• Journal of the Korean Chemical Society
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• v.57 no.5
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• pp.618-624
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• 2013

We demonstrated unique inter- and intra-plasmonic coupling effects in bimetallic Au@Ag core-shell NP arrays which are regularly or randomly arranged on self-assembled block copolymer (BCP) inverse micelle monolayers. Polyvinylpyrrolidone (PVP)-stabilized Au@Ag core-shell NP arrays in regular or disordered configuration were incorporated and assembled on reconstructed PS-b-P4VP inverse micelle templates through two types of processes. The intensively enhanced LSPR coupling properties of individual and assembled Au@Ag NPs were evaluated by UV-visible spectroscopy in terms of the type of ligand stabilizer, coupling between Au and Ag, thickness of Ag shell, and type of array configuration. Finally, Au@Ag core-shell NP arrays were employed as active substrates for surface enhanced Raman spectroscopy (SERS) and a significantly enhanced signal enhancement was observed in accordance with the coupling intensity of Au@Ag NPs patterns.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.6
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• pp.305-310
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• 2009

$TiO_2$ thin films consisting of positively charged poly (diallyldimethylammonium chloride) (PDDA) and negatively charged titanium (IV) bis (ammonium lactato) dihydroxide (TALH) were successfully fabricated on a poly (methyl methacrylate) (PMMA) by layer-by-layer (LBL) self-assembly method. By the measurement of quartz crystal microbalance (QCM), it was found that as the solution pH of TALH decreased, the deposition volume of TALH increased and the thickness of (PDDA/TALH) thin film coated on the surface of PMMA particles increased. The PMMA particles coated with the coating sequence of (PDDA/TALH)n showed the variation of color changes as a function of the number of bilayer. The number of bilayer (n) of (PDDA/TALH) thin films was 10 and 20, the values of $a^*$ and $b^*$ decreased from those of PMMA particles without coating films and the color changes was shifted to green and blue direction in the $a^*$, $b^*$ chromaticity diagram. And then, the number of n increased to 30 and 40, the values of $a^*$ and $b^*$ increased and the color changes was shifted to red and yellow direction, respectively. Finally the PMMA particles coated with $(PDDA/TALH)_{50}$ thin film showed a little same value of $a^*$ and $b^*$ with the PMMA particles without (PDDA/TALH) thin film.

• Applied Chemistry for Engineering
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• v.23 no.6
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• pp.515-520
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• 2012

In this review, the fabrication of silicon based memory capacitor and organic memory thin film transistors (TFTs) was discussed for their potential identification tag applications and biosensor applications. Metal or non-metal nanoparticles (NPs) could be capped with chemicals or biomolecules such as protein and oligo-DNA, and also be self-assembly monolayered on corresponding target biomolecules conjugated dielectric layers. The monolayered NPs were formed to be charging elements of a nano floating gate layer as forming organic memody deivces. In particular, the strong and selective binding events of the NPs through biomolecular interactions exhibited effective electrostatic phenomena in memory capacitors and TFTs formats. In addition, memory devices fabricated as organic thin film transistors (OTFTs) have been intensively introduced to facilitate organic electronics era on flexible substrates. The memory OTFTs could be applicable eventually to the development of new conceptual devices.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.162-167
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• 2018

The effect of the average particle size and shape of silver nanoparticles for the transparent conductive film (TCF) was studied. Optical and electrical properties of silver conductive lines coated on the polyethylene terephthalate (PET) film was also measured. Silver nanoparticles produced by Ag-CM, Ag-ME, Ag-EE methods showed an excellent conductivity compared to those produced by Ag-EB, Ag-CR and Ag-PL methods, but a little difference in the transparency. In the case of the former three silver nanoparticles, the average particle size was about 80 nm or less and the size was uniform. For the latter case, the severe agglomeration phenomena of particles was observed and the average particle size was 100 nm or more. This result was consistent with the result of the uniformity of the pattern shape and thickness on conductive line patterns observed by SEM. Therefore, it was confirmed that the electrical characteristics could be obtained when the average particle size of silver nanoparticles is smaller and the uniformity of the particles is maintained.