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White Light Emitting Diodes of Non-fully Conjugated Coil-like Polymer Doped with Derivatized Multi-wall Carbon NanotubesChang, Yi-jyun 28 July 2006 (has links)
Luminescent emission of non-fully conjugated homopolymers was successfully demonstrated as light emitting diodes (LEDs) in this research. Coil-like heterocyclic aromatic poly[2,2-(2,5-dialkyloxyphenylene)-4-4¡¦-hexafluoroisopropanebibenzoxazo- les] (6F-PBO-CnOTpA, with n = 10, 15, and 20) was synthesized, and polymer composites of 6F-PBO-CnOTpA was in-situ synthesized with acidified multi-wall carbon nanotube (MWNT- COOH).
The non-fully conjugated coil-like heterocyclic aromatic homopolymer was synthesized by reacting 2,2,bis-(3-amino-4-hydroxy[henyl]-hexafluoropropane with 2,5-dialkyloxyterephthalic acid (CnOTpA) for 6F-PBO-CnOTpA, with n = 10, 15, and 20. In addition, MWNT was acidified for connecting the carboxylic group (-COOH) to reduce its aspect ratio and entropy induced aggregation. MWNT-COOH was analyzed using elemental analysis (EA) and viscometry to validate the effects of acidification period. The EA result seemed to suggest that the oxygen content increased, and the carbon and the hydrogen contents decreased with acidification period. The inherent viscosity (£binh) decreased according to acidification period suggesting that the aspect ratio was indeed decreased.
A hole transport layer of PEDOT¡GPSS was applied for multi-layer LEDs,. The LEDs all showed a threshold voltage about 4 V also for the composites of 6F-PBO-CnOTpA in-situ polymerized with MWNT-COOH. The 6F-PBO-CnOTpA LEDs with and without MWNT-COOH showed an electroluminescence emission range of 400 to 750 nm.
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Phosphorescent cyclometalated iridium(III) complexes and corresponding conducting metallopolymersHesterberg, Travis Wayne 06 July 2012 (has links)
Conducting metallopolymers have been investigated for a variety of applications
due to their ability to take advantage of both the mechanical processability of the polymer
material, as well as the optical and electronic properties of the metal. Our project goal is
to design, synthesize and characterize novel iridium(III)-containing conducting
metallopolymers for use as the active layer in polymer light-emitting diodes. We have
utilized thiophene functionalized ligands that can be readily electropolymerized into
conducting polymer thin films and can be easily incorporated into a device structure.
Iridium(III) was chosen as the metal center due to its promising photophysical properties,
as similar complexes have demonstrated high luminescent quantum yields and short
phosphorescent lifetimes. The coordination environment around the metal can be altered
synthetically to tune the emission wavelength across the visible spectrum. The synthetic
control over the polymer backbone, as well as the iridium(III) ligand environment,
allowed us to independently vary each component, which has provided a variety of
materials. The materials are characterized through 1H and 13C NMR, mass spectrometry,
elemental analysis, electrochemistry, X-Ray diffraction and X-Ray Photoelectron
Spectroscopy. The photophysical properties of the materials are studied through UVvii
Visible absorption spectroscopy, UV-Vis-NIR spectroelectrochemistry and steadystate/
time-resolved emission spectroscopy. / text
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Desenvolvimento de um sistema eletrônico de acionamento e controle para avaliação de desempenho de mostradores de informações baseados em LEDs poliméricos. / Development of an electronic system of driver and control for perfomance evaluation of displays based on polymer LEDs.Pimentel, Fabio Henrique 09 November 2007 (has links)
Neste trabalho é apresentado o estudo e o desenvolvimento de um sistema eletrônico de teste, para avaliação de desempenho de diodos emissores de luz poliméricos - PLEDs, ou de mostradores de informações com até 35 PLEDs em matriz passiva produzidos em laboratório. Os requisitos de acionamento e controle, baseados nas características estruturais e elétricas de PLEDs e mostradores de PLEDs, foram cuidadosamente estudados para definição dos circuitos mais adequados para o sistema de controle. O equipamento desenvolvido permite ajustar níveis de tensão e corrente elétricas, freqüência e largura de pulso do sinal de alimentação, de forma a possibilitar variações de emissão de luz nos dispositivos acionados. O sistema foi avaliado utilizando-se um mostrador de informações de PLEDs em matriz passiva, que antes passou por caracterizações estruturais e elétricas, sendo que os resultados serviram para ajuste da região de trabalho da tensão e corrente elétricas e freqüência de alimentação. Os resultados dos testes demonstraram que o circuito projetado atende a todos os requisitos de projeto e aos objetivos para os quais foi proposto. O acionamento do mostrador de referência com o sistema desenvolvido permitiu avaliar o seu desempenho em relação à emissão de luz, analisando características como luminância, cromaticidade e radiometria, frente a variações de tensão e corrente elétricas e largura de pulso do sinal de alimentação. Estas informações permitem a criação de uma base de dados que auxiliam o pesquisador durante a avaliação de desempenho e de reprodutibilidade de PLEDs ou mostradores de PLEDs construídos em laboratório. / In this work it is presented the study and development of an electronic system of test for performance evaluation of polymer light-emitting diodes - PLEDs, or displays with up to 35 PLEDs in passive-matrix produced in laboratory. The drive and control requirements, based in structural and electric characteristics of PLEDs and PLEDs displays, carefully had been studied for definition of adequate circuits for control system. The developed equipment allows adjusting voltage and current levels, frequency and pulse width of signal power, to make possible variations of light emission in the motion devices. The system was evaluated using passive-matrix PLED display, that before passed for structural and electric characterizations, being that the results had served for voltage, current and frequency adjustment of signal power. The tests results had demonstrated that projected circuit takes care of all requirements and objectives for which was considered. The drive of reference display with the developed system allowed to performance evaluate of its light-emitting characteristics, as luminance, chromaticity and photometry, front voltage, current and pulse width variations of signal power. This information allows a database creation that assists researcher during performance evaluation and reproducibility of PLEDs or PLEDs displays produced in laboratory.
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Light Emitting Diodes of Non-fully Conjugated Coil-like and Fully Conjugated Rigid-rod Heterocyclic Aromatic Homopolymers with Push-pull PendantsWen, Hong-ta 12 July 2008 (has links)
ABSTRACT
Light emitting diodes of non-fully conjugated coil-like homopolymers and fully conjugated rigid-rod homopolymers with electron withdrawing or donating group were studied. A series of Poly[2,2-(m-2-X-phenylene)-4-4¡A-hexafluoroisopropane- bibenzoxazoles] (6F-PBO-X, with X = amine, hydrogen and nitro) and poly-p-(2-X- phenylene)-benzobisoxazole (PBO-X, with X = amine, hydrogen and nitro) were synthesized for light emitting diode applications to observe electroluminescence emission affected by electron withdrawing or donating group.
All polymers were fabricated identically to form bi-layer light emitting diodes. In the devices, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonite)(PEDOT:PSS) was applied to be a hole transport layer; indium tin oxide (ITO) was the anode; and aluminum was the cathode.
Devices of the non-fully conjugated coli-like polymers (6F-PBO-X) and the fully conjugated rigid-rod polymers (PBO-X) all showed threshold voltage about 4 V. In the electroluminescence (EL) spectrum, the maximum intensity of non-fully conjugated polymer (6F-PBO-X) with amine (-NH2), hydrogen (-H) or nitro (-NO2) functional group was at 499 nm, 505 nm and 515 nm, respectively, showing a 20 nm wavelength shift. From ¡VNH2, -H and ¡VNO2 groups, their Commission International de l`Eclairage (C. I. E.) coordinates were (0.30, 0.46), (0.34, 0.45) and (0.40, 0.46), respectively. The EL maximum intensity for fully conjugated rigid-rod polymer PBO-X was at 521 nm (-NH2) and 474 nm (-NO2) showing a 50 nm wavelength shift. Their C. I. E. coordinates were (0.42, 0.45) and (0.25, 0.38), respectively. This is attributed to the fully conjugated, collinear, coplanar, rigid-rod polymers (PBO-X) backbone readily affected by the push-pull functional groups showing a large red shift.
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Desenvolvimento de um sistema eletrônico de acionamento e controle para avaliação de desempenho de mostradores de informações baseados em LEDs poliméricos. / Development of an electronic system of driver and control for perfomance evaluation of displays based on polymer LEDs.Fabio Henrique Pimentel 09 November 2007 (has links)
Neste trabalho é apresentado o estudo e o desenvolvimento de um sistema eletrônico de teste, para avaliação de desempenho de diodos emissores de luz poliméricos - PLEDs, ou de mostradores de informações com até 35 PLEDs em matriz passiva produzidos em laboratório. Os requisitos de acionamento e controle, baseados nas características estruturais e elétricas de PLEDs e mostradores de PLEDs, foram cuidadosamente estudados para definição dos circuitos mais adequados para o sistema de controle. O equipamento desenvolvido permite ajustar níveis de tensão e corrente elétricas, freqüência e largura de pulso do sinal de alimentação, de forma a possibilitar variações de emissão de luz nos dispositivos acionados. O sistema foi avaliado utilizando-se um mostrador de informações de PLEDs em matriz passiva, que antes passou por caracterizações estruturais e elétricas, sendo que os resultados serviram para ajuste da região de trabalho da tensão e corrente elétricas e freqüência de alimentação. Os resultados dos testes demonstraram que o circuito projetado atende a todos os requisitos de projeto e aos objetivos para os quais foi proposto. O acionamento do mostrador de referência com o sistema desenvolvido permitiu avaliar o seu desempenho em relação à emissão de luz, analisando características como luminância, cromaticidade e radiometria, frente a variações de tensão e corrente elétricas e largura de pulso do sinal de alimentação. Estas informações permitem a criação de uma base de dados que auxiliam o pesquisador durante a avaliação de desempenho e de reprodutibilidade de PLEDs ou mostradores de PLEDs construídos em laboratório. / In this work it is presented the study and development of an electronic system of test for performance evaluation of polymer light-emitting diodes - PLEDs, or displays with up to 35 PLEDs in passive-matrix produced in laboratory. The drive and control requirements, based in structural and electric characteristics of PLEDs and PLEDs displays, carefully had been studied for definition of adequate circuits for control system. The developed equipment allows adjusting voltage and current levels, frequency and pulse width of signal power, to make possible variations of light emission in the motion devices. The system was evaluated using passive-matrix PLED display, that before passed for structural and electric characterizations, being that the results had served for voltage, current and frequency adjustment of signal power. The tests results had demonstrated that projected circuit takes care of all requirements and objectives for which was considered. The drive of reference display with the developed system allowed to performance evaluate of its light-emitting characteristics, as luminance, chromaticity and photometry, front voltage, current and pulse width variations of signal power. This information allows a database creation that assists researcher during performance evaluation and reproducibility of PLEDs or PLEDs displays produced in laboratory.
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Studium optoelektrických vlastností tenkých vrstev organických polovodičů / Study of optoelectrical properties of organic semiconductor thin film layersPospíšil, Jan January 2012 (has links)
The thesis is focused on the study of electric and dielectric properties of thin film organic materials that can be used as an active layer of photovoltaic cells. Primarily were studied the properties of the layers on the glass substrates, which consist of a thin active layer of phthalocyanines. On the samples were first measured current-voltage characteristics (in the dark and during the exposure) and the basic parameters of the photovoltaic conversion were determined. Finally were measured frequency dependencies (impedance spectra, in the dark and during the exposure) and the parameters of a model of the structure with organic semiconductor were determined. The obtained results will be used to optimize the properties of photovoltaic cells.
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