1,721,048 research outputs found
Processing and characterization of a TiO2 paste based on small particle size powders for dye-sensitized solar cell semi-transparent photo-electrodes
No full textThe formulation and the preparation of a TiO2 paste for dye-sensitized solar cell technology are proposed. The TiO2 paste is characterized in terms of rheology, morphology, cross section, specific surface area, and average pore size. A conversion efficiency of 7.42% without any chemical treatment or scattering layer was obtained using the optimal thickness of 11 mu m as carried out in this work. The results over different batches of the paste confirm the stability and the reproducibility. The characterization of the TiO2 semi-transparent film is completed by investigating the dye adsorption saturation time after cyclic dye dipping steps through UVVis spectra measurements. Copyright (C) 2011 John Wiley & Sons, Ltd
Efficient and stable perovskite large area cells by low-cost fluorene-xantene-based hole transporting layer
Full text linkAmong the new generation photovoltaics, perovskite solar cell (PSC) technology reached top efficiencies in a few years. Currently, the main objective to further develop PSCs is related to the fabrication of stable devices with cost-effective materials and reliable fabrication processes to achieve a possible industrialization pathway. In the n-i-p device configuration, the hole transporting material (HTM) used most is the highly doped organic spiro-fluorene-based material (Spiro-OMeTAD). In addition to the high cost related to its complex synthesis, this material has different issues such as poor photo, thermal and moisture stability. Here, we test on small and large area PSCs a commercially available HTM (X55, Dyenamo) with a new core made by low-cost fluorene-xantene units. The one-pot synthesis of this compound reduces 30 times its cost with respect to Spiro-OMeTAD. The optoelectronic performances and properties are characterized through JV measurement, IPCE (incident photon to current efficiency), steady-state photoluminescence and ISOS stability test. SEM (scanning electron microscope) images reveal a uniform and pinhole free coverage of the X55 HTM surface, which reduces the charge recombination losses and improves the device performance relative to Spiro-OMeTAD from 16% to 17%. The ISOS-D-1 stability test on large area cells without any encapsulation reports an efficiency drop of about 15% after 1000 h compared to 30% for the reference case
A Novel Class of Dye-Sensitized Solar Modules. Glass-Plastic Structure for Mechanically Stable Devices
No full textLow temperature process of homogeneous and pinhole free Perovskite layers for fully coated photovoltaic devices up to 256 cm2 area at ambient condition
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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
Prospective life cycle assessment of third-generation photovoltaics at the pre-industrial scale: A long-term scenario approach
No full textThe development of sustainable technologies for energy generation should necessarily undergo sustainability assessment. A well-recognized, valuable tool to accomplish this task is the life cycle assessment. In particular, prospective life cycle assessment can provide the useful methodological framework to calculate eco-profiles of third-generation photovoltaic technologies with a future-oriented perspective. In this paper, we present the life cycle assessment of a real semi-industrial production process of dye-sensitized solar modules performed by the Italian Dyepower consortium. Due to the unique availability of primary data at the semi-industrial scale, an extensive inventory is built and a long-term approach is implemented based on predictive scenarios featuring technological development and energy mix evolution. The aim is to evaluate of the potential of this technology from an environmental sustainability perspective as a renewable source for electricity generation in the future European energy market, namely, for building integrated applications. The results demonstrate the well-performing environmental footprint of the device and its pre-industrial fabrication process that, coupled with architectural versatility and remarkable performance in low intensity and diffuse light, make this technology suitable for different niches of the energy market. This analysis also highlights challenges in the fabrication process and identifies the technological improvements, alternative materials and engineering solutions that would further improve the environmental footprint of dye sensitized solar modules. Finally, the proposed life cycle assessment approach, provided that detailed and robust primary data are available, is valid for the investigation of the eco-profile of third generation photovoltaic technologies in terms of environmental sustainability in the European context
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