• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.24 no.5
• /
• pp.427-431
• /
• 2011

Hybrid $SiO_2-TiO_2$ photoelectrode with different type of layers was investigated in dye-sensitized solar cells (DSSC). Use of a thin layer of nanocrystalline $TiO_2$ would imply reduction in the amount of dye coverage, however, lower amount of dye in the thin films would imply fewer electron generation upon illumination. So, thus, it becomes necessary to include a $SiO_2-TiO_2$ layer for increase light harvesting effect such that the lower photon conversion due to thin layer could be compensated. In this paper reports the use of transparent high surface area $TiO_2$ layer and an additional $SiO_2-TiO_2$ layer, thus ensuring adequate light harvesting in these devices. The best solar conversion efficiency 6.6% under AM 1.5 was attained with a multi-layer structure using $TiO_2$ layer/$SiO_2-TiO_2$ layer/$TiO_2$ layer for the light harvesting and this had resulted to about 44% increase in photocurrent density of dye-sensitized solar cells.

• Proceedings of the Korean Society of Dyers and Finishers Conference
• /
• 2012.03a
• /
• pp.50-50
• /
• 2012

투습방수필름으로 많이 사용되고 있는 폴리우레탄(PU)에 광촉매 기능성을 가지고 있는 나노-$TiO_2$(Degussa P25)를 1~10wt% 복합시킨 후, 은(Ag)이온 수용액에서 자외선 조사에 의한 광증착시키는 과정을 거쳐 은이 도핑된 PU/$TiO_2$/Ag 하이브리드 멤브레인 필름을 제조하였다. (주)비에스지에서 제공받은 PU/DMF/MEK 용액에 $TiO_2$를 초음파로 균일하게 분산배합한 후, 필름캐스팅하여 만든 필름을 AgNO3 수용액에 침지시키고 254nm의 자외선을 30~120초 동안 조사하는 광증착법으로 은을 환원시켜 도핑시켰다. 은 도핑된 하이브리드 필름을 Shaking flask method에서 폐렴간균, 황색포도상구균에 대한 항균성을 측정하고, Clear zone method에서 대장균에 대한 항균성을 측정한 결과, $TiO_2$ 함량이 3wt% 이상이고 UV조사시간이 60초 이상인 경우 99.9% 이상의 항균성을 나타내는 것을 확인하였다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.9
• /
• pp.2065-2070
• /
• 2010

The diluted PMMA treated $SiO_2$ films as an passivation materials for semiconductor devices was researched by using the FTIR spectra. The diluted PMMA solution with various ratios changed the surface of $SiO_2$ film as the hydrophilic, hydrophobic or hybrid type properties. The sample 7 with little carbon content showed dramatically the chemical variation by the FTIR spectra analysis. Beacuse the little carbon with electrons decreased the polarity and surface energy on the $SiO_2$ film, and then became a stable bonding structure and decreased the leakage current. The FTIR spectra can define the detail variation due to the chemical reaction on the organic thin film, and help to research the characteristic of the organic materials.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2011.05a
• /
• pp.10.2-10.2
• /
• 2011

The design and synthesis of protein-like polymers is a fundamental challenge in materials science. A biomimetic approach is to explore the impact of monomer sequence on non-natural polymer structure and function. We present the aqueous self-assembly of two peptoid polymers into extremely thin two-dimensional (2D) crystalline sheets directed by periodic amphiphilicity, electrostatic recognition and aromatic interactions. Peptoids are sequence-specific, oligo-N-substituted glycine polymers designed to mimic the structure and functionality of proteins. Mixing a 1:1 ratio of two oppositely charged peptoid 36 mers of a specific sequence in aqueous solution results in the formation of giant, free-floating sheets with only 2.7 nm thickness. Direct visualization of aligned individual peptoid chains in the sheet structure was achieved using aberration-corrected transmission electron microscopy. Specific binding of a protein to ligand-functionalized sheets was also demonstrated. The synthetic flexibility and biocompatibility of peptoids provide a flexible and robust platform for integrating functionality into defined 2D nanostructures. In the later part of my talk, we describe the use of metal ions to construct two-dimensional hybrid films that have the ability to self-heal. Incubation of biomimetic peptoid polymers with specific divalent metal ions results in the spontaneous formation of uniform multilayers at the air-water interface. We anticipate that ease of synthesis and transfer of these two-dimensional materials may have many potential applications in catalysis, gas storage and sensing, optics, nanomaterial synthesis, and environmentally responsive scaffolds.

• Journal of the Korean Ceramic Society
• /
• v.47 no.1
• /
• pp.61-65
• /
• 2010

Ultrathin atomic layer deposition (ALD) coatings were found to enhance the performance of lithium-ion batteries (LIBs). Previous studies have demonstrated that $LiCoO_2$ cathode powders coated with metal oxides with thicknesses of $\sim100-1000{\AA}$ grown using wet chemical techniques improved LIB performance. In this study, $LiCoO_2$ powders were coated with conformal $Al_2O_3$ ALD films with thicknesses of only $\sim3-4{\AA}$ established using 2 ALD cycles. The coated $LiCoO_2$ powders exhibited a capacity retention of 89% after 120 charge-discharge cycles in the 3.3~4.5 V (vs. $Li/Li^+$) range. In contrast, the bare $LiCoO_2$ powders displayed only a 45% capacity retention. This dramatic improvement may result from the ultrathin $Al_2O_3$ ALD film acting to minimize Co dissolution or to reduce surface electrolyte reactions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.181-181
• /
• 2010

Few-walled carbon nanotubes (FWNTs)-based field emitters with long term stability are fabricated by using a spray method. Tetraethylorthosilicate (TEOS) sol as a binder was mixed with dispersed solution of FWNTs to enhance the adhesion of FWNTs on the cathode substrate. Due to the strong intermolecular interaction of TEOS to the functional groups attached on CNTs and substrate, CNTs are tightly adhered to the cathode electrode when heat treatment is performed at $150^{\circ}C$ for 1 hour, resulting in a stable electron emission of CNT emitters for long time. Excellent field emission characteristics were exhibited, with a large field enhancement factor and low turn-on voltage, comparable to those of CNT emitters fabricated by a screen printing of CNT paste. Therefore, FWNTs / TEOS hybrid films could be utilized as an alternative for the efficient and reliable field emitters.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.03b
• /
• pp.13-13
• /
• 2010

Piezoelectric sensors are extensively used to measure force because of their high sensitivity and low cost. however, the development of device with reduced size but with improved sensitivity is highly important. Low-temperature co-fired ceramic (LTCC) is one of promising materials for this application than a silicon substrate because it has very good electrical and mechanical properties as well as possibility of making various three dimensional (3D) structures. In this work, piezoelectric pressure sensors based on hybrid LTCC technology were presented. The LTCC diaphragms with thickness of $400\;{\mu}m$ were fabricated by laminating 12 green tapes which consist of alumina and glass particle in an organic binder. The piezoelectric sensing layer consists of PZT thin film deposited by RF magnetron sputtering method on between top and bottom Au electrodes. The PZT films deposited on LTCC diaphragms were successfully grown and were analyzed by using X-ray diffraction method (XRD) and field emission scanning electron microscope (FESEM).

• The Research Journal of the Costume Culture
• /
• v.15 no.6
• /
• pp.1063-1077
• /
• 2007

The purpose of this research is to comprehend the various range of expressions of fantasies and to summarize the expressive effects of fantasies that appear most commonly in today's popular culture such as film and fashion. The followings are the results of the research: Fantasy means a genre of literary arts, which uses magic and supernatural figures as the themes or plots. The characteristics of the expressive effects of the costumes in fantasy movies are summarized as metaphor and symbol, hybrid, otherness, grotesque. After analyzing the costumes in fantasy movies, it is concluded that these characteristics can be conceptualized as the characteristics of the expressive effects in the field of fashion and they can be used as the basis in setting the visual images. This research also aims at recognizing and predicting the fashion trend by understanding closely at the popular cultures, using the films as a tool, which can be led to examining the possibility of combining various popular cultures.

• The Journal of the Korea Contents Association
• /
• v.5 no.5
• /
• pp.92-99
• /
• 2005

It is not easy to understand that the drama with various aspects of political-economics and psychology in a certain popular cultural contents. People, however, does want to reconstruct the meaning of the real world and the hyper - reality, it means cross of oldness and newness, through the films. We try to analyze in religious/philosophical aspect with hybrid narrative, characters and condensed meaning in series. This try shows a good example way of understanding series which on the border line of newness and oldness.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.294-294
• /
• 2014

Developing magnetic thin films with desirable physical properties is a key step to promote research in spintronics. Organic-based magnetic material is a relatively new kind of materials which has magnetic properties in a molecular and microscopic level. These materials have been constructed by the coordination between 3d transition metal and organic materials producing long-range magnetic orders with a relatively high transition temperature. However, these materials were mostly synthesized as a form of powder, which is difficult to study for their physical properties as well as apply for electronic/spintronic devices. In this study, we have employed physical vapor deposition (PVD) to develop a new organic-based hybrid magnetic film that is achieved by the coordination of Fe and tetracyanoquinodimethane (TCNQ). The IR spectra of the grown film show modified CN vibration modes in TCNQ, which suggest a strong bonding between Fe and TCNQ. The thin film has both ferromagnetic and semiconducting behaviors, which is suitable for molecular spintronic applications. The high resolution photoemission (HRPES) spectra also show shift of 1s peak point of nitrogen and the carbon 1s peaks display traces of charge transfer from Fe to TCNQ as well as shake-up features, which suggest strong bonding and anti-bonding nature of coordination between Fe and TCNQ.