nanopores with a selection of the type and size of nanoparticles.
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Affiliation(s)
- Seung-Min Jeon
- Department of Chemistry, NANO Systems Institute, Seoul National University, Seoul, Korea
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Roth PJ, Kim KS, Bae SH, Sohn BH, Theato P, Zentel R. Hetero-Telechelic Dye-Labeled Polymer for Nanoparticle Decoration. Macromol Rapid Commun 2009; 30:1274-8. [DOI: 10.1002/marc.200900254] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Revised: 05/08/2009] [Accepted: 05/11/2009] [Indexed: 11/09/2022]
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Jeon SM, Lee Y, Kim JH, Lee JK, Char K, Sohn BH. Internal morphologies of diblock copolymer nanorods fabricated from regular and irregular pores of anodized aluminum oxide templates. REACT FUNCT POLYM 2009. [DOI: 10.1016/j.reactfunctpolym.2009.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Chang JJ, Kwon JH, Yoo SI, Park C, Sohn BH. Bimodal arrays of two types of nanoparticles by mixtures of diblock copolymer micelles. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b815210a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kannaiyan D, Cha MA, Jang YH, Sohn BH, Huh J, Park C, Kim DH. Efficient photocatalytic hybrid Ag/TiO2 nanodot arrays integrated into nanopatterned block copolymer thin films. NEW J CHEM 2009. [DOI: 10.1039/b9nj00245f] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Jeon SM, Jang KY, Lee SH, Park HW, Sohn BH. Synthesis of atypical nanoparticles by the nanostructure in thin films of triblock copolymers. Langmuir 2008; 24:11137-11140. [PMID: 18729492 DOI: 10.1021/la801568g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We report the synthesis of atypical nanoparticles in donut shape with or without additional spherical nanoparticles attached on them by using the donut-like nanostructure formed in a thin film of triblock copolymers. In a high-humidity condition, a spin-coated film of triblock copolymer had donut-like holes consisting of the periphery and the center. By selective coordination of precursors of nanoparticles to the periphery of the holes, donut-like oxide nanoparticles were synthesized by oxygen plasma treatment on the film. Moreover, we were able to attach spherical nanoparticles on the donut-like nanoparticles by incorporating the other type of precursors to the center of the holes. Thus, beyond the synthesis of typical spherical nanoparticles, the results here extend potentials of the block copolymer approach to control the shape and complexity of nanoparticles.
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Affiliation(s)
- Seung-Min Jeon
- Department of Chemistry, NANO Systems Institute, Seoul National University, Seoul, Korea
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Kim S, Lee J, Jeon SM, Lee HH, Char K, Sohn BH. Orientation of Lamellar Nanostructures in the Patterned Thin Films of a Diblock Copolymer. Macromolecules 2008. [DOI: 10.1021/ma800584t] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sehee Kim
- Interdisciplinary Program in Nano Science and Technology, NANO Systems Institute, Seoul National University, Seoul 151-747, Korea; School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744, Korea; and Department of Chemistry, Seoul National University, Seoul 151-747, Korea
| | - Jiyeon Lee
- Interdisciplinary Program in Nano Science and Technology, NANO Systems Institute, Seoul National University, Seoul 151-747, Korea; School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744, Korea; and Department of Chemistry, Seoul National University, Seoul 151-747, Korea
| | - Seung-Min Jeon
- Interdisciplinary Program in Nano Science and Technology, NANO Systems Institute, Seoul National University, Seoul 151-747, Korea; School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744, Korea; and Department of Chemistry, Seoul National University, Seoul 151-747, Korea
| | - Hong H. Lee
- Interdisciplinary Program in Nano Science and Technology, NANO Systems Institute, Seoul National University, Seoul 151-747, Korea; School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744, Korea; and Department of Chemistry, Seoul National University, Seoul 151-747, Korea
| | - Kookheon Char
- Interdisciplinary Program in Nano Science and Technology, NANO Systems Institute, Seoul National University, Seoul 151-747, Korea; School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744, Korea; and Department of Chemistry, Seoul National University, Seoul 151-747, Korea
| | - Byeong-Hyeok Sohn
- Interdisciplinary Program in Nano Science and Technology, NANO Systems Institute, Seoul National University, Seoul 151-747, Korea; School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744, Korea; and Department of Chemistry, Seoul National University, Seoul 151-747, Korea
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Kim TH, Choi MS, Sohn BH, Park SY, Lyoo WS, Lee TS. Gelation-induced fluorescence enhancement of benzoxazole-based organogel and its naked-eye fluoride detection. Chem Commun (Camb) 2008:2364-6. [DOI: 10.1039/b800813b] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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