1,720,965 research outputs found
Sustainable Materials and Process Techniques for Engineering Solution-Based Organic Light-Emitting Devices
Get PDFAdvances in organic light emitting devices are crucial for the development of the display and solid state lighting (SSL) technologies. This dissertation is organized and pursued in three main projects to meet some problems in the field.
Printing technologies can be the key to next-generation affordable, flexible, large area displays and lighting elements by eliminating vacuum processing. In the first part of the thesis, the conventional gravure printing technique was adapted for the processing of emissive layers in the small molecule based organic light-emitting diodes (OLEDs) and light-emitting electrochemical cells (LECs). The homogeneous printed layers were granted by either modifying the functional ink properties or altering the printing process parameters. Different functional inks comprising the small molecule as an emissive material were formulated by adjusting viscosity, surface tension, and solvent drying kinetics of the inks. As for the process parameters, the gravure cell parameters such as line screen and tone values were altered to control the overall transfer volume of the ink and the thickness of the printed layers. In both cases, the electrically inert polymers were used as host materials to modify the rheological behavior of the ink while suppressing the aggregation of the small molecule in a solid film. The thin film characteristics of printed layers were analyzed in both qualitative and quantitative ways. The printed films were successfully implemented in the active layer of efficient small molecule based electroluminescent devices on flexible plastic foil. The optical and electrical device performance were considered as well as the effect of the printing process in comparison to spin-coated pristine small molecule based reference devices. The quality and performance of the printed emissive layers in both device type showed that the gravure printing method can be an alternative solution for wet-processing roll-to-roll (R2R) manufacturing in the future.
White light-emitting diodes draw particular attention in the field, due to their potential application as the backlight in displays or as energy efficient luminaires for SSL. Even though polymer OLEDs are well-suited for wet-based continues R2R fabrication, evaporation of low work function cathodes and therewith encapsulation remain as major obstacles. In the second part of the work, a novel hybrid device architecture was suggested for the color-tuning and white light emission in polymer light-emitting diodes. The single component polymer LEC layer performed as the electron injection layer as well as the second emissive layer on top of a conventional polymer OLED stack. The hybrid structure maintained a sufficient charge carrier injection from an air-stable cathode, due to the unique operation principles of LECs. As a proof of charge transport at the intersection of two emissive layers, dual color emission was simultaneously observed in a bilayer device configuration. A color-tuning in emission was obtained by changing the thickness of the LEC layer. The emission of hybrid devices was shifted from yellow to white light emission region of the CIE color chromaticity diagram, resulting in OLEDs with the high color temperature values. The results demonstrated that this approach showed a promising potential to achieve color-tuning and white light emission from solution processed OLEDs bearing air-stable cathodes.
Sustainable bioelectronics is an emerging technology which to replace conventional electronics with disposable counterparts in the future. Thus, bioinspired and bioderived materials usage in organic electroluminescent devices gained much attention in the last years. In the last part of the thesis, we investigated biodegradable natural and naturally derived polymers such as gelatin, deoxyribonucleic acid (DNA) as the ion-solvating polymers in the emissive layer of polymer LECs. Notably, we focused on DNA and DNA-lipid complex based polyelectrolytes due to the unique hybrid ionic/electronic conductivity behavior of DNA. Different solid polymer electrolytes (SPE) were tested with varying additives of salts at different ratios towards improving the ionic conductivity. Additionally, the electrochemical stability window of SPEs was defined to eliminate nonreversible electrochemical side reactions during device operation. The optoelectrical device characteristics, as well as lifetime measurements, were obtained to determine the stability of LECs. Furthermore, the surface morphology of the active layers was investigated to characterize the phase separation between SPE and emissive polymer and aggregations in thin films, which have a significant influence on the device performance. Biosolid polymer electrolytes were successfully implemented in LECs as promising materials of bio-based LECs
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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