• Title/Summary/Keyword: Green emission

검색결과 1,029건 처리시간 0.029초

Improvement In recombination at a two-emission-layers interface For White-light-emitting organic electroluminescent device

  • Song, Tae-Joon;Ko, Myung-Soo;Lee, Gyu-Chul;Cho, Sung-Min
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.928-931
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    • 2003
  • In order to realize full color display, two approaches were used. The first method is the patterning of red, green, and blue emitters using a selective deposition. Another approach is based on a white-emitting diode, from which the three primary colors could be obtained by micro-patterned color filters. White-light-emitting organic light emitting devices (OLEDs) are attracting much attention recently due to potential applications such as backlights in liquid crystal displays (LCDs) or other illumination purposes. In order for the white OLEDs to be used as backlights in LCDs, the light emission should be bright and have Commission Internationale d'Eclairage (CIE) chromaticity coordinates of (0.33, 0.33). For obtaining white emission from OLEDs, different colours should be mixed with proper balances even though there are a few different methods for mixing colors. In this study, we will report a white organic electroluminescent device using exciton diffusion length concept.

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고온 공기와 선회수에 의한 동축 분류 화염의 연소 특성 (Combustion characteristics of coaxial diffusion flame with high preheated and swirled air)

  • 김진식;곽지현;전충환;장영준
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 추계학술대회논문집B
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    • pp.112-117
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    • 2001
  • An experiment using high preheated and swirled air in the coaxial diffusion flame burner was carried out in order to decrease NOx emission and improve the thermal efficiency. $N_2$ gas was used for diluent and propane was utilized for fuel. Combustion using high preheated air has two remarkable characteristics ; (1) low NOx emission with increasing dilution level, (2) high thermal efficiency in the furnace. Also, swirled air can mix fuel and oxidizer well in condition of diffusion flme and maintain the stable combustion. The color of flame changes from yellow to blue green according to increasing the dilution level of mixture gas. NO emission decreased with increasing dilution level and the swirl number.

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희토류계 Erbium을 도핑한 ZnO 형광체의 발광특성 (Luminescent Properties of Er-Doped ZnO Phosphors)

  • 송현돈;김영진
    • 한국재료학회지
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    • 제16권1호
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    • pp.58-62
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    • 2006
  • Effects of doping concentration and annealing atmosphere on the luminescent properties of $Er^{3+}$ doped ZnO phosphor powders were investigated. Photoluminescence (PL) spectra of ZnO:Er exhibit an orange emission band at around 575 nm, while those of pure ZnO show a green emission at 520 nm. Emission difference between ZnO:Er and pure ZnO is attributed to the energy transfer of Er ions in ZnO. The highest PL intensity is obtained by doping 1 mol% Er to ZnO. Luminescent properties of ZnO:Er phosphors annealed at $N_2$+vacuum atmosphere are superior to those annealed at $N_2$ atmosphere.

PLD로 증착한 ZnO 박막의 발광 특성 분석 (Emission Properties of ZnO Grown by PLD)

  • 배상혁;이상렬
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2000년도 추계학술대회 논문집 학회본부 C
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    • pp.422-424
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    • 2000
  • ZnO thin films for light emission device have been deposited on sapphire and silicon substrates by pulsed laser deposition technique(PLD). A Nd:YAG laser was used with the wavelength of 355 nm. In order to investigate the emission properties of ZnO thin films, PL measurements with an Ar ion laser as a light source using an excitation wavelength of 351 nm and a power of 100 mW are used. All spectra were taken at room temperature by using a grating spectrometer and a photomultiplier detector. ZnO exhibited PL bands centered around 390, 510 and 640 nm, labeled near ultra-violet (UV), green and orange bands. Structural properties of ZnO thin films are analized with X-ray diffraction (XRD).

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펄스 레이저 증착법으로 제작한 ZnO 박막의 발광 특성 (Light emission properties of ZnO thin films grown by pulsed laser deposition)

  • 배상혁;이상렬
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 추계학술대회 논문집
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    • pp.539-542
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    • 2000
  • ZnO thin films for light emission device have been deposited on sapphire and silicon substrates by pulsed laser deposition technique(PLD). A Nd:YAG laser was used with the wavelength of 355 nm. In order to investigate the emission properties of ZnO thin films, PL measurements with an Ar ion laser as a light source using an excitation wavelength of 351 nm and a power of 100 mW are used. All spectra were taken at room temperature by using a grating spectrometer and a photomultiplier detector. ZnO exhibited PL bands centered around 390, 510 and 640 nm, labeled near ultra-violet (UV), green and orange bands. Structural properties of ZnO thin films are analized with X-ray diffraction (XRD).

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잎 표면의 분무입자 부착특성에 따른 제초제 침투성 분석 (The Analysis of Herbicide Penetration with Spray Deposit Characteristics on Plant Leaves)

  • 장영창
    • Journal of Biosystems Engineering
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    • 제25권4호
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    • pp.287-292
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    • 2000
  • The herbicide penetration on weed leaves was spatially analyzed by using chlorophyll fluorescent emission and machine vision technique. Velvetleaf and metribuzin were used as experimental materials in the study. The herbicide spray images were obtained by a combinaton of a fluorescent dye and a UV lighting system. The herbicide penetration was analyzed by means of detecting chlorophyll fluorescent emission under blue-green lighting. According to the experiment results, the number and the size of spray droplets decreased with coverage increasing. The herbicide penetrated mainly along leaf veins and the time for complete penetration over the whole leaf was approximately 100 minutes after herbicide spraying. When the coverage of herbicide droplets on the surface of leaves increased, the speed of herbicide penetration also increased. This study suggested a way of characerizing herbicide spatial penetration and distribution in leaves.

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Preparation and Photoluminescence Properties of the ZnGa₂O₄: Mn Phosphor by Polymerized Complex Precursor

  • 조두환;정하균;석상일;박도순
    • Bulletin of the Korean Chemical Society
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    • 제18권6호
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    • pp.608-612
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    • 1997
  • The preparation and photoluminescence properties of $ZnGa_2O_4$ : Mn phosphor are presented. Under 254 nm excitation $Zn_1-_xMn_xGa_2O_4$ exhibits the green emission band at 506 nm wavelength and maximum intensity where x=0.005. The manganese activated $ZnGa_2O_4$ phosphor prepared by the polymerized complex method shows a remarkable increase in the emission intensity and is smaller particle size than that prepared by conventional method. Also, electron paramagnetic resonance study on $ZnGa_2O_4$ : Mn powders indicates that the increase in emission intensity after firing treatment in mild hydrogen reducing atmosphere is due to the conversion of the higher valent manganese to $Mn^{2+}$.

Synthesis of PPV-PTV Alternating Copolymer and EL Devices Using the Polymer

  • 황도훈;정상돈;도래미;안택;심홍구;정태형
    • Bulletin of the Korean Chemical Society
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    • 제19권3호
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    • pp.332-335
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    • 1998
  • An alternating copolymer of PPV and PTV, poly[2-methoxy-5-(3,7-dimethyl)octyloxy-1,4-phenylenevinylene-alt-2,5-thienylenevinylene] (DAPPV-PTV) has been synthesized and light-emitting properties of the polymer have been studied. A single layer EL device using DAPPV-PTV as an emitting layer between ITO and Al electrodes (ITO/DAPPV-PTV/Al) has been fabricated, and light emission of the device becomes visible at 3 V. The EL emission maximum of the device is about 620 nm. Double layer EL device using DAPPV-PTV and Alq3 (ITO/DAPPV-PTV/Alq3/Al) has also been fabricated. The double layer EL device shows two-color emission depending on the applied voltage. The device emits a pale green color from 8 V, and then the color turns to red at about 18 V.

Improvement Directions for the G-SEED System from the Resident's Perspective - Focused on Certification Assessment Criteria for Apartment Buildings -

  • Choi, Yeo Jin;Lhee, Sang Choon
    • KIEAE Journal
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    • 제14권4호
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    • pp.19-26
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    • 2014
  • The building section is providing immediate causes for global climate change problems since it takes about 50% of carbon emission, 20~50% of waste discharge, 33% of energy consumption, 40% of resource use, and 17% of water consumption. So, many countries over the world have developed and implemented green building certification systems to assess sustainable performances of buildings since the early 1990s. In korea, the green building certification system to induce the diffusion of sustainable buildings was first introduced in 2002 and developed as an improved version of the G-SEED(Green Standard for Energy and Environmental Design) system in 2013 after major revisions of related legislations. This research conducts a survey targeting residents on an apartment building that was certified as green building and examines the importance of assessment criteria on apartment buildings to certify green buildings using the Analytic Hierarchy Process(AHP) method. And it proposes a new direction on certification assessment standards from the resident's prospective. As a result, assessment criteria such as indoor environment, ecological environment, energy & environment pollution, and maintenance management among 7 main ones turned out important on assessing the G-SEED system for apartment buildings, while criteria such as material & resource, water circulation management, and land use & transportation did relatively unimportant.

LCA개념을 도입한 학교시설 녹색건축인증기준 개선방향에 관한 연구 (A Study on the Improvement of the School Green Building Certification System based on Life Cycle Assessment Methodology)

  • 이재옥;김성중;이상민;이승민
    • 교육시설 논문지
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    • 제20권3호
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    • pp.53-61
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    • 2013
  • The purpose of this study is to suggest the way how to improve the school green building certification system based on life cycle assessment methodology and to assess $LCCO_2$ in outline. Green Building Certification System for School is comprised of 7 categories and 39 items. 7 categories include Land use and Transport, Energy and Atmosphere, Materials and Resources, Water, Management, Ecology, Indoor environmental quality. School is a public facility for students. So Green Building Certification System for School must have educational point of view adding to energy saving, reduction of greenhouse gas emission, etc. Also it needs to be classified into three categories ; kindergarten, elementar/middl/high school and university. Improvement plans for items are as follows ; energy consumption and $LCCO_2$ assessment considering life cycle, deletion or integration of duplicate items by comparing other systems, application of passive solar systems, consideration of the law and standards change, and selection of items considering specific building use.