1,720,978 research outputs found
Design of electron mediators for DSSC and Redox Flow Batteries and characterization of sensitized photoanodes for water splitting.
No full textOrganic‐Inorganic Photosynthetic Interfaces Built on Intertwined WO3 Nanosheets for Enhanced HBr/H2O Photoanodic Oxidations
No full textUsing a sacrificial ZnO template, this study report the fabrication of fluorine-doped tin oxide (FTO)-based photoanodes displaying a porous network of interconnected 3D-tungsten oxide nanosheets (WO3 3D-NS), with diameter/thickness distribution respectively in the range 0.20–0.94 μm and 10–40 nm, leading to record aspect ratios (≈100) with respect to literature benchmarks (≈10) and dominant {001} facets. WO3 3D-NS provide an ideal platform for shaping hybrid photosynthetic interfaces by deposition of supramolecular perylenebisimide polymers (PBIn). The combined WO3 3D-NS|PBIn are probed for photoelectrochemical HBr splitting using low energy photons (λ > 450 nm), with up to a 83% increase of the state-of-the-art performance based on WO3-analogs (J > 0.3 mA cm−2 at 0.85 V vs. reversible hydrogen electrode (RHE)). Structure versus reactivity comparison with WO3 microplates (WO3 MP) and inverse opal (WO3 IO) points to a favorable enhanced active surface area of WO3 3D-NS exposing dominant {001} facets, which promote PBI sensitization and charge transfer at the photoanode|electrolyte interface. Building on this technology, a >50% improvement of photoanodic water splitting is achieved using WO3 3D-NS photoanode as platform for the core-shell self-assembly of the PBI based quantasome architecture (QS), templated around the tetra-ruthenated polyoxometalate as oxygen evolving catalyst ({[PBI]5Ru4POM}n). Rendering the bio-inspired QS on the WO3 3D-NS surface yields an incident-photon-to-current-conversion efficiency (IPCE) of 0.67%, using green photons for oxygenic photosynthesis (500 nm at 0.91 V vs. RHE) which stems from a multiheterojunction molecular array for light harvesting and charge transport, representing a significative advancement in the field
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
On the stability of manganese tris(β-diketonate) complexes as redox mediators in DSSCs
No full textThe photoelectrochemical properties and stability of dye sensitized solar cells containing Mn(b-diketonato)3 complexes, [MnIII(acac)3] (1) (acac = acetylacetonate), [MnIII(CF2)3] (2) (CF2 = 4,4-difluoro-1-phenylbutanate-1,3-dione), [MnIII(DBM)3] (3) (DBM = dibenzoylmethanate), [MnII(CF2)3]TBA (TBA = tetrabutylammonium) (4) and [MnII(DBM)3]TBA (5), have been evaluated. At room temperature, the complexes undergo ligand exchange with 4-tert-butyl-pyridine, an additive commonly used in the solar device to reduce charge recombination at the photoanode. An increased device stability was achieved by using the Z907 dye and passivating the photoanode with short chain siloxanes. It was also found that the Mn(II)/(III) couple is involved in the dye regeneration process, instead of Mn(III)/(IV) (E1/2 4 1 V vs. SCE) previously indicated in the literature
Single Walled Carbon Nanohorns as Catalytic Counter Electrodes for Co(III)/(II) Electron Mediators in Dye Sensitized Cells
No full textThe electrochemical properties of both pristine single walled carbon nanohorns (SWCNHS) and their chemically oxidized form (ox-SWCNHS) spray coated onto fluorine doped SnO2 (FTO) were investigated in the framework of the fabrication of cobalt based transparent dye sensitized solar cells (DSSCs). These new nanocarbon substrates, evaluated in conjunction with the Co(bpy)3 2+/3+ (bpy = 2,2′-bipyridine) redox mediator, are endowed with excellent electrocatalytic properties, ease of fabrication, and very promising stability and display a great potential for replacing the best noble metal and conductive polymer catalytic materials in the building of semitransparent counter electrodes in new generation photoelectrochemical devices
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