1,720,965 research outputs found
Influence of cobalt redox couple concentration on the characteristics of liquid and quasi-solid electrolytes and on the photovoltaic parameters of dye-sensitised solar cells
No full textDye-sensitised solar cell (DSSC) is a next-generation solar energy conversion device. The electrolyte, which is one of the key components of a DSSC, greatly affects its short-circuit current density (Jsc) and open-circuit voltage (Voc) and hence, its overall performance. In this work, bis(trifluoromethane)sulfonimide (TFSI) cobalt complex was used for the first time as redox couple in DSSC, and an effort was carried out to study the effects of the varying concentration of cobalt complex redox ions on the characteristics of the prepared liquid electrolytes (LEs) and quasi-solid electrolytes (QEs), and on the photovoltaic parameters of DSSCs. Specifically, the electrolyte characteristics include the viscosity and electrical conductivity, while the photovoltaic parameters of DSSCs include Jsc, Voc, fill factor (FF) and power conversion efficiency (PCE). The viscosity of electrolytes was found to increase with increasing molar concentrations and then further increased with the addition of polyethylene oxide (PEO); the highest viscosity of 2.49 cP was obtained at 44 rpm for QE-50. The highest conductivity measured by electrochemical impedance spectroscopy was 83 mS cm− 1 for LE-50. Finally, zinc oxide-based DSSCs with platinum counter electrodes were fabricated for current-voltage measurements. Among the synthesised electrolytes, QE-35-based DSSC showed a better combination of Jsc and Voc, resulting in a PCE of 0.48%
Perovskite and perovskite inspired materials: synthesis and optoelectronic applications
No full textPerovskite materials have captivated the scientific community with their exceptional optoelectronic properties, but instability and toxicity have hindered their widespread adoption. This thesis presents innovative strategies to address these limitations, unlocking the true potential of perovskite technologies. The first project explores the utilization of FAPbBr3, a relatively stable perovskite composition, for memory device applications. In contrast to the widely studied MAPbI3, FAPbBr3 demonstrates enhanced stability, offering a viable alternative for reliable and long-lasting memory solutions. The second project delves into the microstructural engineering of AgBiI4 perovskites for solar cells. Through strategic antisolvent engineering, the researchers precisely controlled the film morphology, leading to marked improvements in device performance and paving the way for the deployment of AgBiI4 in efficient and environmentally-friendly inverted solar cell architectures. The final project tackles toxicity by investigating in-situ metal passivation for AgBiS2 solar cells. The novel passivation technique mitigated the detrimental effects of defects and grain boundaries, resulting in a significant enhancement in the photovoltaic performance of these lead-free perovskite-inspired materials. Collectively, the insights and advancements presented in this thesis lay the groundwork for a sustainable and prosperous future in perovskite-based technologies, transforming how we harness and utilize clean energy sources.</p
Two dimensional perovskites
No full textPerovskite materials have attracted tremendous attention in the field of material science and technology owing to their unique properties like tunable band gap, high carrier mobility, long diffusion length and high molar absorptivity coefficient. Among 2D perovskites the layered materials have been extensively studied in comparison to non-layered 2D perovskites. But non layered perovskites have emerged as a class of potential materials possessing unique structure and optoelectronic properties which make them suitable for many applications. This chapter will focus on the comprehensive review of synthesis, structure, properties and applications of non-layered 2D perovskites. We will discuss the crystal structure of these materials in comparison to their layered counterparts, followed by an insight of their physical properties and finally their applications. Overall, this chapter will provide insights into the potential of non-layered 2D perovskites as an emerging class of materials.</p
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
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