• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.348-348
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• 2016

Low dark current (off-current) and high photo current are both essential for a solution processed organic photodetector (OPD) to achieve high photo-responsivity. Currently, most OPDs utilize a bulk heterojunction (BHJ) photo-active layer that is prepared by the one-step deposition of a polymer:fullerene blend solution. However, the BHJ structure is the main cause of the high dark current in solution processed OPDs. It is revealed that the detectivity and spectral responsivity of the OPD can be improved by utilizing a photo-active layer consisting of an interdiffused polymer/fullerene bilayer (ID-BL). This ID-BL is prepared by the sequential solution deposition (SqD) of poly(3-hexylthiophene) (P3HT) and [6,6] phenyl C61 butyric acid methyl ester (PCBM) solutions. The ID-BL OPD is found to prevent undesirable electron injection from the hole collecting electrode to the ID-BL photo-active layer resulting in a reduced dark current in the ID-BL OPD. Based on dark current and external quantum efficiency (EQE) analysis, the detectivity of the ID-BL OPD is determined to be $7.60{\times}1011$ Jones at 620 nm. This value is 3.4 times higher than that of BHJ OPDs. Furthermore, compared to BHJ OPDs, the ID-BL OPD exhibited a more consistent spectral response in the range of 400 - 660 nm.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.314.1-314.1
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• 2013

Transparent conducting nanoscale-domes were periodically patterned on a Si substrate by nanoimprint method. Transparent conductor of indium-tin-oxide (ITO) was shaped as a nanodome, which effectively drives the incident light effectively into a light-absorber and therefore induces a substantially enhanced photo-response. An ITO nanodome is electrically isolated from the neighboring nanodomes. This structure benefits to provide a low contact between a Si substrate and a front metal electrode giving an efficient electrical path. The ITO nanodome device showed a significantly enhanced photo-response of 6010 from the value of 72.9 of a planar ITO film. The electrical and optical advantage of an ITO nanodome is suitable for various photoelectric applications.

• KIEE International Transactions on Electrophysics and Applications
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• 제11C권4호
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• pp.133-137
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• 2001

In this research, we synthesized various photo-crosslinkable polyimide based polymers. The control of pretilt angles for a nematic liquid crystal (NLC) using the photodimerization method on the photopolymers was studied. A good thermal stability of the photopolymers was measured by thermogravimetric analysis (TGA) measurement until 450C. High pretilt angles of the NLC were otained by polarized UV exposure on the photopolymers containing biphenyl (BP), decyl (de), and cholesteryl (chal) groups, respectively. However, low pretilt angles of the NLC were measured by polarized UV exposure on the photopolymers containing fluorine and chalcone groups. The high NLC pretilt angles generated are attributable to the biphenyl and alkyl moieties, and the photodimerized chalocone group of the photopolymers. Additionally, good voltage-transmittance and response time characteristics were observed by UV exposure on the photopolymers.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.244-244
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• 2006

We developed novel polymer materials composed of thermoresponsive pNIPAAm main chain and photo-resnposive side chains of spirobenzopyran, and analyzed the photoresponsive characteristrics of the aqueous solutions of these copolymers. Further, we prepared various photoresponsive hydrogels composed of the copolymer, and investigated the effect of light irradiation on their properties. As a result, the copolymer exhibited quite unique response to light irradiation and the change in temperature and pH. Especially the drastic photo-induced dehydration was observed in low pH conditions, and photo-induced micro-relief formation was demonstrated using the hydrogel layer composed of the polymer.

• 한국전자통신학회논문지
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• 제7권3호
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• pp.579-583
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• 2012

환경적으로 발생하는 미세입자를 감지하는 시스템을 설계하고 제작하였다. 미세입자 감지시스템은 광산란 현상을 이용하였으며, 레이저다이오우드, 렌즈, aperture, 수광소자로 구성되어진다. 검출시스템의 성능을 좋게 하기 위해 aperture, 렌즈, 수광소자의 위치를 시뮬레이션을 통해 최적화하였다. 제작된 감지시스템으로 유입되는 미세입자에 의한 광산란을 감지하므로 빠른 응답특성를 가지는 미세입자 감지시스템을 제작하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.109-112
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• 1998

In this paper, we studied on electro-optical (EO) characteristics of photo-aligned twisted nematic (TN)-LCD. We obtained that uniform LC alignment in TN-LCD with linearly polarized ultraviolet (LPUV) light irradiation on polyimide (PI) surface increases according to increasing irradiation time for 10 to 60 min. The voltage-transmittance and response time characteristics of photo-aligned TN-LCD with UV light irradiation time of 60 min were almost same in comparison with conventional TN-LCD were observed. From the results, we suggest that photo-aligned TN-LCD with LPUV light irradiation on PI surface is useful in applying LCD as for rubbing-free treatment method.

• E2M - 전기 전자와 첨단 소재
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• 제10권6호
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• pp.576-580
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• 1997

In this paper, the viewing angle characteristics of amorphous (a) - twisted nematic (TN)-liquid crystal display (LCD) on poly(vinyl)cinnamate (PVC) surface with UV (ultraviolet) light irradiation were investigated. It was found that the threshold voltage increases with increasing the polymerization of PVC surfaces. We observed that the domain size of a-TN-LCD decreases with increasing the photo polymerization by increasing UV light irradiation time on PVC films. Also, we observed that the viewing angle of a-TN-LCD increased with increasing the photo polymerization on PVC surfaces. Finally, we consider that the viewing angle of a-TN-LCD on PVC surfaces is large compared to a-TN-LCD on polyimide (PI) surface.

• Corrosion Science and Technology
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• 제2권1호
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• pp.7-11
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• 2003

Photoelectrochemical response and electrochemical impedance behavior was investigated for passive film formed on sputter-deposited Cr alloy in $0.1kmol{\cdot}m^{-3}$. Photoelectrochemical action spectrum could be separated into two components, which were considered to be derived from $Cr_2O_3$ ($E_g\sim3.6eV$) and $ Cr(OH)_3 $ ($E_g\sim2.5eV$). The band gap energy, $E_g$, of each component was almost constant for various applied potentials. polarization periods and alloying additives. The photoelectrochemical response showed negative photo current for most potentials in the passive region. Therefore, the photo current apparently exhibited p-typesemiconductor behavior. On the other hand, Mort-Schottky plot of the capacitance showed positive slope, which means that passive film formed on Cr alloy has n-type semiconductor property. These apparently conflicting results are rationally explained assuming that the passive film on Cr alloy formed in the acid solution has n-type semiconductor property with a fairly deep donor level in the band gap and forms an accumulation layer in the most of potential region in the passive state.

• 한국작물학회지
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• 제22권2호
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• pp.71-79
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• 1977

대맥품종들의 일장에 따른 출수반응과 출수기에 대한 유전을 구명코져 1974연부터 1975연까지 조숙품종으로 올보리, Haganemugi, CI 6332, 중숙품종으로 수원 18호, 부여, 만숙품종으로 수원004, 수원 16005, Samheung을 상호교배하여 만든 Diallelcross F$_1$을 호남작물시험장온실에 파종, 24시간, 16시간 12시간 및 8시간 일장을 각각 처리실험하였던바 그 결과를 요약하면 다음과 같다. 1. Haganemugi, CI 6332는 출수기에 관여하는 순수조만성이 짧은 품종이었고 수원004는 순수조만성이 긴 품종이었다. 2. 품종의 출수기 변이폭은 12시간 일장에서 가장 컸으며 Haganemugi는 다른 품종에 비하여 일장반응이 둔감하였다. 3. 대맥의 순수조만성은 부분우성인 대립유전자에 지배되고 조숙이 우성(CI6332), 또는 열성(Haganemugi)으로 작용하였다. 4. 일장반응에 대한 db전은 비감광성이 감광성에 대하여 단순열성으로 나타났고, Haganemugi가 비감광성유전자를 가지고 있으며 이 유전자는 12시간 일장근처에서 다른 품종의 일장감응성과 구별되었다. 5. 대맥품종에 있어서 일장감응성은 각 품종별로 특별한 Turning point가 있는 것으로 추측되었다.

• 한국작물학회지
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• 제64권3호
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• pp.213-224
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• 2019

There is an increasing frequency in the occurrence of abnormal weather phenomena such as sharp increases and decreases in temperature. Under these weather conditions, the heading time of rice changes unexpectedly, which poses problems in agriculture. Therefore, we investigated the effect of temperature on the heading response at different growth stages in rice. During the period from transplanting to heading, the plants were subjected to different temperature treatments, each for a 9-day period, to observe the heading response. For the heading date analysis, "heading date" was defined as the number of days from transplanting to the appearance of the first spikelet. We found that the influence of temperature increased in the order of rooting stage, followed by meiosis, early tillering, spikelet differentiation, and panicle initiation stage in all ecological types and cultivars. In particular, unlike the results reported previously, the effect of temperature on heading during the photo-sensitive period was very small. Meanwhile, the influence of temperature on vegetative growth response at different growth stages was not consistent with heading response. These results can be used as basic data for predicting the variation in heading date owing to temperature variation at each growth stage. In addition, we propose that the concept of day length should be included in determining the influence of temperature on the photo-sensitive period.