• Title, Summary, Keyword: luminescence

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Numerical Analysis of OLED Luminescence Efficiency by Hole Transport Layer Change (유기발광 소자의 수송층 두께 변화에 따른 수치적 해석)

  • Lee, Jung-Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.12
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    • pp.1341-1346
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    • 2004
  • The OLED research is gone for two directions. One is material development research, and another one is structural improvement part. All two are thing to heighten luminescence efficiency of OLED. n other to improve luminescence efficiency of OLED Electron - hole pairs must consist much more in the device Their profiles are sensitive to mobility velocity of electrons and holes. In this paper, we demonstrate the difference of velocity between hole and electron by experiments, and compare with a data of simulation and experiment changing hole carrier transport layer thickness, so we get the optimal we improve luminescence efficiency. We suggest improving the efficiency of OLEDS would be to balance the injection of electrons and holes into light emission layer of the device. And, we improve understanding of the various luminescence efficiency through experiments and numerical analysis of luminescence efficiency in variable hole carrier transport layer's thickness.

The study of Luminescence Efficiency of OLED (유기발광 소자의 발광효율 연구)

  • Lee, Jung-Ho
    • Proceedings of the Optical Society of Korea Conference
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    • pp.172-173
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    • 2004
  • Recently there has been many understood the basis device physics OLEDs and their basic operating principle. We demonstrate that there have many relation in order to improve luminescence efficiency both emitting light material physics characteristics and luminary. Efficient Electro Luminescence from organic materials was first reported in 1987 at Kodak. OLEDs emitting light material use tris-(8-hydroxyquinoline)(Alq3). Sudied maximum luminescence efficiency about structure of optimized emitting light layer of OLED which do observing change of luminescence efficiency by structure change of organic material in this paper.

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EFFECT OF PHOTOCHEMICAL REACTIONS ON LUMINESCENCE OF CRYSTALLINE RDX

  • Kim, Hack-Jin;Kang, Tai-Jong
    • Journal of Photoscience
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    • v.2 no.2
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    • pp.83-87
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    • 1995
  • Luminscence spectra and decay of crystalline hexahydro-1,3,5-trinitro-1,3,5-s-tetrazine (RDX) are observed at 90 K and the effects of photochemical reaction on the luminescence of RDX are investigated. The uv light from high power Hg lamp is used for the photochemical reaction of RDX. While no significant changes are observed in the luminescence spectra after the photochemical reaction, the intensity profile of the spectra changes with the progress of chemical reactions. The biexponential decay of luminescence is modified by chemical reactions. Features of the electronic states of crystalline RDX are discussed in relation to the luminescence.

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The Interaction Expressed in 21st Century's Digital Fashion - Focused on the Luminescence digital fashion designs - (21세기 디지털 패션에 나타난 인터랙션 - 발광형 디지털 패션디자인을 중심으로 -)

  • Heo, Seungyeun;Lee, Younhee
    • Journal of the Korean Society of Costume
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    • v.63 no.4
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    • pp.17-29
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    • 2013
  • The purpose of this study is to analyze the factors of action and reaction through the examples of luminescence digital fashion design, which is a part of the interactive digital paradigm in 21st century, and to classify types of interaction expressed in luminescence digital fashion design. The significance of this study is to provide an effective database for researches on new ideas and expression methods of fashion design using luminescence digital device. The contents are as follows. First, identifying the concepts of interaction, digital fashion, and luminescence digital device. Second, analyzing the factors that put the luminescence digital device into effect through materials such as the collected photos and the stimulus behind the materials. Third, analyzing and classifying types of reaction according to the types of stimulus in luminescence digital fashion design. Detailed use of luminescence digital devices in Fashion designs did not start until after 2000 so the scope of this study starts from 2000 and on. The methods of this study are as follows. The theoretical frameworks of digital fashion and interaction were setup by using information from various related books, papers, and internet sites. In addition, the empirical analysis was performed using collected photos and explanations through related Internet sites of digital fashion. Through the study, the interaction types in 21st century's luminescence digital fashion design can be expressed variously according to the current input type, biometric recognition type, environment recognition type.

Synthesis and Luminescence Properties of CaS:Eu2+,Si4+,Ga3+ for a White LED

  • Oh, Sung-Il;Jeong, Yong-Kwang;Kang, Jun-Gill
    • Bulletin of the Korean Chemical Society
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    • v.30 no.2
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    • pp.419-422
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    • 2009
  • The luminescence intensity of calcium sulfide codoped with $Eu^{2+},\;Si^{4+}\;and\;Ga^{3+}$ was investigated as a function of the dopant concentration. An enhancement of the red luminescence resulted from the incorporation of $Si^{4+}\;and\;Ga^{3+}\;into\;CaS:Eu^{2+}.\;The\;non-codoped\;CaS:Eu^{2+}$ converted only 3.0% of the absorbed blue light into luminescence. As the $Si^{4+}\;and\;Ga^{3+}$ were embedded into the host lattice, the luminescence intensity increased and reached a maximum of Q = 10.0% at optimized concentrations of the codopants in CaS. Optimized CaS:$Eu^{2+},Si^{4+},Ga^{3+}$ phosphors were fabricated with blue GaN LED and the chromaticity index of the phosphor-formulated GaN LED was investigated as a function of the wt% of the optimized phosphor.

The Study of Photo-Luminescence on Willemite Phosphor (Willemite 형광체의 Photo-Luminescence 특성에 관한 연구)

  • 장창섭;오근호;이종근
    • Journal of the Korean Ceramic Society
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    • v.21 no.3
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    • pp.245-252
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    • 1984
  • Willemite phosphor is a good one having excellent luminescence efficiency that it;s emission wavelength is in the range of about 525 nm. The energy band gap of this willemite phosphor is about 4.1 eV. When the ratio of ZnO/SiO is 1.8 and Mncl in used as activator source the phosphor has the value of maximum luminescence efficiency. The characteristic of willemite phosphor is tendency of the dependence of temperature. The willemite which was fired with activator after being synthesized at initial firing without activator shows higher value of luminescence efficiency than willemite which was fired with activator in initial stage, When the concentration of activator is 1-1.5mol% it has its most favorite condition and the value of luminescence efficiency decreases according to increasement of activator concentration.

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An Integrated System for Radioluminescence, Thermoluminescence and Optically Stimulated Luminescence Measurements

  • Park, Chang-Young;Park, Young-Kook;Chung, Ki-Soo;Lee, Jong-Duk;Lee, Jungil;Kim, Jang-Lyul
    • Journal of Radiation Protection and Research
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    • v.43 no.4
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    • pp.160-169
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    • 2018
  • Background: This study aims to develop an integrated optical system that can simultaneously or selectively measure the signals obtained from radioluminescence (RL), thermoluminescence (TL), and optically stimulated luminescence (OSL), which are luminescence phenomena of materials stimulated by radioactivity, heat, and light, respectively. The luminescence mechanism of various materials could be investigated using the glow curves of the luminescence materials. Materials and Methods: RL/TL/OSL integrated measuring system was equipped with a X-ray tube (50 kV, $200{\mu}A$) as an ionizing radiation source to irradiate the sample. The sample substrate was used as a heating source and was also designed to optically stimulate the sample material using various light sources, such as high luminous blue light emitting diode (LED) or laser. The system measured the luminescence intensity versus the amount of irradiation/stimulation on the sample for the purpose of measuring RL, TL and OSL sequentially or by selectively combining them. Optical filters were combined to minimize the interference of the stimulation light in the OSL signal. A long-pass filter (420 nm) was used for 470 nm LED, an ultraviolet-pass filter (260-390 nm) was used for detecting the luminescence of the sample by PM tube. Results and Discussion: The reliability of the system was evaluated using the RL/OSL characteristics of $Al_2O_3:C$ and the RL/TL characteristics of LiF:Mg,Cu,Si, which were used as dosimetry materials. The RL/OSL characteristics of $Al_2O_3:C$ showed relatively linear dose-response characteristics. The glow curve of LiF:Mg,Cu,Si also showed typical RL/OSL characteristics. Conclusion: The reliability of the proposed system was verified by sequentially measuring the RL characteristics of radiation as well as the TL and OSL characteristics by concurrent thermal and optical stimulations. In this study, we developed an integrated measurement system that measures the glow curves of RL/TL/OSL using universal USB-DAQs and the control program.

고출력 LED용 형광체 재료 개발

  • Kim, Seon-Uk;Hwang, Jong-Hui
    • Ceramist
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    • v.21 no.1
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    • pp.80-97
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    • 2018
  • To realize a high luminous efficacy and a high emission color purity for the white-LEDs, the understanding for luminescence properties of the phosphors is significantly important because the performance of white-LEDs is directly affected by the luminescence properties of the phosphors. In this paper, therefore, we reviewed some commercially available $Eu^{2+}$- and $Ce^{3+}$- activated phosphors and discussed for the luminescence properties of these phosphors.

A New Analytical Method for the $Dy^{3+}$ Ion Using the Luminescence Enhancement by the Treatment of o-Phenanthroline on the TLC Plate (TLC Plate에서의 발광증폭 및 o-Phenanthroline에 의한 Energy Transfer를 이용한 $Dy^{3+}$ 이온의 미량 분석법)

  • Jeong, Hyuk
    • Analytical Science and Technology
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    • v.11 no.5
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    • pp.386-393
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    • 1998
  • A new analytical luminescence method for the $Dy^{3+}$ ion was studied using the luminescence enhancement by the treatment of the o-phenanthroline on the TLC plate. Compared to the specific emission intensities of the ion in water solution, if the ion solution is spotted on the TLC plate, the luminescence intensities were extremely enhanced. There was additional enhancement effect of the luminescence intensities of the ions on the TLC plate, if the ion on the TLC plate is treated with o-phenanthroline. Based on the luminescence enhancement, the detection limit was improved by more than 4 order of magnitude compared to that of solution sample. The dynamic ranges and correlation coefficients of the calibration curves near the detection limit were 102 order and ~0.99, respectively. The energy-transfer mechanism was explained for the theoretical back ground of the luminescence enhancement.

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