• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.190-193
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• 2002

The processing technology of organic thin-film transistors (Ons) performances have improved fur the last decade. Gate insulator layer has generally used inorganic layer, such as silicon oxide which has properties of a low electrical conductivity and a high breakdown field. However, inorganic insulating layers, which are formed at high temperature, may affect other layers termed on a substrate through preceding processes. On the other hand, organic insulating layers, which are formed at low temperature, dose not affect pre-process. Known wet-processing methods for fabricating organic insulating layers include a spin coating, dipping and Langmuir-Blodgett film processes. In this paper, we propose the new dry-processing method of organic gate dielectric film in field-effect transistors. Vapor deposition polymerization (VDP) that is mainly used to the conducting polymers is introduced to form the gate dielectric. This method is appropriate to mass production in various end-user applications, for example, flat panel displays, because it has the advantages of shadow mask patterning and in-situ dry process with flexible low-cost large area displays. Also we fabricated four by four active pixels with all-organic thin-film transistors and phosphorescent organic light emitting devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.185-190
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• 2003

In this paper, it was demonstrated that the organic thin film transistors were fabricated by the organic gate insulators with vapor deposition polymerization (VDP) processing. In order to form polyimide as a gate insulator, vapor deposition polymerization process was also introduced instead of spin-coating process, where polyimide film was co-deposited by high-vacuum thermal evaporation from 4,4'-oxydiphthalic anhydride (ODPA) and 4,4'-oxydianiline (ODA) and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and ODA, and cured at $150^{\circ}C$ for 1hr. Electrical output characteristics in our organic thin film transistors using the staggered-inverted top-contact structure obtained to the saturated slop in the saturation region and the subthreshold non-linearity in the triode region. Field effect mobility, threshold voltage, and on-off current ratio in $0.45\;{\mu}m$ thick gate dielectric layer were about $0.17\;cm^2/Vs$, -7 V, and $10^6\;A/A$, respectively. Details on the explanation of compared to organic thin-film transistors (OTFTS) electrical characteristics of ODPA-ODA and 6FDA-ODA as gate insulators by fabricated thermal co-deposition method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.61-62
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• 2006

In this paper, it was demonstrated that organic thin- film transistors (OTFTs) were fabricated with the organic adhesion layer between an organic semiconductor and a gate insulator by vapor deposition polymerization (VDP) processing. In order to form polymeric film as an adhesion layer, VDP process was also introduced instead of spin-coating process, where polymeric film was co-deposited by high-vacuum thermal evaporation from 6FDA and ODA followed by curing. The saturated slop in the saturation region and the subthreshold nonlinearity in the triode region were c1early observed in the electrical output characteristics in our organic thin film transistors using the staggered-inverted top-contact structure. Field effect mobility, threshold voltage, and on-off current ratio in 15-nm-thick organic adhesion layer were about $0.5\;cm^2/Vs$, -1 V, and $10^6$, respectively. We also demonstrated that threshold voltage depends strongly on the delay time when a gate voltage has been applied to bias stress.

• Korean Journal of Organic Agriculture
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• v.20 no.3
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• pp.297-311
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• 2012

Since 1997, Korean Ministry of Knowledge Economy and Ministry of Environment have established data on some 400 basic raw and subsidiary materials and process like energy, petro-chemical, steel, cement, glass, paper, construction materials, transportation, recycling and disposal etc by initiating establishment of LCI database. Regarding agriculture, Rural Development Administration has conducted establishment of LCI database for major farm products like rice, barley, beans, cabbage and radish etc from 2009, and released that they would establish LCI database for 50 items until 2020 later on. The domestic LCI database for seeds, seedling, agrochemical, inorganic fertilizer and organic fertilizer etc is only at initial stage of establishment, so overseas LCI databases are brought and being used. However, since the domestic and overseas natural environments differ, they fall behind in reliability. Therefore, this study has the purpose to select organic farming materials, survey the production process for various types of organic farming materials and establish LCI database for the effects of greenhouse gas emitted during the process in order to select carbon basic units for agricultural production system compliant in domestic situation instead of relying on overseas data and apply life cycle assessment of greenhouse gas emitted by each crop during the process. As for selecting methods, in this study organic farming materials were selected in the method of direct observation of material and bottom-up method a survey method with focus on the organic farming materials admitted into rice production. For the basic unit of carbon emission amount by the production of 1kg of organic farming material, the software PASS 4.1.1 developed by Korea Accreditation Board under Ministry of Knowledge Economy was used. The study had the goal to ultimately provide basic unit to calculate carbon emission amount in executing many institutions like goal management system and carbon performance display system etc in agricultural sector to be conducted later on. As a result, emission basic units per 1kg of production were calculated to be 0.0088kg-$CO_2$ for charcoal, 0.1319kg-$CO_2$ for grass liquid, and 0.2804kg-$CO_2$ for microbial agent.

• Ecology and Resilient Infrastructure
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• v.9 no.2
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• pp.107-112
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• 2022

This study was conducted to investigate the effects of mulching materials in extensive green roof system by comparing and analyzing the soil moisture content and growth response of Lychnis cognata according to the types of organic mulching materials. The experimental group consisted of a control group that did not use mulching material (Cont.) and a total of five treatment groups, including cocochip (C.O), woodchip (W.O), straw (S.T), and sawdust (S.A), depending on the mulching material. The soil moisture content according to the type of organic mulching material was high in the order of W.O > S.T > Cont. > C.O > S.A, and there was a significant difference especially in S.A. The plant height showed good growth in the order of S.T > Cont. > C.O > W.O > S.A, and there was no significant difference by mulching materials in other growth items except for plant height. Both the chlorophyll and plant water contents were superior to those of untreated group, so the treatment of organic mulching materials is considered to be effective in maintaining the chlorophyll and plant water contents of Lychnis cognata. In particular, the soil moisture content was affected by the characteristics of the mulching material itself. Based on these results, it is required to use a mulching material suitable for the characteristics of each plant in extensive green roof system and it is considered that this can be overcome through organic mulching when selecting a plant species that is weak to water stress.

• Journal of Environmental Science International
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• v.8 no.2
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• pp.221-225
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• 1999

This study was conducted to evaluate the treatment efficiency including reaction kinetics and hydraulic characteristics of food processing wastewater by using an ejector-type aeration system (ETAS) in activated sludge process. The oxygen transfer efficiency in ETAS can be changed in accordance with the depth of reactor. However, the optimum air velocity was found less than 1.82 m/hr at a superficial liquid velocity of 634 m/hr. The ETAS process showed higher organic material removal efficiency than that of the existing activated sludge process under hydraulic detention time 6 to 12 hours. This process, which can maintain MLVSS highly, is able to have high organic material removal efficiency at short HRT and deal with variable organic material loading.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1266-1267
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• 2011

We studied the influence of cathode material on the stability of organic phtovoltaics (OPVs). OPVs with LiF/Al and Ag/Ca/Ag cathode were fabricated and the stability were evaluated. The sample with LiF/Al cathode showed efficiency degradation from 2.42% to 2.04% during 50 days. On the other hand, the sample with Ag/Ca/Ag cathode showed more steeper efficiency degradation from 2.38% to 0.80% during 50 days. The different of degradation can be attributed to a larger increase of series resistance ($R_s$) in Ag/Ca/Ag cathode sample.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.274-275
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• 2006

A new thin film materials can be built up at the molecular level, and the relationship between these artificial structures and the properties of materials can be explored. In this paper, in order to confirm the application possibility to the molecular electronic device of the organic materials, we have investigated electro-luminescent (EL) characteristics of organic EL device using $Alq_3$, PBD as emitting material. Current and luminance can be seen that express a similar relativity in voltage and could know that luminance is expressing current relativity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.132-132
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• 2010

In a previous report, we demonstrated that poly (3,4-ethylenedioxythiophene) derived from poly (ionic liquid) (PEDOT:PIL) constitutes a polymeric hole-injecting material capable of improving device lifetime in organic light-emitting diodes (OLEDs).was attributed to aprotection characteristic of PEDOT:PIL for the indium extraction from ITO electrodes, which frequently occurrs in the OLED device with the conventional PEDOT materials. In this study, we report the OLED device lifetime as well asvice efficiencycan be further improved with the modified PEDOT:PIL in whichorganic compounds are incorporated. The deviced performance will be presented in terms of device lifetime and efficiencies.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1565-1568
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• 1996

The adsorption and desorption behavior of orgnaic gases were investigated using the resonant frequency and admittance method. Sensitive material were depositied on the quartz crystal microbalence by using Langmuir-Blodgett method. To investigate the response characteristics of organic gases, Resonant frequency-Resonant admittance (F-A) diagram was used. The quantity and quality information about organic gases can be obtained by that diagram. As a results, when the organic gases were adsorpted into sensitive material, the physical property changees of sensitive material were occured.