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Spectroscopy and Photoelectric Properties of 1D Single-Walled Carbon Nanotubes and 2D Molybdenum Disulfide and their Applications for Energy Storage, Photodetection and Chemical Sensing
Get PDFSingle-walled carbon nanotubes (SWNTs) offer extraordinary physical and chemical properties such as high carrier mobility and current-carrying capacity, unique optoelectronic properties, large surface area, and high electrochemical stability, thus showing great potential for applications in thin-film transistors, novel electronic and optoelectronic devices, logic circuits, solar cells, and lithium-sulfur batteries. In Chapter 1, the fundamental properties of SWNTs are introduced, including their structure, electronic and spectroscopy properties, growth method, thin film preparation, and potential applications. In chapter 2, sulfur encapsulation of SWNTs were prepared and studied by Raman and UV-Vis-NIR spectroscopy techniques. We discovered a giant Raman response to the encapsulation of sulfur in narrow diameter SWNTs with the appearance of new peaks at 319, 395 and 710 cm-1 which originate from the sulfur species within the SWNTs. The encapsulated species also shift the near-IR interband electronic transitions to lower energy by more than 10%. These effects seem to originate from the van der Waals interaction of the confined sulfur species with the walls of the SWNTs. In chapter 3, we utilized a semitransparent film of p-type semiconducting single-walled carbon nanotubes (SC-SWNTs) with an energy gap of 0.68 ±0.07 eV in combination with a molecular beam epitaxy grown n-ZnO layer to build a vertical p-SC-SWNT/n-ZnO heterojunction-based UV photodetector. The resulting device shows a current rectification ratio of 103, a current photoresponsivity up to 400 A/W in the UV spectral range from 370 to 230 nm, low dark current, and UV-to-Visible photoresponsivity ratio of 105 In chapter 4, the CVD grown single-layer MoS2 with Au metal electrodes based gas sensor was utilized. Red light illumination was used to induce a photocurrent which was employed instead of dark current for NO2 gas sensing. Resulted Au/MoS2/Au optoelectronic gas sensor showed a significant enhancement of the device sensitivity S toward ppb level of NO2 gas exposure reaching S=4.9%/ppb (4900%/ppm) and extremely low limit of detection of NO2 gas at the level of 0.2 ppb was obtained
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
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Doping Effects in Organic Low-Dimensional Conducting Materials and their Opto-Electronic Applications
Get PDFThe field of materials science has produced a variety of valuable products and technologies defining modern day civilization. While still dominated by inorganic materials, the field of organic electronics opens new technological opportunities and the access to a new class of complementary materials. Being carbon based, organic electronic materials are abundant and environment friendly, often made with low temperature processing compatible with existing inorganic materials, and highly tunable for specific optical and electronic properties. These properties have helped enable the use of organic electronic materials throughout a wide range of products. Some of these include organic light emitting diodes (OLEDs) for electronic displays and lighting, organic field effect transistors (OFETs) for device control and computing, and organic photovoltaics (OPVs) for energy generation among other uses. With their wide range of uses, the study of organic electronic materials is of high importance.In this work, we examine both highly studied and relatively new low-dimensional materials. Since their discovery in 1991, single-walled carbon nanotubes (SWNTs) have seen much interest due to their unique electronic and optical properties. Here we design all-SWNT electrochromic devices capable of modulating incoming light with fast response times (few milliseconds). The mechanism behind the device is explored through the view of an electric double layer capacitor (EDLC) and reveals important clues for the design of fast electrochromic devices.Also explored here is the substitutional doping of phenalenyl based radical molecular conductors. Through the use of substitutional doping most commonly used in silicon-based semiconductors, we demonstrate the enhancement of the electrical conductivity of some molecular conductors and modification of their magnetic properties. We also explored the possibility of using the substitutional doping to control a hysteretic phase transition and related bistable state in another phenalenyl based radical molecular conductor. Finally, the phenalenyl based radicals are incorporated into an electrochromic device which is able to modulate both visible and short-wave infrared light thus opening a novel pathway for development of a new class electrochromic materials for smart window applications
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
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