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1
Langner, Maik. "Laterally modified microcavity systems containing organic emitters." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-67568.
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The scope of this work is an in-depth investigation of dielectric mirror microcavities with central organic dye layers, which are preferably modified in at least one lateral dimension. The large quality factor of the planar resonator in conjunction with comparatively stable and spectrally broad emitting molecules allows for a detailed analysis of several aspects of microresonator systems. Their optical properties are analyzed both with transmission and luminescence measurements as well as in the lasing regime.
The first part presents the resonant mode properties of planar and laterally structured microcavities. With the help of a high-resolution imaging micro-photoluminescence setup, working either in the spatial (near field) or vectorial (far field) regime, the polarization splitting is studied in a detuned microcavity, containing the dye 4,4'-bis[(N-carbazole)styryl]biphenyl (BSB-Cz) in a matrix of 4,4'-di(N-carbazolyl)- biphenyl (CBP). With the help of a thickness gradient, a relation between the large spectral distance of the cross-polarized states and the mode position within the stop band is investigated. In shadow-mask prepared, laterally restricted devices (5x5 µm2 square boxes), the three-dimensional confinement introduces sets of discrete modes, which experience a similar polarization splitting. The origin in this case is a different phase shift of electromagnetic waves during internal total reflection at a boundary.
By using a concentration gradient planar microcavity sample of the dye 4-(dicyanomethylene)-2-methyl-6-(4-(dimethylamino)styryl)-4H-pyran (DCM) in a tris-(8-hydroxyquinoline)aluminum (Alq3) matrix, the influence of the number of emitters on the lasing characteristics is subsequently analyzed. Depending on the pumping conditions, and thus the involvement of the Förster resonant energy transfer, an optimal composition is identified. After a qualitative evaluation of the long-term stability upon various excitation energies, the attention is focussed to the modification of the stimulated emission properties of photonic boxes. The stronger field concentration and altered density of states leads to a significant improvement of the values for the coupling factor fi and the threshold levels. Furthermore, new properties arise, namely simultaneous multimode and off-axis laser emission. With an inhomogeneous excitation of the box, it is possible to selectively excite single modes above the threshold.
The work ends with experimental results of metal structures as additional optical element in the organic microcavity layer. Here, the aim is is to understand the passive influence of these possible contact- devices on the lasing performance. For this purpose, the lasing is studied at an interface of an areal thin metal layer, which is incorporated in the organic layer.
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Jiang, Jinyue. "Design, Synthesis, and Properties of New Derivatives of Pentacene and New Blue Emitters." Bowling Green State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1145645147.
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Bachawala, Praveen. "Design, Synthesis and Properties of Corannulene Based Blue Emitters and Carcerands." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1368014057.
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Garrote, Cañas Ana Maria. "Design, synthesis and photophysical characterisation of N-containing organic emitters and their metal complexes." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/17251/.
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This study aimed to design novel N-containing heterocyclic compounds, utilising different synthetic strategies to tune the photophysical properties of these compounds. This research was focussed on three families of compounds: indoles, hydrazones and phenanthrolines. Hydrazones were proved to be useful precursors for the preparation of the bis(indoyl) derivatives via a double Fischer indole synthesis. Structural modifications and their effect on the photophysical properties were studied. Also, the pH response and metal sensing ability of these compounds were investigated. Despite the popularity of research involving indoles, a vast majority focusses on the development of new materials via functionalisation of the C-2 position. This thesis described two different strategies to modulate the photophysical properties of materials through a) structural modification of the organic framework aimed at altering its electron distribution and b) a use of metals aimed at the formation of organometallic complexes. Finally, the synthesis of five novel phenanthroline ligands was explored using two different strategies. Photophysical properties of the novel phenanthroline derivatives were investigated. Also, the synthesis of Ir(III) phenanthroline complexes was carried out and their photophysical properties were evaluated.
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Liu, Yuh-Shiuan. "Ultraviolet emitters grown by metalorganic chemical vapor deposition." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50415.
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This thesis presents the development of III-nitride materials for deep-ultraviolet (DUV) light emitting devices. The goal of this research is to develop a DUV laser diode (LD) operating at room temperature. Epitaxial structures for these devices are grown by metalorganic chemical vapor deposition (MOCVD) and several material analysis techniques were employed to characterize these structures such as atomic force microscopy, electroluminescence, Hall-effect measurement, photoluminescence, secondary ion mass spectrometry, transmission electron microscopy, transmission line measurement, and X-ray diffraction. Each of these will be discussed in detail. The active regions of III-nitride based UV emitters are composed of AlxGa1-xN alloys, the bandgap of which can be tuned from 3.4 eV to 6.2 eV, which allows us to attain the desired wavelength in the DUV by engineering the molar fraction of aluminum and gallium. In order to emit photons in the DUV wavelength range (> 4.1 eV), high aluminum molar fraction AlxGa1-xN alloys are required. Since aluminum has very low ad-atom mobility on the growth surface, a very low group V to group III precursor ratio (known as V/III ratio), high growth temperature, and low growth pressure is required to form a smooth surface and subsequently abrupt heterointerfaces. The first part of this work focuses on developing high-quality multi-quantum well structures using high aluminum molar fraction ([Al] > 60%) AlxGa1-xN alloys. Optically pumped DUV lasers were demonstrated with threshold power density as low as 250 kW/cm² for the emission wavelength as short as 248.3 nm. Transverse electric (TE) -like emission dominates when the lasers were operating above threshold power density, which suggests the diode design requires the active region to be fully strained to promote better confinement of the optical mode in transverse direction. The second phase of this project is to achieve an electrically driven injection diode laser. Owing to their large bandgap, low intrinsic carrier concentration, and relatively high dopant activation energy, the nature of these high aluminum molar fraction materials are highly insulating; therefore, efficiently transport carriers into active region is one of the main challenges. Highly conducting p-type material is especially difficult to achieve because the activation energy for magnesium, a typical dopant, is relatively large and some of the acceptors are compensated by the hydrogen during the growth. Furthermore, due to the lack of a large work function material to form a p-type ohmic contact, the p-contact layer design is limited to low aluminum molar fraction material or gallium nitride. Besides the fabrication challenges, these low aluminum molar fraction materials are not transparent to the laser wavelength causing relatively high internal loss (αi). In this work, an inverse tapered p-waveguide design is employed to transport holes to active region efficiently while the graded-index separate-confinement heterostructure (GRINSCH) is employed for the active region design. Together, a multi-quantum well (MQW) ultraviolet emitter was demonstrated.
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Langner, Maik [Verfasser], Karl [Akademischer Betreuer] Leo, and Uli [Akademischer Betreuer] Lemmer. "Laterally modified microcavity systems containing organic emitters / Maik Langner. Gutachter: Karl Leo ; Uli Lemmer. Betreuer: Karl Leo." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://d-nb.info/1067188452/34.
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Wada, Yoshimasa. "Molecular Design and Realization of Highly Efficient Thermally Activated Delayed Fluorescence Emitters for Organic Light-Emitting Diodes." Doctoral thesis, Kyoto University, 2020. http://hdl.handle.net/2433/253298.
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京都大学0048
新制・課程博士
博士(工学)
甲第22462号
工博第4723号
新制||工||1738(附属図書館)
京都大学大学院工学研究科分子工学専攻
(主査)教授 梶 弘典, 教授 佐藤 啓文, 教授 関 修平
学位規則第4条第1項該当
Doctor of Philosophy (Engineering)
Kyoto University
DFAM
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Mac, Ciarnaín Rossá [Verfasser], Torsten Gutachter] Fritz, Francesco [Gutachter] Michelotti, and Andreas [Gutachter] [Tünnermann. "Emission properties of small molecule phosphor emitters in organic light emitting diodes / Rossá Mac Ciarnaín ; Gutachter: Torsten Fritz, Francesco Michelotti, Andreas Tünnermann." Jena : Friedrich-Schiller-Universität Jena, 2017. http://d-nb.info/117760017X/34.
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Abdelhameed, Reda Mohamed. "Post-synthetic modification of metal–organic frameworks." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/15516.
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Doutoramento em QuímicaPost-synthetic modification (PSM) of metal-organic frameworks encompassing the chemical transformation of the linker present is a promising new route for engineering optical centres and tuning the light emission properties of materials, both in the visible and in the near infrared (NIR) spectral regions. Here, PSM of isoreticular metal-organic framework-3 (IRMOF-3) with ethyl oxalyl monochloride, ethyl acetoacetate, pentane-2,4-dione, 3-(2- hydroxyphenyl)-3-oxopropanal, 2-chloroacetic acid, glyoxylic acid, methyl vinyl ketone and diethyl (ethoxymethylene)malonate followed by chelation of trivalent lanthanide ions afforded intriguing near infrared (Nd3+) and visible (Eu3+, Tb3+) light emitters. IRMOF-3 was used as a case in point due to both its highly porous crystalline structure and the presence of non-coordinating amino groups on the benzenedicarboxylate (bdc) linker amenable to modification. The materials were characterised by elemental analysis, powder X-ray diffraction, optical, scanning and transmission electron microscopy, Fourier transform infrared spectroscopy, and liquid and solid-state nuclear magnetic resonance. The solid-state luminescence properties of Ln-modified-IRMOF-3 were investigated at room temperature. The presence of the bdc aromatic ring, β– diketonate and oxalate enhanced the Ln3+ sensitization via ligand-to-metal energy transfer (anthena effect). As far as photocalysis is concerned, we have synthesized metal−organic frameworks (Cr-MIL-125-AC, Ag-MIL-125-AC) by a green method (solid–vapors reactions). The resulting functionalized materials show a photocatalytic activity for methylene blue degradation up to 6.52 times larger than that of the commercial photocatalyst hombikat UV-100. These findings open the door for further research for improving the photocatalytic performance of metal-organic frameworks.
A modificação pós-síntese de estruturas metalo-orgânicas compreendendo na transformação do ligando orgânico presente é uma nova e promissora via para a engenharia de centros ópticos, permitido sintonizar as propriedades de emissão de luz de materiais na região do visível e do infravermelho próximo. Nesta dissertação, procedeu-se à modificação pós-sintética da estrutura isorreticular metal-orgânica-3 (IRMOF-3) com 2-cloro-2-oxoacetato de etilo, acetoacetato de etilo, pentano-2,4-diona, 3-(2-hidroxifenil)-3-oxopropanal, ácido 2-cloroacético, ácido glioxílico, metilvinil cetona e (etoximetileno)malonato de dietilo, seguida da quelação com iões lantanídeos trivalentes, a qual originou interessantes emissores de luz na região do infravermelho próximo (Nd3+) e do visível (Eu3+, Tb3+). O IRMOF-3 foi usado como um caso de estudo devido quer à sua a estrutura cristalina que apresenta considerável microporosidade, quer à presença de grupos amino livres no ligando benzenodicarboxilato (bdc), que são passíveis de modificação. Os materiais foram caracterizados por análise elementar, difracção de raios X de pós, microscopias óptica, electrónica de varrimento e de transmissão, espetroscopias de infravermelho com transformadas de Fourier e de ressonância magnética nuclear (estados líquido e sólido). As propriedades de luminescência dos materiais Ln-IRMOF-3-modificados foram estudadas à temperatura ambiente. A presença do anel aromático bdc, β- dicetonato e oxalato reforça a sensibilização do Ln3+ através da transferência de energia do ligando para o metal (efeito antena). No que respeita à fotocatálise, sintetizaram-se novos materiais metal-orgânicos (Cr-MIL-125-AC, Ag-MIL-125-AC) através de uma reação sólido-vapor. Estes materiais apresentam uma excelente atividade fotocatalítica para a degradação de azul de metileno até 6,52 vezes maior que o fotocatalisador comercial hombikat UV- 100. Estes resultados abrem a porta a novos estudos que visam melhorar a actividade fotocatalítica de materiais metalo-orgânicos.
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Jakoby, Marius Felix [Verfasser], and B. S. [Akademischer Betreuer] Richards. "Investigating Exciton Dynamics by Photoluminescence Quenching Experiments in Metal-Organic Frameworks and Thermally Activated Delayed Fluorescence Emitters / Marius Felix Jakoby ; Betreuer: B. S. Richards." Karlsruhe : KIT-Bibliothek, 2021. http://d-nb.info/1231361514/34.
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Wong, Michael Yin. "Creating novel thermally activated delayed fluorescence (TADF) emitters for light-emitting electrochemical cells (LEECs) and organic light-emitting diodes (OLEDs) applications and their structure-property relationship." Thesis, University of St Andrews, 2017. http://hdl.handle.net/10023/12975.
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Developing organic light-emitting diodes (OLEDs) as the next generation display devices is not only of industrial interest, but also a scientific challenge in and of itself that requires multi-disciplinary efforts to make the technology successful. Thermally activated delayed fluorescence (TADF) is a recent breakthrough in OLED technology whose prime value is to enable purely organic emitters to recruit the dark triplet excitons in the device, thus avoiding expensive and toxic rare metal based emitters. This thesis is centred on TADF and contains work in three major areas. Firstly, novel ionic TADF emitters were designed for use in light-emitting electrochemical cells (LEECs), which is an alternative electroluminescent device technology to OLEDs, with a much simplified fabrication procedure and architecture. The vast majority of these ionic emitters are based on reported TADF scaffolds where the donors were tethered with an imidazolium hexafluorophosphate group to obtain the ionic character required for LEEC devices (TL and BTL series, Chapter 2). On the other hand, TADF emitters with a carboxylate group were also designed which act as both acceptor and intrinsic charged functionality for LEEC applications (CTL series, Chapter 2). Secondly, attempts were made to create novel TADF molecular scaffolds in order to enrich the current library of TADF emitters. Research efforts were focused on polyaromatic moieties such as anthracene (An series, Chapter 4) and fluoranthene (FA series, Chapter 4) that are seldom reported in TADF literature. In addition, TADF emitters with phosphine oxide as the acceptor group have also been studied (PO series, Chapter 5). Lastly, structure-property relationship studies of TADF emitters were undertaken as a function of tuning of donor and acceptor functionalities using both theoretical and experimental approaches in order to gain more insight for designing desirable TADF emitters (Chapter 3).
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KARAMSHUK, SVITLANA. "Organic sensitizers for application in photonic and photovoltaic devices." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2015. http://hdl.handle.net/10281/76622.
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With the increasing demand for reliable and efficient devices with minimal environmental impact, novel organic materials gain extreme interest in the research community and industry. In this work we present synthetic strategies towards new organic compounds as promising materials for dye sensitized solar cells (DSCs) and low-cost integrated optics along with the investigation of these materials in devices.
Despite the recent hype in the research community around DSCs, increasing efficiency of DSCs is still a challenge. In principle, one promising way to obtain DSCs with significantly enhanced efficiency lies in connecting an n-type photoelectrode (i.e. n-Dye/TiO2) with a p-type one (i.e. p-Dye/NiO) leading to a tandem cell composed by two serially connected photoactive electrodes, each contributing with its own photovoltage to the total photovoltage delivered by the cell. Applying such concept could theoretically lead to organic photovoltaic devices with up to 40% overall conversion yield. One of the main limitations in p-type systems, commonly based on NiO, arises from fast charge recombination between the photoinjected hole in NiO, and the reduced dye. Therefore it is crucially important to develop p-type chromophores which could produce a long-lived charge separated state and minimize back recombination.
We were thus triggered to explore new organic structures for potentially efficient chromophores for p-type devices, by considering that the intramolecular charge transfer, at the basis of efficient charge separation in donor-acceptor dyes, is strongly dependent on the electron-withdrawing ability of the acceptor. Herein we present charge separators based on organic push-pull systems of tryphenylamine donors and branched electron acceptors (SK2-3-4) based either on Dalton (SK2) or benzothidaziole acceptor groups (SK3-4) which were synthesized and characterized by steady state spectroscopic, electrochemical and computational means. All the dyes exhibit strong charge transfer bands in the visible regions with ground and excited state energetics which are favourable to the sensitization of NiO electrodes. The computational investigation revealed a clear directionality of the lowest excited state exhibiting a marked charge transfer character, shifting the electron density to the acceptor branches, an electronic situation which is favourable to the hole injection in p-type semiconductors. When tested in p-type DSCs the SK series was found capable to sensitize NiO electrodes. The charge recombination kinetics, probed by considering the charge transfer resistance at the NiO/electrolyte interface at a comparable chemical capacitance, showed that the dyes behaved similarly and that the higher Voc observed with the SK4 dye is ostensibly due to a positive shift of the valence band edge, consistent with the shift in the anodic current threshold observed in dark conditions.
The second part of this work is dedicated to synthesis and characterisation of metallo-organic materials for optoelectronic devices. Optical amplification plays crucial role in the transmission and manipulation of optical signals in modern telecomunications. Nowadays amplifiers, which rely on erbium ions in a glass matrix, suffer from difficulties in fabrication and the need of high pump power densities to produce gain. Here we show a newly synthesised series of organic fully halogenated optical amplifier materials.
We will compare the ability of materials with different halogen atoms in complexes with transition metals to provide population of triplets which together with the lack of CH or OH oscillators in the molecule, can be potentially used as an efficient chromophore to sensitise the erbium ions in a long-lifetime erbium complex. Finally by doping Er(FTPIP)3 with newly designed Zn and Co complexes, we aim to find differences in the lifetime emission from erbium at the important telecommunication wavelength of 1.5 μm.
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Zhang, Shuyu. "Directional organic light-emitting diodes using photonic microstructure." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/6356.
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This thesis describes investigations into the optical and device design of organic light-emitting diodes (OLEDs) with the aim of exploring the factors controlling the spatial emission pattern of OLEDs and developing novel OLEDs with directional emission by applying wavelength-scale photonic microstructure. The development of directional OLEDs was broken down into two steps: the development of efficient narrow linewidth OLEDs and the integration of wavelength-scale photonic microstructures into narrow linewidth OLEDs. The narrow linewidth OLEDs were developed using europium (Eu) complexes. The electrical optimisation of solution-processed Eu-based OLEDs using commercially available materials was investigated. The optimised Eu-based OLEDs gave an external quantum efficiency of 4.3% at a display brightness of 100 cd/m². To our knowledge, this is the highest efficiency reported for solution-processed Eu-based OLED devices, and the efficiency roll-off has been reduced compared with other reported references. Photonic microstructures were applied to develop directional OLEDs using the efficient Eu-based OLEDs. Two contrasting strategies were used. One was to embed photonic microstructures into Eu-based OLEDs, the other was to couple photonic microstructures externally onto the devices. The microstructured devices developed by the former strategy boosted the emitted power in desired angles in both s- and p-polarisations and doubled the fraction of emission in an angle range of 4⁰. The devices developed by the external coupling strategy achieved even higher directionality and the out-coupled emission was a confined beam with easy control of beam steering. Around 90% of the emitted power was confined in an angular range of 20⁰ in the detection plane. The optical properties can be optimised independently without compromising the electrical properties of devices, which gives major advantages in terms of effectiveness and versatility. Optical models were also developed to investigate the out-coupling mechanism of various trapped modes and develop OLEDs with stronger directionality.
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Dahlen, Joseph. "REDUCTION OF VOLATILE ORGANIC COMPOUNDS EMITTED DURING KILN DRYING OF SOUTHERN YELLOW PINE LUMBER." MSSTATE, 2008. http://sun.library.msstate.edu/ETD-db/theses/available/etd-10172008-085347/.
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The objective of the research is to reduce the volatile organic compounds (VOCs) emitted during kiln drying of southern yellow pine (SYP) lumber. Three treatment methods were explored to determine their effect on VOC emissions. The three methods were configured at the air exhaust of a pilot-scale dry kiln. 1) A steel reactor containing copper tubing heated to 100°, 200°, and 240° Celsius was evaluated. Temperature did not statistically affect VOC emissions (p-value = 0.1674). The average reduction of VOCs at 240° C was seven percent. 2) The use of hydrogen peroxide and ultra-violet (UV) light did not reduce VOCs emitted during kiln drying. 3) The use of Fenton?s reagent, with hydrogen peroxide and ferrous sulfate, also did not reduce VOCs emitted during kiln drying. 4) It is recommended that future studies with copper heated to temperatures above 240° C be performed.
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Brown, Veronica M. "Development of improved methods for the characterisation of organic chemicals emitted into indoor air by building and furnishing products." Thesis, Cranfield University, 2013. http://dspace.lib.cranfield.ac.uk/handle/1826/8078.
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A wide range of organic compounds are released from building and furnishing products and these have the potential to adversely affect indoor air quality. There are growing international requirements for testing and controlling these emissions for the protection of public health. The test methods require specialist analytical chemistry facilities based on thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS). This project has addressed the need for better performance and greater automation of the analysis, as well as development of simpler screening tests. A variety of products were tested using screening techniques, with an emission cell method being used as a reference test. Short duration tests, using a micro-scale chamber at slightly elevated temperature, were shown to have the potential to predict emissions occurring during longer term reference tests. Multi-sorbent air sampling tubes, that have the potential to extend the volatility range of compounds determined by a single TD/GC/MS analysis, were compared with Tenax TA tubes specified by current standard methods. This showed no difference in performance for the range of compounds for which Tenax is optimal, with improved performance for a number of more volatile compounds. The determination of formaldehyde was investigated using 2-hydroxymethylpiperidine as a derivatising agent, followed by TD/GC/MS. The results showed the possibility of this method being developed as an alternative to the current standard method that involves solvent elution and liquid chromatography. The performance of a newly developed time-of-flight mass spectrometer was compared with a standard quadrupole instrument. This showed its potential, with the use of re-collection, to extend the concentration range of compounds quantified from a single air sample, of particular benefit for the determination of carcinogens. New compound identification software was applied to increase automation of analysis of the TD/GC/MS data. Good correlation with manual processing was achieved, demonstrating the possibility of routine application to material emissions testing.
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ASTI, Mattia. "SYNTHESIS AND QUALITY ASSESSMENT OF THE POSITRON EMITTER RADIOTRACER 2-[18F]-FLUOROETHYLCHOLINE, A [18F]-LABELLED CHOLINE ANALOGUE FOR TUMOURS IMAGING." Doctoral thesis, Università degli studi di Ferrara, 2013. http://hdl.handle.net/11392/2388919.
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Introduction: [18F]-labelled choline analogues, such as 2-[18F]-Fluoroethylcholine ( [18F]-FECH ), have
suggested to be the new generation of choline derivatives for the imaging of prostate and brain
tumours. In fact, tumour cells with enhanced proliferation rate exhibit an improved choline uptake due
to the increased membrane phospholipids biosynthesis. The aim of this dissertation is the development
and validation of a reliable automatic synthesis of [18F]-FECH. Moreover, in order to assure a safe
employment of the radiotracer in a research clinical trial, particular attention was paid to establish the
proper quality controls required.
Materials and Methods: [18F]-FECH was synthesized with varying synthetic approaches (one step and
two steps reaction, preparative HPLC or solid phase extraction purification) and by using two different
automatic synthesizers (FXF-N Tracer Lab Synthesizer and Mx Tracer Lab). In the first step, cyclotron
produced [18F]-Fluoride was reacted for 5 minutes at 80°C, with a 20 mg/ml solution of 1,2-
bis(tosyloxy)ethane (diOTsEt) in acetonitrile in order to obtain the [18F]-EtOTs intermediate. The
reaction was performed in anhydrous condition and in presence of tetrabutylammonium (TBA) as
transfer phase catalyst. In the second step, without any further purification, [18F]-EtOTs was reacted for
10 minutes at 100° C in the same reactor, with a 88.6 mg/ml solution of N,N-dimethylethanolamine
(DMAE) in acetonitrile. The reaction mixture was then purified by SPE or HPLC and then eluted with
16 ml of physiological solution. The effect of different precursors (Br2Et, diNosEt and BrOtsEt) on the
reactions was also assessed but with lower success. Quality controls on the final product were
performed by means of TLC, GC and HPLC equipped with conductimetric, UV and radiometric
detectors. Sterility and absence of bacterial endotoxin were assessed by following the European
Pharmacopeia guidelines.
Results: [18F]-FECH was prepared with a yield between 17±2 and 41 ±2 % uncorrected for decay in a
time ranging between 33 and 55 minutes, depending on the synthetic approach and on the synthesizer
used. Radiochemical purity was always greater than 99 % with both free [18F]-fluoride and [18F]-EtOTs
less than 0.5 % of the total radioactivity. The DMAE concentration always resulted less than 15 mg/L
and was detected with either GC or HPLC with conductimetric detection. The main chemical impurity
was due to dimethylmorpholinium (dMM), a cationic by-product derived from the direct reaction and
cyclization of diOTsEt and DMAE. The dMM concentration was detected by HPLC with
conductimetric detection and always resulted less than 180 mg/L. The absence of tosylated by-products
or free OTs- anions was assessed by HPLC with UV detection. Residual solvents and TBA
concentrations respected the limits fixed for an injectable radiopharmaceutical preparation and were
detected by means of GC in the same analysis conditions used for DMAE. All the sample analyzed
were sterile.
Conclusions: [18F]-FECH radiopharmaceutical was synthesized with an high yield and radiochemical
purity by using a automatic synthesizers. The complete elimination of the dMM by-product from the
final solution was not possible by means of a solid phase extraction as a purification method. A
research clinical trial was activated and, up to now, more than 150 patients were safely examined.
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Scarpellini, M. "ADVANCED MATERIALS: PREPARATION, STUDY AND OPTIMIZATION OF THIN FILM FOR OPTO-ELECTRONIC DEVICE." Doctoral thesis, Università degli Studi di Milano, 2010. http://hdl.handle.net/2434/150151.
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The term “optoelectronic devices” is by now used for devices in which both electrons and photons are essential for their operation, as a natural evolution from the definitions of electronic devices that involved only electrons and holes in their operation and of photonic devices that involved only photons in their operation. One of the new lighting technologies which emerged within the past two decades and has the potential of becoming more energy-efficient then the existing light sources, is the Solid State Lighting technology of Organic Light Emitting Diodes (OLEDs). In general, the basic OLED structure consists of a stack of fluorescent organic layers sandwiched between a transparent conducting anode and metallic cathode. When an appropriate current is applied to the device, holes are injected from the anode and electrons from the cathode; some of the recombination events between the holes and electrons result in electroluminescence (EL). The first part of this PhD Thesis surveyed different aspect in OLED technology that are currently under debate. In particular chapter 2 is devoted to the study, preparation and optimization of thin films between the organic hole transport layer and the anode surface while chapter 3 deals with the synthesis of trifluorene compound, with methoxy substituents, as possible UV-blue emitter. The second part of this PhD work is dedicated to the synthesis and study of new materials with interesting emissive and second order NLO properties. In particular pyrene based chromophores are investigated in chapter 4, while chapter 5 deals with the synthesis of organic-inorganic perylene-POSS hybrids with enhanced emissive properties.
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Makarow, Ramona Irina Gloria Fanny [Verfasser], Niko [Akademischer Betreuer] Balkenhol, Niko Gutachter] Balkenhol, and Peter [Gutachter] [Kaul. "Identification of the specific volatile organic compounds emitted by Anoplophora glabripennis (Moschulsky) / Ramona Irina Gloria Fanny Makarow ; Gutachter: Niko Balkenhol, Peter-Michael Kaul ; Betreuer: Niko Balkenhol." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://nbn-resolving.de/urn:nbn:de:gbv:7-21.11130/00-1735-0000-0005-137F-8-5.
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Makarow, Ramona Irina Gloria Fanny [Verfasser], Niko [Akademischer Betreuer] Balkenhol, Niko [Gutachter] Balkenhol, and Peter-Michael [Gutachter] Kaul. "Identification of the specific volatile organic compounds emitted by Anoplophora glabripennis (Moschulsky) / Ramona Irina Gloria Fanny Makarow ; Gutachter: Niko Balkenhol, Peter-Michael Kaul ; Betreuer: Niko Balkenhol." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://d-nb.info/1208918427/34.
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Schreil, Manfred. "Erzeugung großflächiger organischer Leuchtdioden in einem vertikalen In-Line-Bedampfungssystem." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2005. http://nbn-resolving.de/urn:nbn:de:swb:14-1119355576183-77424.
Full textAbstract:
Im Mittelpunkt der vorliegenden Dissertation stand die Herstellung von organischen Leuchtdioden und Passiv-Matrix-Displays an einer neuartigen Durchlauf-Depositionsanlage. Die Abscheidung von "small molecule" Materialien im Hochvakuum wurde dabei mittels organischer Molekularstrahldeposition (OMBD) durchgeführt. Um effiziente Leuchtdioden zu erzielen, sind die Bauelemente als Mehrschichtsystem aufgebracht worden. Als Grundstruktur kam eine Schichtenfolge zur Anwendung, die als Löchertransporter aus dem Starburst-Derivat 2-TNATA, daran anschließend einem tertiären Arylamin, dem elektronenblockierenden a-NPB sowie dem Oxinat-Komplex Alq3 besteht. Dabei diente das Aluminium-Oxinat als Elektronenleiter und Emissionsmaterial. Mit dem Quinacridon-Derivat QAD als Dotierstoff wurde außerdem eine OLED-Struktur mit Gast-Wirtsystem realisiert Eine kontrollierte und reproduzierbare Deposition der organischen Materialien ist eine unabdingbare Voraussetzung, um organische Leuchtdioden kommerziell als Mehrschichtbauelemente herstellen zu können. Dazu wurde ein Hochvakuumsystem der Firma Applied Films installiert und in Betrieb genommen. Die VES 400/13-Entwicklungsanlage ist als Vertical Evaporation and Sputtering Durchlaufsystem für bis zu 400 mm hohe Substrate mit 11 individuellen Prozesskammern sowie zwei daran anschließenden Stickstoffboxen konzipiert. Diese Technologie ermöglicht das Aufdampfen einer oder nacheinander mehrerer Schichten auf beliebiges Substratmaterial. Entsprechend den Erfordernissen sind wichtige Prozessparameter wie Depositionsrate, Transportgeschwindigkeit des Substrates sowie Filmdicke der funktionellen Schichten in einem weiten Bereich frei einstellbar. Neben einer ausgeglichenen Löcher- und Elektroneninjektion werden die Eigenschaften der hergestellten Leuchtdioden durch die Dicken der einzelnen Schichten, der Beweglichkeit der Ladungsträger in den verwendeten organischen Materialien sowie der energetischen Lage der höchsten besetzten und niedrigsten unbesetzten Molekülorbitale der Halbleiter bestimmt. Als undotierte OLED-Struktur wurde eine Schichtenfolge aus ITO / 2-TNATA / NPB / Alq3 / Mg verwendet. Die Stärke der elektrischen Kontakte betrug jeweils etwa 150 nm für ITO bzw. Magnesium. Die organischen Halbleiterfilme verfügten über Lagendicken von 60 / 10 / 60 nm. Eine derart aufgebaute Leuchtdiode zeigte ein grünes Emissionsspektrum, dessen Mittenwellenlänge bei etwa 537 nm lag und eine Halbwertsbreite von circa 112 nm aufwies. Für die Betriebsspannung, die Leuchtdichte, die Strom- sowie die Leistungseffizienz ergaben sich für die beiden Stromdichten von 3 mA/cm² und 30 mA/cm² optimierte Werte zu 5,3 V bzw. 9,4 V, 100 cd/m² bzw. 1317 cd/m², 3,3 cd/A bzw. 4,4 cd/A sowie 2 lm/W bzw. 1,5 lm/W. Das Sperr- oder Gleichrichtungsverhältnis Gv wurde für die beiden gemessenen Maximal-spannungen von ±10 Volt zu <5 x 107 bestimmt. Durch die Dotierung der Alq3-Emissionsschicht mit etwa 1 mol% des Quinacridon-Derivats QAD und Hinzufügen einer separaten Elektronentransportschicht konnte eine Steigerung der Elektrolumines-zenz erreicht werden. Der OLED-Aufbau des Gast-Wirt-Systems verfügt über einen Schichtenstapel mit den Lagen ITO / 2-TNATA / NPB / Alq3 + QAD / Alq3 / Mg. Die Filmdicken der organischen Schichten der OLED mit den besten Eigenschaften betragen 60 / 10 / 35 / 25 nm. Die anorganischen elektrischen Kontakte waren jeweils etwa 150 nm dick. Die dotierten Bauelemente zeigen ein bei einer Mittenwellenlänge von 527 nm emittierendes, grünes Spektrum. Mit einer geringen Halbwertsbreite von 28 nm ist die Bedingung einer schmalen Emissionsbreite für die Anwendung in OLED-Displays erfüllt. Die Betriebsspannung, die Leuchtdichte, die Strom- und die Leistungseffizienz ergeben für die beiden Stromdichten von 6,2 mA/cm² und 45,6 mA/cm² optimierte Werte zu 10,8 V bzw. 17,0 V, 445,4 cd/m² bzw. 3816,7 cd/m², 7,2 cd/A bzw. 8,4 cd/A sowie 2,1 lm/W bzw. 1,6 lm/W.
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Wu, Fang-Iy, and 吳芳奕. "Molecular and Polymeric Emitters for Organic-Light." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/42509747035430935480.
Full textAbstract:
博士國立交通大學
應用化學系所
94
The work presented here describes the chemistry and the device applications of small molecule-based and polymer-based emitters with improved thermal stability. Chapter one briefly introduces the history of organic electroluminescence and how these devices work; chapter two summaries the experiement section of synthetic routes and the characterization methods of these emitters. 4,4´-bis(2,2-diphenylvinyl)-1,1´-biphenyl (DPVBi) has been proved to be one of the most promising blue emitter because of its high photoluminescence (PL) efficiency in solid-state. However, the deposited films of DPVBi have a strong tendency to crystallize, which hinders its applications in OLEDs (organic light-emitting diodes). Chapter three describes the synthesis and characterization of the spirobifluorene-based DPVBi analogue, DPVSBF, in which the bis(2,2-diphenylvinyl) groups are connected through the 2 and 7 positions of the spirobifluorene framework. DPVSBF possess a high glass transition temperature (Tg) of 115 ℃ and enhanced morphological stability in comparison with DPVBi. The DPVSBF-based device exhibits a 16-fold enhancement in the operation lifetime relative to that of a similar device based on DPVBi. In chapter four, we further prepared a serial of DPVBi analogues based on carbazole-core in attempt to realize distyrylcarbazole compounds served as blue light-emitting and hole-transporting materials for OLED applications. In a simple double-layer device configuration, the distyrylcarbazole materials exhibited lower turn-on voltages and more efficient blue light than those obtained from the DPVBi-based device. In a phosphorescent dye-doped polymeric light emitting diodes, two different operating mechanisms, energy transfer and direct charge trapping, can lead to the phosphorescence of dopants. In chapter five, we have realized the preparation of highly efficient red-electrophosphorescent devices (maximum external quantum efficiency, EQEmax ~ 8.5%) incorporating Ir or Os complexes at low doping contents by using blue polyfluorene copolymers with built-in charge-transporting side chains (PF-OXD and PF-TPA-OXD), in which the direct charge trapping on dopant sites is the main operating mechanism. The absence of charge-transporting pendent units—i.e., the device fabricated from poly[9,9-dioctylfluorene-2,7-diyl] (POF)—led, however, to relatively poor electroluminescence characteristics (5.81% and 2144 cd/m2) In chapter six, we report a bipolar charge-transporting copolymer, PFA-OXD, which possesses electron-rich fluorene-triphenylamine backbones and electron-deficient oxadiazole pendent groups. This polymer exhibited a very high glass transition temperature (306 °C) and good thermal stability, without sacrificing its good solution processability. According to the performances of the electroluminescent devices, PFA-OXD is not only an efficient blue emitter (EQEmax = 1.59 %) but also a good polymeric host for red phosphor (EQEmax = 9.30 %).
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Langner, Maik. "Laterally modified microcavity systems containing organic emitters." Doctoral thesis, 2010. https://tud.qucosa.de/id/qucosa%3A25550.
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The scope of this work is an in-depth investigation of dielectric mirror microcavities with central organic dye layers, which are preferably modified in at least one lateral dimension. The large quality factor of the planar resonator in conjunction with comparatively stable and spectrally broad emitting molecules allows for a detailed analysis of several aspects of microresonator systems. Their optical properties are analyzed both with transmission and luminescence measurements as well as in the lasing regime.
The first part presents the resonant mode properties of planar and laterally structured microcavities. With the help of a high-resolution imaging micro-photoluminescence setup, working either in the spatial (near field) or vectorial (far field) regime, the polarization splitting is studied in a detuned microcavity, containing the dye 4,4'-bis[(N-carbazole)styryl]biphenyl (BSB-Cz) in a matrix of 4,4'-di(N-carbazolyl)- biphenyl (CBP). With the help of a thickness gradient, a relation between the large spectral distance of the cross-polarized states and the mode position within the stop band is investigated. In shadow-mask prepared, laterally restricted devices (5x5 µm2 square boxes), the three-dimensional confinement introduces sets of discrete modes, which experience a similar polarization splitting. The origin in this case is a different phase shift of electromagnetic waves during internal total reflection at a boundary.
By using a concentration gradient planar microcavity sample of the dye 4-(dicyanomethylene)-2-methyl-6-(4-(dimethylamino)styryl)-4H-pyran (DCM) in a tris-(8-hydroxyquinoline)aluminum (Alq3) matrix, the influence of the number of emitters on the lasing characteristics is subsequently analyzed. Depending on the pumping conditions, and thus the involvement of the Förster resonant energy transfer, an optimal composition is identified. After a qualitative evaluation of the long-term stability upon various excitation energies, the attention is focussed to the modification of the stimulated emission properties of photonic boxes. The stronger field concentration and altered density of states leads to a significant improvement of the values for the coupling factor fi and the threshold levels. Furthermore, new properties arise, namely simultaneous multimode and off-axis laser emission. With an inhomogeneous excitation of the box, it is possible to selectively excite single modes above the threshold.
The work ends with experimental results of metal structures as additional optical element in the organic microcavity layer. Here, the aim is is to understand the passive influence of these possible contact- devices on the lasing performance. For this purpose, the lasing is studied at an interface of an areal thin metal layer, which is incorporated in the organic layer.:List of publication
Introduction
Optical properties of dielectric microresonator systems
Sample fabrication and characterization
Resonant mode properties of dielectric mirror microcavities
Lasing from laterally modified organic cavity systems
Conclusion and outlook
Bibliography
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Yang, Cheng-Hsien, and 楊正憲. "Red and Green Emitters for Organic Light-Emitting Diodes." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/72117075946373964507.
Full textAbstract:
博士國立成功大學
化學系碩博士班
94
Organic light-emitting diodes (OLEDs) have potentials for application in the flat panel display and have received vast attentions. This work focuses on synthesizing various green and red phosphorescent emitters based on iridium complexes. Firstly, four novel red phosphorescent emitter compounds bis(1-phenyl- isoquinolinato-N,C2’)iridium(acetylacetonate), (piq)2Ir(acac), bis(1-(1’naphthyl) isoquinolinato-N,C2’)iridium(acetylacetonate), (1-niq)2Ir(acac), bis(1-(2’-naphthyl) isoquinolinato-N,C2’)iridium(acetylacetonate), (2-niq)2Ir(acac), and bis(1-phenyl- 5-methyl-isoquinolinato-N,C2’)iridium(acetylacetonate), (m-piq)2Ir(acac), have been synthesized and fully characterized. Electroluminescent devices with a configuration of ITO / NPB / CBP : Dopant / BCP / AlQ3 / LiF / Al were fabricated. All devices emitted in the red region with an emission ranging from 624nm to 680nm. (m-piq)2Ir(acac) shows a maximum brightness of 17164 cd/m2 at a current density of J = 300 mA/cm2 and the best luminance efficiency of 8.91 cd/A at a current density of J = 20 mA/cm2. (1-niq)2Ir(acac) exhibits pure-red emission with 1931 CIE (Commission International de L’Eclairage) chromaticity coordinates (x=0.701, y=0.273). Secondly, novel red phosphorescent emitter bis(4-phenylquinazolinato-N,C2’) iridium(acetylacetonate) [(pqz)2Ir(acac)], bis(1-(1’-naphthyl)-5-methylisoquinolin ato-N,C2’)iridium(acetylacetonate) [(1-mniq)2Ir(acac)] and bis(1-(2’-naphthyl)- 5-methylisoquinolinato-N,C2’)iridium(acetylacetonate) [(2-mniq)2Ir(acac)] have been synthesized and fully characterized. The electronegative effect of (pqz)2Ir(acac) ligand shows almost the same influence as the extended π-conjugation effect of (2-mniq)2Ir(acac). Density functional theory (DFT) was applied to calculate the Kohn-Sham orbitals of HOMOs and LUMOs in the iridium complexes to illustrate the N(1) electronegative atom effect. Finally, lowest triplet state (T1) energies calculated by time-dependent DFT (TDDFT) were compared with the experimental electroluminescent data. The calculated data for the iridium complexes agreed fairly well with experimental data. Electroluminescent devices with a configuration of ITO / NPB / CBP : dopant / BCP / AlQ3 / LiF / Al were fabricated. The device using (pqz)2Ir(acac) as a dopant showed deep-red emission with 1931 CIE (Commission International de L’Eclairage) chromaticity coordinates x = 0.70, y = 0.30. Thirdly, we developed a new process at high vacuum (5×10-5 torr) and high temperature (300℃) to produce meridional iridium complexes from the dimer; interestingly, mer-Ir(m-ppy)3 overthrows the concept of poor efficiency and shows excellent efficiency that is almost equal to fac-Ir(ppy)3, fac-Ir(m-ppy)3 and (ppy)2Ir(acac). In this approach, we have found that mer-Ir(m-ppy)3 in fact results in a blue shift with respect to fac-Ir(ppy)3 and produces a fairly pure green emission. Electroluminescent devices with a configuration of ITO / NPB / CBP : dopant / BCP / AlQ3 / LiF / Al were fabricated. The device using mer-Ir(m-ppy)3 as a dopant showed green emission with 1931 CIE (Commission International de L’Eclairage) chromaticity coordinates x = 0.31, y = 0.59. This result suggests us a new direction in developing novel emitter for OLEDs.
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Neal, Terrell Demetris. "Surface Plasmon Enhanced Light Emission from Organic Light Emitters." Thesis, 2006. https://thesis.library.caltech.edu/3698/1/Terrell_D_Neal.pdf.
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We have experimentally verified that visible light emission for various organic light emitters can be enhanced through the use of surface plasmon coupling layers. By matching the plasmon frequency of a thin unpatterned silver film to the emission of a dye-doped polymer deposited onto this metal surface, we have observed an 11-fold enhancement of light emission. By patterning the silver layer, we estimate that the plasmon frequency can be tuned to match dye-doped polymer emission frequencies, and even larger emission enhancements as well as extraction efficiencies are expected. Carrier dynamics of such plasmon-enhanced organic light emitters were studied and a recombination rate increase due to surface plasmon polaritons was experimentally observed. Internal quantum efficiency data from the polyfluorenes studied follow the trend supported by the time-resolved photoluminescence measurements. Also, we have presented a way to extend the lifetime of organic light emitters by reducing the photodegredation effects from photo-oxidation using surface plasmon coupling.
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"New Materials and Device Designs for Organic Light-Emitting Diodes." Doctoral diss., 2017. http://hdl.handle.net/2286/R.I.44068.
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abstract: Research and development of organic materials and devices for electronic applications has become an increasingly active area. Display and solid-state lighting are the most mature applications and, and products have been commercially available for several years as of this writing. Significant efforts also focus on materials for organic photovoltaic applications. Some of the newest work is in devices for medical, sensor and prosthetic applications.
Worldwide energy demand is increasing as the population grows and the standard of living in developing countries improves. Some studies estimate as much as 20% of annual energy usage is consumed by lighting. Improvements are being made in lightweight, flexible, rugged panels that use organic light emitting diodes (OLEDs), which are particularly useful in developing regions with limited energy availability and harsh environments.
Displays also benefit from more efficient materials as well as the lighter weight and ruggedness enabled by flexible substrates. Displays may require different emission characteristics compared with solid-state lighting. Some display technologies use a white OLED (WOLED) backlight with a color filter, but these are more complex and less efficient than displays that use separate emissive materials that produce the saturated colors needed to reproduce the entire color gamut. Saturated colors require narrow-band emitters. Full-color OLED displays up to and including television size are now commercially available from several suppliers, but research continues to develop more efficient and more stable materials.
This research program investigates several topics relevant to solid-state lighting and display applications. One project is development of a device structure to optimize performance of a new stable Pt-based red emitter developed in Prof Jian Li's group. Another project investigates new Pt-based red, green and blue emitters for lighting applications and compares a red/blue structure with a red/green/blue structure to produce light with high color rendering index. Another part of this work describes the fabrication of a 14.7" diagonal full color active-matrix OLED display on plastic substrate. The backplanes were designed and fabricated in the ASU Flexible Display Center and required significant engineering to develop; a discussion of that process is also included.Dissertation/Thesis
Doctoral Dissertation Materials Science and Engineering 2017
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Chein, Chen-Han, and 簡辰翰. "Molecular Emitters Containing Charge Transporting Units for Organic Electroluminescent Devices." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/80479979305008571786.
Full textAbstract:
博士國立交通大學
應用化學系碩博士班
99
In this thesis, the central idea is to develop materials for OLEDs, which will be utilized in the improvement of electrophosphorescence as well as electrofluorescence. The study is divided into two sub topics as following: (1)Studies of host materials with bipolar characteristics In part A, a solution-processable bipolar material tBu-OXDTFA comprising an electron-rich triphenylamine core and electron-deficient oxadiazole/fluorene peripheries was synthesized. This dendrimer-like molecule not only possesses a high triplet energy but also exhibits excellent film-forming properties upon solution processing. We achieved highly efficient blue and white electrophosphorescent OLEDs through solution processing. In the part B, we have prepared efficient red OLEDs incorporating POAPF as the host material doped with the osmium phosphor Os(fptz)2(PPh2Me)2. POAPF, which possesses bipolar functionalities, can facilitate both hole and electron injection from the charge transport layers to provide a balanced charge flux within the emission layer. In addition, we fabricated a POAPF-based white-light OLED - containing red- [doped with Os(fptz)2(PPh2Me)2] and blue-emitting [doped with FIrpic] layers - that also exhibited satisfactory efficiencies. (2)Studies of multifunctional blue emitters containing triphenyl- phosphine oxide First, we have synthesized a highly efficient blue-light emitter, POAn, which comprises electron-deficient triphenylphosphine oxide side groups appended to the 9- and 10-positions of a 2-tert-butylanthracene core. In addition to serving as an electron-transporting blue-light-emitting material, POAn also facilitates electron injection from the Al cathode to itself. Consequently, simple double-layer devices incorporating POAn as the emitting, electron-transporting, and -injecting material produce bright deep-blue lights. Furthermore, in part B, based on the advantage of triphenylphosphine oxide-based emitter, a novel bipolar blue emitter, TPAPOAn, bearing hole-transporting arylamine groups and electron-transporting triphenylphosphine oxide moieties was synthesized and incorporated into an efficient single-layer device, revealing very promising performances comparable to those of multi-layer blue-emitting devices.
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Shih, Hung-Hsin, and 施宏欣. "Blue Phosphorescent Emitters and Hosts and Their Application in Organic Electroluminescent Devices." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/78214494881042659951.
Full textAbstract:
博士國立清華大學
化學系
95
Abstract We have presented the syntheses of more deep blue iridium complexes with using the 3-phenylpyrazole ligands and new third ligands to form the typical cyclometalated (C^N) chelation and typical anionic (N^N) chelation for iridium center, respectively. According to the third ligands (N^N), they can be divided into two series: One is 2-pyridylpyrazole with five-six member rings, the other is 1-imidazolylpyrazole with five-five member rings. Physical properties, including UV-vis absorption, emission spectra in CH2Cl2 or solid crystal at room temperature, and HOMO and LUMO energy levels of these blue phosphorescent materials were checked. Most of these compounds emit room-temperature blue light and the more deep blue emission was located around 438, 464 and 496 nm. When using sean111 as dopant, the device shows emission peaks at 454, 482 nm, maximum brightness of 4299 cd/m2, maximum external quantum efficiency of 1.2 % and good CIE coordinates of (0.14, 0.17). Heteroatom-center-arylsilane derivatives (BSi, BSiB, BSiCN and BSiPN) were synthesized as novel host materials for deep blue or greenish-blue phosphorescent dopants. These materials not only have good thermal stability (melting point and glass-transition temperature) but also high triplet-state energy level above 2.9 eV. The devices with FIrpic or (dfppy)2Ir(pytz) doped in them have high luminous efficiencies, including external quantum efficiency, current efficiency and power efficiency. The maximum external quantum efficiencies of BSi:FIrpic and BSiB:(dfppy)2Ir(pytz) devices were 9.6 % with the CIE coordinates of (0.14, 0.29) and 8.2 % with the CIE coordinates of (0.13, 0.21), respectively. Triarylaminotriptycene derivatives were conveniently prepared as host materials for RGB phosphorescent dopants. TCTP and TPTP exhibit excellent thermal stability and a high melting point, especially TCTP (Tg = 238 ℃, Tm = 378 ℃). Both of them have high triplet-state energy level (above 2.9 eV) improved the host–guest energy transfer to blue phosphorescent materials, but TPTP with lower triplet energy of 2.94 eV also can be used as a host for green and red phosphorescent materials. The blue devices of FIrpic and (dfppy)2Ir(pytz) show maximum external quantum efficiency of 10.1 % and 7.9 %, and the CIE coordinates of (0.14, 0.36) and (0.14, 0.22), respectively. The green device of TPTP:Ir(ppy)3 exhibits maximum external quantum efficiency of 11.5 % with the CIE coordinates of (0.23, 0.66). For the red device of TPTP:Ir(DBQ)2(acac) with the CIE coordinates of (0.62, 0.38), the maximum external quantum efficiency of 9.8 % is achieved. The two emission zones for white light device by employing FIrpic and Ir(DBQ)2(acac) have the maximum external quantum efficiency of 8.5 % and the CIE coordinates of (0.32, 0.33) at 8 V. We have demonstrated the white light-emitting devices with high brightness, and great external quantum efficiency and current efficiency from blue fluorescent (T1) or (T2) and green (Ir(ppy)3) and red (Ir(DBQ)2(acac) or Ir(MDQ)2(acac)) phosphorescent materials. The white EL spectra with the very stable three emission zones were contributed from three materials. In addition, they own very stable white CIE coordinates (0.34, 0.33) and (0.35, 0.37) and high CRI from 6 V to 15 V. The devices with the structure [NPB/CBP:Ir(DBQ)2(acac)/CBP: Ir(ppy)3/ T1 or T2 / Electron transporting materials show bright white light and good luminous efficiencies] . C60 doping in the thin hole transport materials as a hole-injection layer of an organic electroluminescent devices can improve the luminous efficiencies, including the maximum current efficiency and power efficiency at the same voltage and current density. When the concentrations of fullerene (C60) doped in NPB (7 nm) were varied between 25%-50%, the luminescence efficiencies also increased more than 30%. In addition, application in the general devices using C545T as a green dopant emitter in Alq has the same effects under similar conditions.
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LI, MING-CHIN, and 李明晉. "Wide-Bandgap P-Type Organic Emitters for High Efficiency Hybrid Silicon Heterojunction Photovoltaics." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/14164144137677218258.
Full textAbstract:
碩士國立清華大學
光電工程研究所
102
Silicon solar cells have the advantages of high efficiency and abundant resources on earth.And organic solar cells can be fabricated in low temperature,low-cost solution processes and also has roll-to-roll scalability.Combining the advantages of these two material systems,hybrid solar cells based on organic conjugated polymers and inorganic silicon is a promising alternative to simplify the fabrication processes and reduce the cost,while maintaining a high PCE. In this study,we introduce a co-solvent method to dope a wide band gap poly(9,9-dioctyfluorenyl-2,7-diyl) (PFO) fluorescent polymers with a very efficient electron acceptor tetrafluorotetracyanoquinodimethane(F4TCNQ).The p-doping layer was deposited onto and between 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane(TAPC)layer and SiNWs by the solution processing method in order to form a recombination layer and lower Fermi level of fluorescent polymers. Furthermore,Ultraviolet Photoelectron spectroscopy (UPS) and X-ray Photoemission spectroscopy (XPS) confirms that F4TCNQ is spatially graded doping via vertical phase separation in this p-type doping layer.The nearer to SiNWs,the more F4TCNQ is doped, which let p-type layers become more p-type. The power conversion efficiency reaches a record 13.6%, which is largely ascribed to the band bending between n-type silicon and p-doping layer interface.Consequently,holes can conduct to electrodes more easily by lowering energy barriers,which boost the open-circuit voltage and fill factor.
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Santos, Vasco Costa. "Organic Light Emitting Diodes: Photophysics of Thermally Activated Delayed Fluorescence Emitters and Device Characterization." Master's thesis, 2017. http://hdl.handle.net/10362/28218.
Full textAbstract:
In this thesis, the influence of bromine atoms on the mechanism responsible for the observation of thermally activated delayed fluorescence (TADF) is investigated. Heavy atoms, such as bromine, are well known to promote spin-orbit coupling (SOC), consequently facilitating the transition between singlet and triplet states by intersystem crossing (ISC). For that reason, organic heavy metal complexes are considered organic phosphors because their presence facilitates the radiative decay directly from the triplet state to the ground singlet state, giving origin to the observation of phosphorescence at room temperature. In TADF emitters triplet states are up-converted to high energy singlet excited state through thermally activated reverse intersystem crossing (RISC). Therefore, the presence of heavy atoms in the structure of TADF molecules poses an interesting question of knowing if whether it will assist RISC or if it will promote triplet decay directly to the ground state either through non-radiative processes or instead through phosphorescence.
This work gives clear evidence that bromine causes direct triplet state radiative decay to the ground state, causing an otherwise strong TADF emitter to show significant phosphorescence, even at room temperature.
A second objective of this thesis was to develop an experimental technique to directly probe the excited state dynamics and electroluminescence (EL) mechanism in working organic light emitting diodes (OLEDs), under device operation. This was accomplished by measuring the transient electroluminescence emission of TADF-based OLEDs on a newly assembled transient EL spectroscopy system developed within this project.
These studies show that charge trapping plays an important role in the operation of OLEDs, and largely dominates the EL generation. This is a direct consequence of the intrinsically disordered nature of organic emitters.
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Yen, Chia-Kuo, and 顏嘉國. "Doped Blue and Red Emitters of 9,10-di(2-naphthyl)anthracene in Organic Electroluminescent Device." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/19052896192992522799.
Full textAbstract:
碩士國立交通大學
應用化學系
90
If we can use one host emitter to excite different guest dopants to get R.G.B. color in organic light emitting devices (OLEDs), it will be a great advantage for full color application. Therefore in this thesis we studied the doping of blue and red guest molecules in a single blue host emitter to demonstrate the feasibility of this idea. Blue EL emission of 9,10-di(2-naphthyl)anthracene (ADN) based emitter in OLEDs is highly dependent upon its emitter thickness and attenuated by the microcavity effect of the emitter. By carefully tuning the emitter thickness of ADN and optimizing the doping concentration of 2,5,8,11-tetra(tert-butyl)perylene (TBP), one of the highest efficiencies ever reported for the anthracene based blue emitter at 5.1 cd/A with a CIE 1931 of (x=0.14; y=0.22) is achieved. The device of 4-(dicyanomethylene)-2-(t-butyl)-6-(1,1,7,7- tetramethyl-julolidyl-9-enyl)-4H-pyran (DCJTB) doped in ADN resulted in a bathochromic shift in CIE coordinates from red to orange. By choosing a dopant which absorbs in the infrared, such as 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7,8-9-enyl)]-4H-pyran (DCJTB-M). When DCJTB-M doped in ADN, we could achieve an efficiency of 1.52 cd/A with a CIE 1931 of (x=0.65; y=0.35) at 3.5 % doping concentration in the red region. The luminance efficiency is found to be essentially independent upon the drive current — a criterion which is important in the OLED module design and manufactuing.
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Huang, Sheng-Yang, and 黃勝揚. "Improving uniform dispersion of triplet emitters in multi-layer solution-processed organic light-emitting diodes." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/16213946315865161054.
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Chang, Kai-Wen, and 張凱文. "Investigation of organic light-emitting devices using resonant cavity structure and lasing properties of organic emitters with aggregation induced emission characteristics." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/ynn8d4.
Full textAbstract:
碩士國立中山大學
光電工程學系研究所
102
The first part of this thesis is concentrated on the color purity performance improvement of blue phosphorescent OLEDs. We integrated a high efficiency blue OLEDs with conducting DBR anodes, then optimized this device by modulating the thickness of organic films. With this configuration, we successfully improved the color purity of the blue-emitting device. The CIE 1931 color coordinate of the blue-emitting device with cavity structure was located at (x,y)= (0.14,0.14), and it of the device with no cavity structure was located at (x,y)=(0.14,0.35). In the second part of this thesis, we investigated two materials with aggregation induced emission (AIE) properties named as TPATPE and 2TPATPE. Due to their high steric hindrance, they can be well utilized in high efficiency OLEDs. First, we set the amplified spontaneous emission (ASE) experiments to measure their ASE thresholds, ASE spectrum, gain coefficients and loss coefficients. The results revealed that both TPATPE and 2TPATPE have good optical amplification properties with ASE thresholds about 2.7kW/cm2 and 4.9kW/cm2 and gain coefficients are 19cm -1 and 23cm-1, respectively. With a suitable resonant condition realized by 1-D DFB structure and the high gain materials, spectral narrowing and optical amplification properties were observed. Finally, two double-layered florescent OLEDs with high efficiencies were demonstrated. The EQE of TPATPE and 2TPATPE devices were 4.3% and 4.6%, respectively. This results indicated that both of these two materials are well suitable for display or lighting applications.
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DUNG, NGUYEN DUC, and 阮德勇. "Synthesis of graphene and its application for flexible and transparent conductors, organic contaminant absorbents, and electron field emitters." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/84328219292705864952.
Full textAbstract:
博士國立清華大學
材料科學工程學系
100
Graphene is defined as a flat monolayer of sp2-hybridized carbon atoms tightly packed into a two-dimensional (2D) honeycomb structure. This stringently 2D material exhibits a broad range of extraordinary properties, such as excellent electrical and thermal conductivities, and extremely high strength, which hold great promises in a variety of applications in micro/nanoelectronics, composites, and clean energy. Of special interests are the physicochemical properties of graphene materials strongly dependent on synthetic methods, resulting in diverse practical uses employed. This dissertation mainly aims to develop new approaches for production of graphene materials using wet chemistry as well as chemical vapor deposition (CVD) methods. Subsequently, the as-synthesized graphene materials are employed for applications as flexible and transparent conductors, a key component for removal of organic contaminants (including oils or organic solvents) from water, a supporting barrier for growth of carbon nanotubes (CNTs), and effective fillers for enhancing electron field emission performance of a vacuum filtered CNT film. Generally, exfoliation of graphite into graphene sheets by wet chemistry approaches require intercalating chemicals into interspaces of graphite layers followed by harsh oxidation and reduction or selecting a solvent with surface tension close to that of graphite. In our approach, we prepared ethanol soluble fewlayer graphene nanosheets (FLGs) without adopting the common receipts, thus avoided using toxic oxidizing/reducing agents or poisonous solvents. Atomic force microscopy and high-resolution transmission electron microscopy studies reveal that FLGs have average thicknesses in the range of 2.6–2.8 nm, corresponding to 8–9 layers. A graphene/nafion composite film has a sheet resistance of 9.70 kΩsq-1 at the transmittance of 74.5% (at 550 nm) while the nafion film on polyethylene II terephthalate has a sheet resistance of 128 kΩsq-1 at transmittance of 90.0%. For the cycling/bending test, almost no change in resistance was exhibited when the film was bent at an angle up to 1400, and no obvious deviation in resistance could be found after 100 bending cycles. In addition, a FLGs/poly(3,4- ethylenedioxythiophene): poly(styrenesulfonate) composite layer was demonstrated as the effective hole transporting layer to improve the hole transporting ability in an organic photovoltaic device, with which the power conversion efficiency was enhanced from 3.10% to 3.70%. We further investigated the hydrophobic properties of the ethanol soluble FLG material and its combination with a type of commercial sponge. The FLG films possess strong hydrophobic properties besides their opto/mechano-electrical properties aforementioned. By coating an appropriate amount of FLGs on the sponge skeletons with polydimethylsiloxane (PDMS) binder, superhydrophobic (water contact angle of ~1620) and superoleophilic (oil contact angle of ~00) graphene-based sponges were obtained. The as-fabricated graphene-based sponges perform as an efficient absorbent for a broad range of oils and organic solvents with high selectivity, good recyclability, and excellent absorption capacities up to 165 times their own weight. In addition to wet chemistry method, we also developed a CVD method to grow graphene and integrate thin CNT networks on the surface of the graphene film using the same CVD system. The thickness of graphene and the CNT density on graphene surface can be controlled properly. Graphene films are demonstrated as an effective supporting barrier for preventing poisoning of iron nanoparticles which catalyze the growth of CNTs on copper substrates. Based on this method, the opto-electronic and field emission properties of the graphene integrated with CNTs can be remarkably tailored. A graphene film exhibits a sheet resistance of III 2.15 kΩsq-1 with a transmittance of 85.6% (at 550 nm) while a CNT–graphene hybrid film shows an improved sheet resistance of 420 Ωsq-1 with an optical transmittance of 72.9%. Moreover, CNT–graphene films reveal as effective electron field emitters with low turn-on and threshold electric fields of 2.9 and 3.3 Vμm-1, respectively. In order to combine the merits of the two-dimensional graphene and onedimensional CNT nanocarbon materials, many efforts have recently been made to obtain graphene-CNT hybrid materials or composites. Most studies on these hybrid materials focused on optoelectronic and electrical properties. Several attempts to create ohmic contact between CVD grown graphene and CNTs to enhance the field emission properties have been investigated. However, no studies utilizing reduced graphene oxide (RGO) nanosheets as the conductive fillers as well as the secondary emitters for enhancing field emission performance of CNT film have been reported to date. Herein, the composite films composing of CNTs and chemically reduced graphene nanosheets were fabricated using the vacuum filtration method. Compared to other processing methods such as chemical vapor deposition, electrophoresis, or screen-printing, this method is more beneficial for fabrication of low-cost field emitters with density controllable and additive avoidable. The composite films with different weight ratios between CNTs and graphene oxide (GO) are prepared by varying the volumes of CNTs and GO dispersions. The results show that the composite film with GO:CNT weight ratio of 1:3 after hydrazine treatment reveals the best field emission performance with low turn on and threshold fields of 2.82 and 2.98 V/μm, respectively.
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Shen, Mei. "The electrogenerated chemiluminescence of novel organic donor-acceptor emitters as well as study heterogeneous electron transfer kinetics using scanning electrochemical microscopy." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-08-3838.
Full textAbstract:
New modalities and novel emitters were investigated for the production of electrogenerated chemiluminescence (ECL). In annihilation ECL, a light-emitting excited state is formed upon reaction of two electrochemically generated species, typically a radical anion and a radical cation. Donor-acceptor (DA) molecules provide a means of generating these two reactive species within the same molecule but where the oxidized and reduced centers are separated; furthermore, they allow one to explore the ECL properties of multiply charged radical ions. Three new efficient ECL-emitting donor-acceptor molecules were investigated.
The effects of conjugation in the electrochemistry of diphenylaminospirobifluorenylfumaronitrile (FPhSPFN), which has the structure of D-X-A-A-X-D, where X is a linker, as well as the effects of the stability of its (multiply charged) radical ions on its red ECL emission (λmax= 708 nm) were studied; the molecule
shows solvatochromism and different emission yields on both photoluminescence and ECL in benzene:acetonitrle mixtures. The possibility of generating ECL through multiply charged radical ions was further tested with the very efficient 1b emitter (4,7-bis(4-(4-sec-butoxyphenyl)-5-(3,5-di(1-naphthyl)phenyl)thiophen-2-yl)-2,1,3-benzothiadiazole). Two reversible oxidations and one reduction were observed. The more sluggish reduction is proposed to be a consequence of a long distance electron transfer to the buried acceptor center; further confirmation of this effect was pursued by application of the scanning electrochemical microscope (SECM) to model systems. 1b emits intense ECL with λmax= 635 nm and with an efficiency 330% of the ECL standard 9, 10-diphenylanthracene and similar intensity to the red emitting standard tris(2,2′-bipyridine)ruthenium(II) perchlorate (Rubpy). The generation of asymmetric chronoamperometric ECL pulses upon generation of radical anion-radical dication annihilation events was explained by the use of digital simulation, and proven to be a consequence of asymmetry in the amount of generated charges rather than instability of the electrogenerated species. ECL was also produced from a film of a red fluorophore 1a (4,7-bis(4-(n-hexyl)-5-(3,5-di(1-naphthyl)phenyl)thiophen-2-yl)-2,1,3-benzothiadiazole) with a coreactant in PBS buffer solution.
The electrochemical synthesis of carbon quantum Dots (C QDs) in inert atmosphere was explored using highly oriented pyrolytic graphite as the starting material, for its later use in the production of ECL in the radical annihilation mode. FT-IR (ATR), mass spectrometry (desorption chemical ionization), Raman and TEM analysis were used to characterize the C QDs.text
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Tseng, Po-Chen, and 曾柏宸. "Efficiency Enhancement of Organic Light-emitting Diodes by Exciplex Sensitized Triplet-triplet Annihilation for Blue Emission and Different Thermally Activated Delayed Fluorescence Emitters." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/ez6y2p.
Full textAbstract:
碩士國立臺灣大學
光電工程學研究所
105
There are two topics in this thesis. The first one is efficiency enhancement of exciplex sensitized triplet-triplet annihilation (ESTTA) blue organic light emitting diodes (OLEDs). The second one is red, green, blue OLEDs with 9,9''-(2-(1-Phenyl-1H-benzo[d]imidazol-2-yl)-1,3-phenylene)bis(9H-carbazole) (o-DiCbzBz) as the universal host material for thermally activated delayed fluorescence (TADF) emitters. The exciplex was formed at interface of electron donor and acceptor organic materials, then triplet energy transfer (TET) to TTA blue emitter to generate upconversion blue emission, which was called exciplex sensitized triplet-triplet annihilation (ESTTA) process. With insertion of triplet assisting and singlet blocking (TASB) layer and incorporation of fluorescent dopant, the blue ESTTA-OLED exhibited maximum external quantum efficiency (EQE) of 5.1% including blue emission EQE of 3.8%. In addition, transient electroluminescence (TrEL) was used to examine the origin of blue emission. In turn-off luminance response, only slow decay was observed implying blue emission all came from exciplex energy transfer to emitter to facilitate TTA upconversion emission, called ESTTA process. o-DiCbzBz was used as host material, doped with metal-free red, green, and blue TADF dopants to achieve high efficiency OLEDs in order to simplify manufacturing process and reduce production cost. After the optimization of the device structure, maximum current efficiency of 11.3 cd/A, 91.8 cd/A, and 31.4 cd/A, maximum power efficiency of 11.9 lm/W, 91.9 lm/W, and 28.2 lm/W, and maximum EQE of 9.0%, 26.2%, and 11.5% were obtained for blue, green, and red TADF-OLEDs, respectively, showing the feasibility of o-DiCbzBz as the universal host for RGB high efficiency TADF-OLEDs.
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Chu, Miao-Tsai, and 朱妙采. "Development and application of composite emitter for organic light-emitting devices." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/34916891000151798193.
Full textAbstract:
碩士國立交通大學
平面顯示技術碩士學位學程
98
In this thesis, we introduce a concept of “composite emitter” for applying on organic light-emitting devices (OLEDs). The composite emitter is doping a carrier-transporting material into conventional host-guest emitter for promoting the transport of carriers from carrier-transporting layer into emitter to increase the efficiency and decrease the driving voltage of OLED. Especially, the composite emitter can apply to blue phosphorescent OLED which need to use a wide-bandgap host material; in additional to we also apply this concept to the green phosphorescent OLED, Green/Red yellow phosphorescent OLED and tandem white OLED. (1) Blue phosphorescent OLED A blue phosphorescent OLED with a current efficiency of 26.5 cd/A, a power efficiency of 19.9 lm/W, a driving voltage of 4.2V and CIEx,y of (0.17, 0.36) at a brightness of 1000 cd/m2 can be achieved by composite emitter which was composed a host material of PPT and a carrier-transporting material of TCTA. Under the composite emitter, the blue phosphorescent OLED was improved by a factor of 2.1 comparing to that of using conventional host-guest emitter. (2) Green phosphorescent OLED A green phosphorescent OLED with a current efficiency of 52.7 cd/A, a power efficiency of 47.7 lm/W, a driving voltage of 3.4V and CIEx,y of (0.33, 0.61) at a brightness of 1000 cd/m2 can be achieved by composite emitter which was composed a host material of CBP and a carrier-transporting material of TCTA. Under the composite emitter, the green phosphorescent OLED was improved by a factor of 1.2 comparing to that of using conventional host-guest emitter. (3) Green/Red yellow phosphorescent OLED A yellow phosphorescent OLED which was co-doping green and red phosphorescent dopant into composite emitter at the same time with a current efficiency of 44.1 cd/A, a power efficiency of 40.7 lm/W, a driving voltage of 3.4V and CIEx,y of (0.45, 0.52) at a brightness of 1000 cd/m2 can be achieved by composite emitter. Under the composite emitter, the yellow phosphorescent OLED was improved by a factor of 1.4 comparing to that of using conventional host-guest emitter. (4) Tandem white OLED Finally, under the concept of composite emitter, applying a blue phosphorescent OLED and a green/red yellow phosphorescent OLED to fabricate a tandem white OLED through a connecting layer which was constructed by n-doped/p-doped layers. A tandem white OLED with a current efficiency of 70.1 cd/A, a power efficiency of 27.5 lm/W, a driving voltage of 8V, CIEx,y of (0.33, 0.48) and a color rendering index (CRI) of 72 can be achieved. In order to improve the CRI for attaining a practical value of 80, using a blue fluorescent OLED with saturated color to instead of blue phosphorescent OLED. The tandem white OLED with a current efficiency of 44.2 cd/A, a power efficiency of 18.8 lm/W, a driving voltage of 7.4V, CIEx,y of (0.39, 0.45) and a color rendering index (CRI) of 84 can be achieved.
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Ting, Lee Meng, and 李孟庭. "Development and Application of Blue Guest-Host Emitter for Organic Electroluminesncet Devices." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/00937054042688579793.
Full textAbstract:
博士國立交通大學
應用化學系所
94
In this thesis, development of blue-doped organic light-emitting device (OLED) is the major subject, which has been applied in the fabrication of white OLED as well as improvement of the device stability. The study is divided into four sub topics as following: (1) Light-blue OLED: A highly efficient and stable blue OLED based on a distyrylamine (DSA) dopant, p-bis(p-N,N-diphenyl-aminostyryl)benzene (DSA-Ph) in a morphologically stable blue host material, 2-methyl-9,10-di(2-naphthyl)- anthracene (MADN) was demonstrated, which achieved an EL efficiency of 9.7 cd/A and 5.5 lm/W at 20 mA/cm2 and 5.7 V with a Commission Internationale d’Eclairage coordinates (CIEx,y) of [0.16, 0.32]. The light blue-doped device achieved a half-decay lifetime (t1/2) of 46 000 h at an initial brightness of 100 cd/m2. (2) Deep-blue OLED: New deep blue dopants based on unsymmetrical mono(styryl)amine derivatives were designed and synthesized, which provided us with the basic structure for color tuning within the spectral region between 416~450 nm. When doped in MADN host and incorporated a composite hole transport layer (c-HTL) as OLED, the device achieved an EL efficiency of 5.4 cd/A with a CIEx,y of [0.14, 0.13] and an external quantum efficiency of 5.1% at 20 mA/cm2. The deep blue-doped device achieved a half-decay lifetime (t1/2) of 10 000 h at an initial brightness of 100 cd/m2. (3) White OLED: When incorporating the 2,8-di(t-butyl)-5,11-di[4-(t-butyl)-phenyl]- 6,12-diphenylnaphthacene (TBRb) doped NPB as the yellow emitter into the two-element white OLED based on light-blue emitter (DSA-Ph@MADN), the device achieved an EL efficiency of 9.8 cd/A and 3.9 lm/W at 20 mA/cm2 and 7.9 V with a CIEx,y of [0.31, 0.40]. The NTSC ratio passed through the color filter is 58.7%. In order to improve the NTSC ratio, three-element white OLED was fabricated, which consisted of green, red and deep-blue emitter (2BpSA-Biph@��-MADN). The device achieved an EL efficiency of 5.2 cd/A and 3.0 lm/W at 20 mA/cm2 and 6.4 V with a CIEx,y of [0.31, 0.33]. The NTSC ratio was improved by 10% to 68.1%. (4) Device stability: The stability of C-545T doped green OLED has been improved by doping DSA-Ph in hole-transporting, electron-transporting or emitter layer. Compared with the undoped device, the stability increased by a factor of 1.3、1.8 or 2.6, respectively and the half-decay lifetime (t1/2) of 16 000 h at an initial brightness of 100 cd/m2 was achieved.
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Yang, Chi-Yu, and 楊基佑. "Organic and Hybrid Light Emission Devices Utilizing Delay Fluorescent and Quantum-Dot Emitter." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/4ge95k.
Full textAbstract:
碩士國立交通大學
光電工程研究所
104
In this thesis, We studied the device engineering and photophysical properties of delay fluorescent materials, quantum dots and inorganic halide perovskite light-emitting devices. In the introduction, We briefly reviewed the applications and current development of organic light-emitting diodes (OLEDs) for solid-state lighting and display. In the second chapter, We reviewed the history of OLEDs, and their operating principles and measurement methodology. In the third chapter, We investigated two novel excimer-formation materials, and studied the characteristics of the excimer emission. Careful transient photophysical measurements revealed the exciton up-conversion from triplet states to singlet states. The excimer-base OLEDs were fabricated and optimized by judicious selection of the electron transport materials. The device showed an external quantum efficiency (EQE) up to 6.5%, which is higher than the theoretical efficiency of the conventional fluorescent OLEDs. In the fourth chapter, We measured the photoluminescence (PL) quantum yield of the quantum dots (QDs). And fabricated quantum dot light-emitting devices by blending QDs with Tris(4-carbazoyl-9-ylphenyl)amine (TCTA) as an emission layer. Vertical phase separation between QDs and TCTA was observed .The device with lowest QDs concentration possessed the highest EQE of 0.62%. In the fifth chapter, We studied a series of thermally activated delayed fluorescence materials, of which the emission colors range from green to deep-blue. Large bandgap materials were selected as their host materials. We measured the temperature-dependent transient PL to analyze the delay fluorescence characteristics of these compounds. The efficient deep-blue OLEDs with International Commission on Illumination (CIE) coordinates of (0.18, 0.14) and a EQE up to 6.5% were demonstrated. In chapter six, Cesium Lead halide Perovskite films were deposited by dual source thermal evaporation. We further studied the charge transport and emission characteristics of Cesium Lead halide Perovskites. Finally, We demonstrated organic-inorganic hybrid light-emitting devices.
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Chen, Hsi-An, and 陳璽安. "Study of Composite-emitter with Graded-connecting layer in Organic Light-emitting Diodes." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/47999531876264204080.
Full textAbstract:
碩士國立交通大學
顯示科技研究所
100
We introduced novel fabrication method and a composite emitter structure with graded-connecting layer (CG-EML) for OLED by utilizing a conventional R&D thermal-evaporation coater. Hole-transporting NPB/electron-transporting BAlq doped with green fluorescence C545T was selected as the composite system of mixed hosts and guest materials of study to demonstrate the advantages and attributes of the CG-EML OLED. Compared with conventional bi-layer (B-EML), composite-emission layer (C-EML) and graded-emission layer (G-EML) devices, the current efficiency and the lifetime of CG-EML device were superior, especially in suppressing concentration quenching as was found in G-EML device. Lifetime of CG-EML OLED was also 13.6 times better than that of B-EML by the formation of a fuzzy interface that promotes better the charge balance in the doped emitter.
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林佑星. "Highly Efficient Yellow Organic Light Emitting Diode with a Novel Iridium Complex Emitter." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/65823334264162118731.
Full textAbstract:
碩士國立清華大學
材料科學工程學系
101
Yellow emission is crucial in RGBY display technology and in fabricating physiologically-friendly low color temperature lighting source. Emitters with both wet- and dry-process feasibility are highly desirable to fabricate, respectively, high quality devices via vapor deposition and cost effective large area-size devices via roll-to-roll fabrication. We demonstrate in this report high-efficiency organic light-emitting diodes with a novel wet- and dry-process feasible yellow emitting iridium complex, bis[5-methyl-7-fluoro-5H- benzo(c)(1,5) naphthyridin- 6-one]iridium (picolinate). By spin coating, the device shows, at 1,000 cd /m2 for example, an external quantum efficiency (EQE) of 18.5% with an efficacy of 52.3 lm/W, the highest among all reported yellow devices via wet-process, while using vapor deposition, the EQE is 22.6% with a 75.1 lm/W efficacy, the highest among all dry-processed counterparts. The high efficiency may be attributed to the replacement of the hydrogen atom with a fluorine atom on a 2-substitutional site in the emitter to prevent dense molecular packing caused self-quenching and reduce radiationless deactivation rate, leading to a high quantum yield (71%).
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Lee, Jhen-De, and 李振德. "High-Efficiency Organic Light Emitting Diodes Based on a Thermally Activated Delayed Fluorescence Emitter." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/a3h2v6.
Full textAbstract:
碩士國立臺灣海洋大學
光電科學研究所
103
In this thesis, we study about the thermally activated delayed fluorescence (TADF) light emitting devices. TADF enables triplet excitons to up-convert to emissive singlet excitons through effective reverse intersystem crossing (RISC) to reach 100 % exciton harvesting ability. As a result, TADF has evolved to be the most feasible EL mechanism for the next-generation OLED in replace of the high-cost PhOLEDs. In first part, we reported two TADF host materials (pCNCz and pCNCz-PH) to evaluated the performance of OLEDs containing the dopants 4CzIPN (green emission), 4CzTPN (yellow emission) and 4CzTPN-Ph (orange emission) as emitters. In order to estimate the theoretical enhancement of EL efficiency, we setup a time-resolved spectrometer system and absolute photoluminescence quantum yield measurement system to measure transient PL and PL Q.Y. By employing pCNCz-PH : 4CzIPN as an emitter, we have achieved high-performance TADF-based green OLEDs, exhibiting EQE as high as 15.4 %. The yellow and orange OLEDs had EQE of 9.1 % and 8.2 %, respectively, which are also higher than those of conventional fluorescence-based OLEDs. In the second part, we study of NPCz and NPDa with different linking topology as host materials to evaluate the performance of OLEDs. The different linking-topology and effective π-conjugation length comprehensively tune the energy levels and their bipolar transport abilities allowing to the unexpected high device performance. Notably, p-NPCz, employed as a TADF host doped with 4CzIPN, exhibited the remarkable maxima EQE of 18.5 % (60.8 cd/A and 53.8 lm/W). At rather high current densities, a high EQE of 17.7 % was obtained at 1000 cd/m2. From transient PL and PL Q.Y. analysis, the theoretical maximum EQE is thus estimated to be 18.5 % (assuming a light outcoupling efficiency of 20 %), which are close to experimental data. Therefore, near-complete carrier recombination and exciton confinement in the EML were realized in the device.
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WANG, YI-AN, and 王亦安. "Characterization of Air Pollutants Emitted from Burning Organic Sludge Induced Fuels." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/vt68w8.
Full textAbstract:
碩士萬能科技大學
環境工程研究所
106
In this study, both the theoretical prediction method and the experimental method were applied to assess the concentration variationof air pollutants in combustion exhausted gas emitted from burning sludge induced fuel under batch and non-control combustion conditions. The theoretical method is based on the molecular collision frequency theory and the general combustion theory for air-to- fuel ratio equal or greater than 1.0. In general, the predicted concentrations and their variation trends of CO、NO、CH4、NH3、H2S seem reasonal. Hence, the prediction method established in this study is acceptable. Study results show that under air-to-fuel ratio less 1.0, the lower the ratio, the higher the concentrations of air pollutants such as CO, NO, VOCs, PM10 theoretically predicted. Although the experimental method cannot give comparable data due to limitation of monitoring range, it did provide similar results. From waste gas monitoring data, we confirmed these findings: (1) Lower CO and VOCs concentrations were monitored for samples added with 10% carbon black than without adding that material; (2) SO2 was completely removed from the waste gas stream by adding 10% lime to tested samples; (3) Lower CO and higher NOx and VOCs concentrations were monitored after samples added with 10% coffee drink residue. However, other appropriate control methods including keeping air-to-fuel ratio may help a cleaner emission.
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Li, Chieh-Ju, and 李倢如. "Highly Efficient Green Organic Light Emitting Diode with a Novel Solution Processable Iridium Complex Emitter." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/15153884505259559726.
Full textAbstract:
碩士國立清華大學
材料科學工程學系
101
Green light is both the major component for the fabrication of multi-band composing white light and the key color of the typical RGB full-color technology. Moreover, it is also the most critical composition for the highly efficient white light since luminous sensitivity of human eyes is the highest with green light. Therefore, innovatively developing a high-efficiency green device is quite crucial. For the organic light emitting diodes (OLEDs), on the other hand, solution process is a promising technology to realize roll-to-roll production and to achieve low-cost probability. We hence study in this thesis the fabrication of a highly efficient green OLED device with a solution-processable emissive layer. We demonstrate a high-efficiency green OLED with a solution-processed emissive layer composing a novel green light emitting iridium complex, bis[5-methyl-8-trifluoromethyl-5H-benzo(c)(1,5) aphthyridin-6-one]iridium (pyrazinecarboxylate). By coupling with a proper host, the green device shows at 1,000 cd m-2 an external quantum efficiency of 23.8%, current efficiency of 95.6 cd A-1, and efficacy of 60.8 lm W-1, the highest among all reported solution-processed OLEDs. The high efficiency may be attributed to the host possessing a zero electron injection barrier, resulting in a more balanced carrier-injection. Besides, the paired host and guest energy-levels allow excitons to generate on the guest predominantly at low voltage, but with increasing excitons generating on the host with the increasing voltage.
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Wu, Hsin-Ching, and 吳信慶. "Characteristics of organic indicators and particle number concentrations emitted from incense burning." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/7qz8m7.
Full textAbstract:
碩士嘉南藥理科技大學
環境工程與科學系暨研究所
99
Incense burning is an important ritual to pray to worship the gods or ancestors for people in Asia. This study focused on the emission properties of selected different types and kinds of incense burning. The incenses were divided into four incenses with stick, the other four incenses without stick. Additionally, three kinds of Thailand incenses were also studied. Totally, there are 11 kinds of incense to discuss. Particles released from different burning incense ranged of 17.3-80.2 mg-particle g-1-incense. Organic carbon compounds which accounted for all mass of burning smoke particles 31.9-81.6%, with carboxylic acids, anhydrosugars and sugar alcohols, all accounted for 1.56-4.68% of PM mass of burning smoke particles. Inorganic salts accounted for 1.97-9.54% of particle mass. Chloride, sodium and potassium are the most dominant species in inorganic salts, indicating chloride and potassium is the primary aerosol of biomass burning. Carboxylic acid contributed 1.09-3.64% of particle mass of incense burning. Acetic acid is the most abundant component of the carboxylic acids. Mass ratio of acetic acid/formic acid (A/F ratio) ranged from 1.93-5.38 for different burning incense. Anhydrosugars and sugar alcohols contributed 0.20-1.12% and 0.12-1.35%, respectively, of particle mass of incense burning. This study found that levoglucosan, mannosan, galactosan, arabitol, xylitol, galactose, did not exist in the unburned incense powder, meanwhile these species were significant abundant in burning particles, indicating the potential organic biomarkers for incense burning smoke. Mass ratios of levoglucosan/xylitol ratio in PM ranged between 6.4-15.4 released from burning incenses with stick. Meanwhile, the ratios of levoglucosan/xylitol in PM were between 11.0-25.6 released from buring incenses without stick. Additionally, there were mass ratios of levoglucosan/mannosan of 0.36-2.65 in PM emitted from different incenses burning. Both of levoglucosan/xylitol and levoglucosan/mannosan could be used as organic markers for biomass burning. two kinds of mass ratios can be used as organic markers of incense burning. Particle size distribution released from incense burning ranged mainly between 100~400 nm, accounting for 88.4-89.2% of total particle number concentrations. Their number medium aerodynamic diameters peaked in the 187-195 nm, indicating the different incenses have the similar combustion performance.
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Makarow, Ramona Irina Gloria Fanny. "Identification of the specific volatile organic compounds emitted by Anoplophora glabripennis (Moschulsky)." Thesis, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-137F-8.
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Liu, Po Hung, and 劉柏宏. "The particulate and its soluble organic fraction emitted from a heavy diesel vehicle." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/24320076205796531538.
Full textAbstract:
碩士嘉南藥理大學
環境工程與科學系
102
This study is to understand the emission differences of total particulate pollutant (TSP) before and after improving the exhausting pollution of the diesel vehicles and the ratio of the soluble organic fraction (SOF) and insoluble organic fraction (IOF) in the particulate pollutant and the differences in the four different engine operating condition and the situation of the gaseous pollutants. In the differences of emission, the exhausting rate before improving were 54.9%, 46.7%, 63.9%, and 11.1%; after improving, it was declined to 11.3%, 8.0%, 25.3%, and 0.3%. The smoke were decreased for over 60%. The average emission for the unit mileage were 197.8 g/Km and 47.1 g/Km, which had a 4.2 times of differences. In the sample of the particulate matter which did not comply with the regulation, the SOF rate was higher than IOF in the 100% point. However, in the 60% and 40% points, SOF rate was lower than IOF. In the idle condition, they were about the same. However, after improving the exhausting condition, SOF rate was prominently lower than IOF in the 100% test point. In the 60% and 40% test points, SOF rate was higher than IOF. The rate before and after the improvements reversed. Under the condition of 100% point and idle engine operation, although the particulate pollutant and the exhausting smoke reached to comply with the regulation, the gaseous pollutant CO and HC concentrations went higher, which was not actually improved. Also, according to the figure acquired from the study, the TSP emission and exhausting smoke before and after the improvement and the concentration of CO and HC were related to the height.
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Chen, Chi-Wei, and 陳奇蔚. "Study on Pollution Control Cost of Volatile Organic Compounds Emitted from Semiconductor Industry." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/22097368367273926437.
Full textAbstract:
碩士元智大學
機械工程學系
95
In order to conform to the environmental protection regulations, most of the semiconductor industry set up the pollution control units to eliminate the acidic and alkali exhausts, as well as volatile organic compounds (VOCs). However, the capital cost of the zeolite rotary adsorber systems is generally over ten million dollars, and it is also expensive for that of activated carbon adsorber devices. Although the wet scrubbers are inexpensive compared to the above two equipments, much more units are required and the total maintenance costs are higher. Therefore, this study is to explore the pollution control cost frame of VOCs emitted from the semiconductor industry, determine the key factors affecting the cost, derive the cost functions, and define the domain of the model. According to the results of correlation analysis, the main factors for zeolite rotary adsorber systems affecting the pollution control cost of VOCs are the pollution quantity and the electric charge. For activated carbon adsorber units, the major factors are the cost of activated carbon consumption, the electric charge, the pollution quantity, and the removal efficiency. After regression analysis, the parameters retained in the pollution control cost function of VOCs for zeolite rotary adsorber system are the pollution quantity, the cost of natural gas utilization, and the capital cost. This model has an explanation power of 68.8 %. In addition, the cost function of the activated carbon adsorber units includes the cost of activated carbon consumption, the electric charge, the capital cost, the pollution quantity, the term of validity, and the remove efficiency. This model has an explanation power of 92.8 %. As a result, these two models should be powerful to predict and determine the pollution control cost of VOCs under the defined domain.
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Hsieh, Yao-Ching, and 謝曜璟. "Achieving at very high luminance an extraordinarily efficient red organic light emitting diode with a novel fluorescent emitter." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/01790561705777895976.
Full textAbstract:
碩士國立清華大學
材料科學工程學系
100
We demonstrate at a very high luminance an extraordinary high-efficiency red fluorescent organic light emitting diode (OLED) by using a novel red emitter, 3-(N,N-diphenylamino)-7-di(cyanoyl)-5,5 -spirofluorenyl-5H-dibenzo [a,d] cycloheptene (N-STIF-DCN).The device exhibits, at 33,000 cd/m2 for example, a major peak at 612 nm with an external quantum efficiency of 8.5% with 13.6 cd/A and 3.0 lm/W, The high efficiency oberserved at the extremely high brightness may be attributed to four efficiency-effective architectural factors of the device designed as well as the unique electro-luminance effective material factor of the red dye synthesized. The five efficiency-effective architectural factors are low injection barrier, balanced carrier injection, effective carrier confinement, maximum excitons generation in both host and guest, and effective host-to-guest energy transfer.
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Yang, Yu-Min, and 楊喻閔. "High-Efficiency Wet- and Dry-Processed Green Organic Light Emitting Diodes with a Novel Iridium Complex Based Emitter." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/03431687167127634632.
Full textAbstract:
碩士國立清華大學
材料科學工程學系
101
High efficiency green emission is crucial to the designs of energy-saving display and lighting. Efficient electroluminescent green emitters with both wet- and dry-process feasibility is highly desirable in order to realize, respectively, cost-effective large roll-to-roll manufacturing and high performance products. We demonstrate in this study high efficiency phosphorescent green organic light-emitting diodes with a novel iridium complex, bis[5-methyl-8-trifluoromethyl-5H-benzo(c)(1,5)naphthyridin- 6-one] iridium (acetyl acetonate), possessing both wet- and dry-process feasibility. The emitter exhibits a short excited-state lifetime, 1.25 μs, and a high quantum yield, 69%, due to the efficient intersystem crossing of the ground-state to the excited-state. Using 4,4’-bis(carbazol-9-yl) biphenyl as host for example, the device shows at 1,000 cd m-2 an external quantum efficiency (EQE) of 21%, current efficiency of 77 cd A-1 and power efficiency of 64 lm W-1 via vapor deposition, while 26% EQE, current efficiency of 77 cd A-1 and 69 lm W-1 by spin-coating, the highest among all reported wet-processed green organic light-emitting diodes. Besides the electroluminescence effective emitter, the high device efficiency may also be attributed to the employed device architecture enabling therein an electron trap to facilitate the injection of this minor carrier against that of hole, leading to a balanced carrier-injection, and hence a high carrier recombination and in turn a high device efficiency.
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Hong, Gung-Hwa, and 洪廣華. "A Study of the Characteristics of Volatile Organic Compounds Emitted from Industrial Waste Recovery Processes." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/v9jv2g.
Full textAbstract:
碩士國立交通大學
工學院永續環境科技學程
101
Recently, Taiwan's high technology industry is progressing day by day which increases industrial waste from 11,038,617.30 to 17,730,806 ton per year. Now, there are 167 Public and Private Waste Clearance and Disposal companies in Taiwan which can dispose 73444.7 ton waste per month. Transport and recovery of hazardous industrial waste increase risk of damaging natural environment. Thus, the study of the characteristics of volatile organic compounds emitted from industrial waste recovery processes is important. This study is to discuss the correlation between Total Volatile Organic Compounds(TVOC) and Total Hydrocarbon (THC) under the following three physicochemical treatment processes: waste fluid recovery, incineration, and heat treatment in Taoyuan County. Direct Monitoring was conducted using a Photoionization Detectors (PIDs) and a Flame Ionization Detectors (FIDs). Canisters were further used collect air samples in work environments for further analysis to understand the characteristics of VOCs at three different waste treatment processes The monitoring results of plant A, B, and C showed the average concentration of TVOC was 2.078ppm, 2.056ppm, 0.334ppm,and the average concentration of THC as 3.18ppm, 3.37ppm, 5.36ppm, respectively. The qualitative and quantitative results of VOCs indicated TVOC concentration was 3881.1ppbv, 1543.0ppbv, and 78.5ppbv, respectively. The total BETX environmental exposure level was estimated to be 13.711 mg/d at the waste fluid recovery process, and 4.088 mg/d at the incineration process.