• Korean Journal of Materials Research
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• v.27 no.6
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• pp.307-311
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• 2017

Organometal halide perovskite materials, due to the tunability of their electronic and optical properties by control of composition and structure, have taken a position of significant importance in optoelectronic applications such as photovoltaic and lighting devices. Despite numerous studies on the structure - property relationship, however, practical application of these materials in electronic and optical devices is still limited by their processability during fabrication. Achieving nano-sized perovskite particles embedded in a polymer matrix with high loading density and outstanding photoluminescence performance is challenging. Here, we demonstrate that the careful control of nanoparticle formation and growth in the presence of poly(methyl methacrylate) results in perovskite nanoparticle - polymer nanocomposites with very good dispersion and photoluminescence. Furthermore, this approach is found to prevent further growth of perovskite nanoparticles, and thus results in a more uniform film, which enables fabrication using the perovskite nanoparticles.

• Transactions on Electrical and Electronic Materials
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• v.15 no.4
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• pp.193-197
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• 2014

Si-carbon composites as anode materials for lithium rechargeable batteries were prepared simply by mixing Si nanoparticles with carbon black and/or graphite through a solution process. Si nanoparticles were well dispersed and deposited on the surface of the carbon in a tetrahydrofuran solution. Si-carbon composites showed more than 700 mAh/g of initial capacity under less than 20% loading of Si nanoparticle in the composites. While the electrode with only Si nanoparticles showed fast capacity fading during continuous cycling, Si-carbon composite electrodes showed higher capacities. The cycle performances of Si nanoparticles in composites containing graphite were improved due to the role of the graphite as a matrix.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.274-274
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• 2006

Recently, conjugated polymer solar cells have attracted a great deal of attention. In this work, we applied the various scanning probe techniques to characterize composite materials typically used to fabricate polymer solar cells: poly-3(hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and P3HT/PCBM/Au nanoparticle (NP) samples. The latter is studied due to the idea of using the gold NP surface plasmon to enhance the optical absorption of the composite films. AFM is used to characterize the film morphology whereas conducting AFM is used to study the charge transport properties at the nanoscale. We found that there is a direct correlation between the nanoscale charge transport measurements and the device efficiencies.

• Membrane Journal
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• v.28 no.4
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• pp.260-264
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• 2018

Poly (ethylene oxide) (PEO)/Ag nanoparticles (AgNPs)(precursor : $AgBF_4$)/p-benzoquinone (p-BQ) composite membrane was prepared for olefin/paraffin separation. As a result, the performance of composite membrane was observed to be maintained at selectivity of 10 and permeance of 15 GPU up to 100 hours. The performance of the membrane was maintained for 100 hours was attributable to that Ag ions could be converted into stable Ag NPs by addition of p-BQ. Furthermore, the surface was partially polarized by the electron acceptor p-BQ, resulting in the formation of olefin carrier. In this study, since the cost of $AgBF_4$ used as a precursor of Ag NPs was relatively higher, $AgNO_3$ was utilized. As a result, it was confirmed that $AgNO_3$ couldn't show the stable formation of nanoparticle, resulting in the poor separation performance.

• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.1015-1020
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• 2007

A simple approach to prepare arrays of Au/TiO2 composite nanoparticles by using Au-loaded block copolymers as templates combined with a sol-gel process is described. The organic-inorganic hybrid films with closely packed inorganic nanodomains in organic matrix are produced by spin coating the mixtures of polystyrene-block-poly(ethylene oxide) (PS-b-PEO)/HAuCl4 solution and sol-gel precursor solution. After removal of the organic matrix with deep UV irradiation, arrays of Au/TiO2 composite nanoparticles with different compositions or particle sizes can be easily produced. Different photoluminescence (PL) emission spectra from an organic-inorganic hybrid film and arrays of Au/TiO2 composite nanoparticles indicate that TiO2 and Au components exist as separate state in the initial hybrid film and form composite nanoparticles after the removal of the block copolymer matrix.

• Membrane Journal
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• v.29 no.5
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• pp.246-251
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• 2019

Facilitated transport membranes using silver nanoparticles as carriers for olefin/paraffin separation have been interested. $AgBF_4$ has been used as a precursor of silver nanoparticles in previous studies. However, relatively expensive $AgBF_4$ is not suitable for commercialization, and thus, PEBAX-5513/AgNPs (precursor: $AgClO_4$)/7,7,8,8-tetracyanoquinodimethane (TCNQ) composite membranes were prepared using silver nanopaticles with relatively inexpensive $AgClO_4$ precursors. Composite membranes of various compositions were prepared for PEBAX-5513/AgNPs/TCNQ composites, but no separation performance was observed. As a result of FT-IR analysis, it was confirmed that silver nanoparticles were formed in the PEBAX-5513 polymer and the surface of Ag nanoparticles was polarized by TCNQ, but the formed silver nanoparticles were not stabilized. From these results, it was concluded that the anion of the precursor plays an important role in the olefin/paraffin separation.

• Analytical Science and Technology
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• v.20 no.5
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• pp.413-418
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• 2007

Poly(vinylpyrrolidone) stabilized cadmium sulfide (CdS) nanoparticles were loaded onto the surface of silica ($SiO_2$) nanoparticles by using ${\gamma}$-irradiation. TEM micrograph reveals the presence of ~20nm sized CdS nanoparticles on the surface of $SiO_2$ nanoparticles. XRD patterns confirm the crystalline. PL spectra of the simple PVP-stabilized CdS nanoparticle and $SiO_2$@CdS composite confirm the differences in the emission characteristics between them. Two prominent emission peaks were noted around 550 nm and 600 nm for PVP-stabilized CdS nanoparticles). The emission peaks noted for the PVP-stabilized CdS nanoparticles were found to be blue shifted for $SiO_2$@CdS composites. Besides, an additional emission peak around 450 nm was noticed for the $SiO_2$@CdS composite. The presence of CdS nanoparticles influence the emission characteristics and induce quantum confinement effect.

• Composites Research
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• v.29 no.4
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• pp.223-229
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• 2016

SiC nanoparticles were used to increase flexural properties of polymer matrix. This study was to manufacture huge concentration SiC nanoparticle/epoxy composites and to evaluate the dispersion. During mixing SiC nanoparticle and epoxy, 20 wt% SiC nanoparticle in total composites was used with both stirrer and sonication equipment together. Mixing speed and dispersion were improved with the method by using both stirrer and sonication equipment at the same time via mechanical test and FE-SEM. Based on the results, modeling of SiC nanoparticle dispersion could be established. Ultimately, unidirectional carbon fiber reinforced composites was manufactured using 20 wt% SiC nanoparticle/epoxy. Mechanical property of CFRP using dual stirrer and sonication mixing method was better than composites by single sonication mixing method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1549-1550
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• 2013

• Proceedings of the Materials Research Society of Korea Conference
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• 2008.11a
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• pp.45.1-45.1
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• 2008