• 제목/요약/키워드: High work function

검색결과 692건 처리시간 0.029초

Thickness Effect of ZnO Electron Transport Layers in Inverted Organic Solar Cells

  • Jang, Woong-Joo;Cho, Hyung-Koun
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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    • pp.377-377
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    • 2011
  • Organic solar cells (OSCs) with low cost have been studied to apply on flexible substrate by solution process in low temperature [1]. In previous researches, conventional organic solar cell was composed of metal oxide anode, buffer layer such as PEDOT:PSS, photoactive layer, and metal cathode with low work function. In this structure, indium tin oxide (ITO) and Al was generally used as metal oxide anode and metal cathode, respectively. However, they showed poor reliability, because PEDOT:PSS was sensitive to moisture and air, and the low work function metal cathode was easily oxidized to air, resulting in decreased efficiency in half per day [2]. Inverted organic solar cells (IOSCs) using high work function metal and buffer layer replacing the PEDOT:PSS have focused as a solution in conventional organic solar cell. On the contrary to conventional OSCs, ZnO and TiO2 are required to be used as a buffer layer, since the ITO in IOSC is used as cathode to collect electrons and block holes. The ZnO is expected to be excellent electron transport layer (ETL), because the ZnO has the advantages of high electron mobility, stability in air, easy fabrication at room temperature, and UV absorption. In this study, the IOSCs based on poly [N-900-hepta-decanyl-2,7-carbazole-alt-5,5-(40,70-di-2-thienyl-20,10,30-benzothiadiazole)] (PCDTBT) : [6,6]-phenyl C71 butyric acid methyl ester (PC70BM) were fabricated with the ZnO electron-transport layer and MoO3 hole-transport layer. Thickness of the ZnO for electron-transport layer was controlled by rotation speed in spin-coating. The PCDTBT and PC70BM were mixed with a ratio of 1:2 as an active layer. As a result, the highest efficiency of 2.53% was achieved.

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Fabrication of Micro-inductor and Capacior For RF MEMS Applications

  • Cho, Bek-Hee;Lee, Jae-Ho;Bae, Young-Ho;Cho, Chan-Sub;Lee, Jong-Hyun
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제2권2호
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    • pp.102-110
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    • 2002
  • In this paper, we present the fabrication of tunable capacitors and 3-dimensional inductors. This work was related to fabricated 3-dimensional device for need of micro device in developing new intelligence age. This device was fabricated by electroplating used electroplating PR and high-vacuum evaporation of metal. Fabricated micro-inductor is consisted of air-bridge on electroplating rod and electroplated core. Micro-capacitor is consisted of thin metal membrane and electroplated core. Electroplating material is used Cu metal solvent. Air-gap between metal-layers function as almost perfect isolation layer. The most advantage of our micro-inductor and micro-capacitor compared to present device is a possibility that can fabricate on RF MEMS(microelectro-mechanical systems) application with high performance and various function. In this paper, we present the fabrication of tunable capacitors and 3-dimensional inductors. This work was related to fabricated 3-dimensional device for need of micro-device in developing new intelligence age. This device was fabricated by electroplating used electroplating PR and high-vacuum evaporation of metal. Fabricated micro-inductor is consisted of air-bridge on electroplating rod and electroplated core. Micro-capacitor is consisted of thin metal membrane and electroplated core. Electroplating material is used Cu metal solvent. Air-gap between metal-layers function as almost perfect isolation layer. The most advantage of our micro-inductor and micro-capacitor compared to present device is a possibility that can fabricate on RF MEMS application with high performance and various functions.

고 농도 분진 만성노출 근로자의 세포성 면역기능과 활성산소종 (Reactive Oxygen Species and Cellular Immune Function of Workers Chronically Exposed to High-Level Dusts)

  • 김갑배;김기웅
    • 한국산업보건학회지
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    • 제26권3호
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    • pp.286-292
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    • 2016
  • Objectives: This study aimed to evaluate the effects of chronical exposure to high-level dusts on cellular immune function. Methods: The subjects were 110 male workers, among whom 60 were chronically exposed to high-level dusts in mica, limestone and iron mines. The remaining 50 were office workers. Ambient total, respirable dust and crystalline silica in the workplace were sampled using personal air samplers and analyzed according to NIOSH method 0500. Serum levels of hydrogen peroxide, lipid peroxide and superoxide misutase activity were measured using absorption chromatography. The subpopulations of CD4+, CD8+, natural killer cells (CD16+) and CD3+ T-lymphocytes were examined by two-color staining using monoclonal antibodies. Results: The concentration of hydrogen peroxide was significantly higher in exposed workers and superoxide dismutase activity was significantly higher in control workers. No significant difference in numbers of T-lymphocyte subpopulations were observed between exposed and control workers. A significant correlation in exposed workers was observed among total dusts, respirable dusts and crystalline silica. Hydrogen peroxide was significantly correlated with total dust (r=0.720, p<0.01), respirable dust (r=0.770, p<0.01) and crystalline silica (r=0.678, p<0.01). Concentration of hydrogen peroxide showed a significantly negative correlation with numbers of CD8+ cells (r=-0.274, p<0.01), CD3+ cells (r=-0.222, p<0.01) and natural killer cells (r=-0.556, p<0.01). Conclusions: These results suggest that chronical exposure to high-level dust affects cellular immune function and effects might mediate through reactive oxygen species and inflammatory response.

작업만족과 Ergonomics에 관한 개념적 고찰 (A Conceptional Review of Work Satisfaction & Ergonomics)

  • 김원
    • 산업경영시스템학회지
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    • 제6권8호
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    • pp.13-19
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    • 1983
  • In this paper an attempt is tried to answer the following questions : What does ergonomics have to do with work satisfaction\ulcorner Is there more satisfaction when ergonomics have applied in the design of work\ulcorner Is ergonomics important for work satisfaction\ulcorner This paper is started by defining the concept of satisfaction and ergonomics which is still at a comparatively early stage of development, and the effect of this in practice is that the majority of ergonomics assignments involve research. And then there discussions difficult theories of motivation and satisfaction such as Maslow' theory and Horzberg's theory. And in this paper I'll try to formulate the logical consequences of those theories for the relation between ergonomics and satisfaction. Finally I'll conclude with some ideas about the significance of ergonomics satisfaction. The level of satisfaction experienced with one's work is a complete function of the degree to which different values connected with work and with its concomitant results are attained, the opportunities perceived for the attainment of these values, the relative advantages and disadvantages of the work situation compared with that of other people, and personality and cultural determinants. As for ergonomics, the ergonomist's comprehension will need in future to encompass more of the emotional, attitudinal and motivational facts of working people. Ergonomically - designed work will not produce high degrees of satisfaction, but absence of ergonomics in design will be connected with some dissatisfaction. So this paper suggest s that ergonomics has some significance for work satisfaction and that social Psychological efforts to enhance work satisfaction cannot easily succeed without taking into account human-factors principles.

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Barionic Acoustic Oscillations with 3-point Correlation Function of Quasars

  • Choi, Doohyun;Rossi, Graziano;Slepian, Zachary;Eisenstein, Daniel
    • 천문학회보
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    • 제42권2호
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    • pp.54.2-54.2
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    • 2017
  • While quasars are sparse in number density, they reside at relatively high-redshift as compared to e.g. luminous red galaxies. Hence, they are likely to be less non-linearly evolved than the galaxy population, and thus have a distribution that more closely mirrors the primordial density field. Therefore, they offer an intriguing opportunity to search for Baryonic Acoustic Oscillations (BAO). To this end, the 3-point correlation function (3PCF) is an excellent statistical tool to detect BAO. In this work, we will make the first-ever measurement of the large-scale quasar 3PCF from the SDSS-IV DR14 quasar sample (spanning the largest volume to-date). This work will use the order N2-time 3PCF algorithmof Slepian & Eisenstein (2015), with N the number of objects.

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Constraining primordial non-Gaussianity with the 3-point correlation function of the SDSS-IV eBOSS DR14 quasar sample

  • Choi, Peter D.;Rossi, Graziano;Slepian, Zachary;Eisenstein, Daniel;Ho, Shirley;Schlegel, David
    • 천문학회보
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    • 제42권1호
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    • pp.53.3-53.3
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    • 2017
  • While quasars are sparse in number density, they reside at relatively high-redshift as compared to galaxies. Hence, they are likely to be less non-linearly evolved than the galaxy population, and thus have a distribution that more closely mirrors the primordial density field. Therefore, they offer an intriguing opportunity to search for primordial non-Gaussianity (PNG). To this end, the 3-point correlation function (3PCF) is an excellent statistical tool to detect departures from Gaussianity, vanishing for a Gaussian field. In this work, we will make the first-ever measurement of the large-scale quasar 3PCF from the SDSS-IV DR14 quasar sample (spanning the largest volume to-date) to place constraints on PNG through the usual f_NL-type parametrization. This work will use the order N^2-time 3PCF algorithm of Slepian & Eisenstein (2015), with N the number of objects.

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Theory of Charged Clusters Linking Nano Science and Technology to Thin Films

  • Hwang, Nong-Moon
    • 한국결정학회:학술대회논문집
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    • 한국결정학회 2002년도 정기총회 및 추계학술연구발표회
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    • pp.20-20
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    • 2002
  • Based on experimental and theoretical analyses, we suggested a new possibility that the CVD diamond films grow not by the atomic unit but by the charged clusters containing a few hundreds of carbon atoms, which form spontaneously in the gas phase [J. Crysta] Growth 62 (1996) 55]. These hypothetical negatively-charged clusters were experimentally confirmed under a typical hot-filament diamond CVD process. Thin film growth by charged clusters or gas phase colloids of a few nanometers was also confirmed in Si and ZrO₂ CVD and appears to be general in many other CVD processes. Many puzzling phenomena in the CVD process such as selective deposition and nanowire growth could be explained by the deposition behavior of charged clusters. Charged clusters were shown to generate and contribute at least partially to the film deposition by thermal evaporation. Origin of charging at the relatively low temperature was explained by the surface ionization described by Saha-Langmuir equation. The hot surface with a high work function favors positive charging of clusters while that of a low work function favors negative charging.

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Iodine Doping of Pentacene and its Electrical Properties

  • Rahim, Abdur;Lee, Young-Kyu;Lee, Chi-Young;Lee, Jae-Gab
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2011년도 춘계학술발표대회
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    • pp.238.2-238.2
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    • 2011
  • Organic thin film transistors (OTFTs) have been attracting considerable attention because of their potential use in low-cost, large area, electronic devices such as flexible displays, biochemical sensors, and smart cards. In past several years, gold/pentacene has been frequently used in OTFTs because of the high mobility of pentacene and the high work function of gold. To improve the performance of the OTFTs contact area doping of pentacene with p-doping materials are well known. In this work we demonstrated selectively contact area doping of pentacene with Iodine vapor. For effective doping elevated pentacene layer under the source-drain area was deposited and exposed to Iodine vapor. We got better electrical performance for elevated pentacene structure rather than planer structure with relatively high field-effect mobility.

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High Performance OLEDs with a New Device Structure

  • Noh, Jeoung-Kwen;Kang, Min-Soo;Kim, Jong-Seok;Lee, Jung-Hyoung;Ham, Yun-Hye;Kim, Jung-Bum;Son, Seh-Wan
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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    • pp.1011-1013
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    • 2007
  • We report the fabrication of a new inverted OLED devices having potential to be used for both AMOLED and lighting applications.

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점소성 유한요소법에 의한 이차원 절삭의 구성인선 해석 (Built-Up Edge Analysis of Orthogonal Cutting By Visco-Plastic Finite Element Method)

  • 김동식
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 1995년도 추계학술대회 논문집
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    • pp.60-63
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    • 1995
  • The behavior of the work materials in the chip-tool interface in extremely high strain rates and temperatures is more that of viscous liquids than that of normal solid metals. In these circumstances the principles of fluid mechanics can be invoked to describe the metal flow in the neighborhood of the cutting edge. In the present paper an Eulerian finite element model is presented that simulates metal flow in the vicinity of the cutting edge when machining a low carbon steel with carbide cutting tool. The work material is assumed to obey visco-plastic (Bingham solid) constitutive law and Von Mises criterion. Heat generation is included in the model, assuming adiabatic conditions within each element. the mechanical and thermal properties of the work material are accepted to vary with the temperature. The model is based on the virtual work-stream function formulation, emphasis is given on analyzing the formation of the stagnant metal zone ahead of the cutting edge. The model predicts flow field characteristics such as material velocity effective stress and strain-rate distributions as well as built-up layer configuration

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