26
|
Kim YJ, Kim SS, Park JB, Sohn BH, Yi GC. Controlled growth of inorganic nanorod arrays using graphene nanodot seed layers. NANOTECHNOLOGY 2014; 25:135609. [PMID: 24598198 DOI: 10.1088/0957-4484/25/13/135609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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.
Collapse
|
27
|
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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
28
|
Lee JK, Kang H, Lee S, Choi I, Sohn BH. Fluorescent topographic nanopatterns by fluorophore-functionalized diblock copolymers. RSC Adv 2014. [DOI: 10.1039/c4ra06139j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Topographic nanopatterns of fluorescent cylinders with hexagonal order and in parallel lines are demonstrated with the utilization of fluorophore-functionalized diblock copolymers.
Collapse
|
29
|
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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 12/03/2012] [Accepted: 12/03/2012] [Indexed: 10/27/2022]
|
30
|
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] [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.
Collapse
|
31
|
Kim SS, Choi JY, Kim K, Sohn BH. Large area tunable arrays of graphene nanodots fabricated using diblock copolymer micelles. NANOTECHNOLOGY 2012; 23:125301. [PMID: 22398242 DOI: 10.1088/0957-4484/23/12/125301] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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.
Collapse
|
32
|
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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
33
|
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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
34
|
Jeon SM, Lee SH, Yoo SI, Sohn BH. Ordered complex nanostructures from bimodal self-assemblies of diblock copolymer micelles with solvent annealing. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:12191-12196. [PMID: 21875133 DOI: 10.1021/la202664m] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [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.
Collapse
|
35
|
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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
36
|
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. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 02/01/2011] [Indexed: 05/30/2023]
|
37
|
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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
38
|
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. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 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] [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.
Collapse
|
39
|
Kim KS, Yoo SI, Lee TS, Sohn BH. Controlled light emission in spin-assisted layer-by-layer assemblies with fluorophores. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 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] [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.
Collapse
|
40
|
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 : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:7555-7560. [PMID: 20158173 DOI: 10.1021/la904362x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [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.
Collapse
|
41
|
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] [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.
Collapse
|
42
|
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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 12/08/2009] [Indexed: 11/09/2022]
|
43
|
Jeon SM, Lee SH, Sohn BH, Song O. Micellar nanotubes and AAO nanopores decorated with nanoparticles. NANOTECHNOLOGY 2009; 20:285603. [PMID: 19550012 DOI: 10.1088/0957-4484/20/28/285603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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.
Collapse
|
44
|
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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Revised: 05/08/2009] [Accepted: 05/11/2009] [Indexed: 11/09/2022]
|
45
|
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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
46
|
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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
47
|
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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
48
|
Jeon SM, Jang KY, Lee SH, Park HW, Sohn BH. Synthesis of atypical nanoparticles by the nanostructure in thin films of triblock copolymers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:11137-11140. [PMID: 18729492 DOI: 10.1021/la801568g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [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.
Collapse
|
49
|
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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
50
|
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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|