1,720,960 research outputs found
Room temperature processing for solid-state electrochromic devices on single substrate: From glass to flexible plastic
No full textHerein, we present, for the first time, the features of a full solid-state electrochromic (EC) device fabricated on a single substrate, made of glass as well as flexible plastic, adopting a low-cost, eco-friendly, and facile fabrication process. By combining a solution processing of Nafion electrolyte film and RF sputtering deposition at room temperature (RT) on Nafion, we obtained monolithic systems with a simplified architecture (substrate/ITO/WO3/Nafion/ITO) in which a suitable Nafion film (8 μm thick) tightly shares its interfaces with the WO3 layer and the highly transparent and conductive RF-sputtered ITO film. Compared to conventional sandwich-type EC devices using semi-solid or liquid electrolytes, the resulting devices exhibited a strong enhancement in terms of interface properties, robustness, cyclic stability, and long-term durability (at least 1000 chronoamperometric cycles). Moreover, electro-optical characterizations highlighted high transmittance modulation (49% at 650 nm), astonishing results in terms of coloration efficiency (139 cm2/C), and low energy absorption (80 mW s/cm2)
Advanced processing and characterization of Nafion electrolyte films for solid-state electrochromic devices fabricated at room temperature on single substrate
No full textThe design and development of effective solid-state electrolytes represent an emerging challenge towards the fabrication of electrochromic (EC) and multifunctional devices, such as photoelectrochromics, with benefits in terms of reduced cost, environmental impact as well as safety. Here, we present the processing and the characterization of a suitable Nafion film with the certain thickness of 8 μm used as electrolyte layer in a novel solid-state EC device fabricated at room temperature (RT) on a single substrate (both glass and plastics) with an architecture based on a substrate/ITO/WO3/Nafion-film/ITO configuration. In particular, we focused on the morphological characteristics, proton conductivity and water molecular dynamics of Nafion film in order to provide insight into the EC behavior of these novel devices. EIS analysis performed over a wide range of RH and temperature, showed good proton conductivity values (e.g. 4.42 × 10− 3 S cm− 1 at 30 °C and 50% RH), suitable for practical EC operation. At the same time, high values of water self-diffusion coefficients (D) and the spin-lattice relaxation times (T1) were measured by NMR spectroscopy, proving a similar behavior as well as the same proton conduction mechanism with that observed for thicker Nafion membrane (50 μm thick) prepared by solution casting. These findings were confirmed by the water uptake measurements since both the film and the membrane showed a water uptake value of about 24 wt%. Furthermore, a homogenous, uniform and very smooth surface (Ra of 0.94 nm) with small grain size (ca. 50 nm) was observed by SEM and AFM analysis. Noteworthy, the Nafion film ensured high optical properties, interfacial robustness and electrochemical stability to EC device: cyclability (300 CV cycles), long-term durability of at least 1000 chronoamperometric cycles
Forthcoming perspectives of photoelectrochromic devices: A critical review
No full textRe-thinking our relationship with energy resources and environmental equilibrium, towards anthropogenic sustainability, calls for innovative and energetically wise technologies. Smart devices adjusting their optical behaviour depending on the environmental conditions will allow remarkable energy savings. To this end, photoelectrochromic devices (PECDs) have captured, in the last two decades, the interest of many research groups and industrial players worldwide. These devices encompass a dual behavior, being able to generate energy and, concomitantly, deliver a smart optical response. For this reason, they are the ideal skins of future buildings, capable of modulating their behavior in response to changing external stimuli, like sunlight irradiance. PECDs have a wide range of applications, from solar shading in architectural glazing to rear view mirrors in automotives, or avionics. This review article explores the different design concepts standing at the basis of the devices that have appeared so far, shedding light on future perspectives. This work takes into account R&D issues and processing constraints as well as the potential exploitation of emerging solid-state materials promising important technological progress
Fully integrated electrochromic-OLED devices for highly transparent smart glasses
No full textFully integrated electrochromic organic light emitting diode devices for building integration and smart lighting.</p
Forthcoming perspectives of photoelectrochromic devices: a critical review
No full textRe-thinking our relationship with energy resources and environmental equilibrium, towards anthropogenic sustainability, calls for innovative and energetically wise technologies. Smart devices adjusting their optical behaviour depending on the environmental conditions will allow remarkable energy savings. To this end, photoelectrochromic devices (PECDs) have captured, in the last two decades, the interest of many research groups and industrial players worldwide. These devices encompass a dual behavior, being able to generate energy and, concomitantly, deliver a smart optical response. For this reason, they are the ideal skins of future buildings, capable of modulating their behavior in response to changing external stimuli, like sunlight irradiance. PECDs have a wide range of applications, from solar shading in architectural glazing to rear view mirrors in automotives, or avionics. This review article explores the different design concepts standing at the basis of the devices that have appeared so far, shedding light on future perspectives. This work takes into account R&D issues and processing constraints as well as the potential exploitation of emerging solid-state materials promising important technological progress
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
High colouring efficiency, optical density and inserted charge in sol–gel derived electrochromic titania nanostructures
Full text linkA pure TiO2 thin film (100–120 nm) was made from a green aqueous sol–gel precursor on FTO glass and calcined at 430 °C. It was a mix of amorphous, anatase, rutile and brookite TiO2 phases, and exhibited very good electrochromic properties over visible and NIR wavelengths with an applied bias of +0.1 V to −1.5 V. It was highly transparent showing excellent coloration with applied voltage, with transmittance modulation (ΔT) = 69.7% at 550 nm, 86% at 700 nm and an overall ΔT between 400–1650 nm of 60%, giving a very large change in optical density (ΔOD) of 1.4 at 550 nm and 2.4 at 700 nm. Cyclic voltammograms had typical peaks for TiO2 at −1.3 V for colouration and −0.9 V for bleaching, with a high separation of 0.37 V between peaks, and a charge density after charging for 25 min of Qc = 50 mC cm−2. After only 60 s and 120 s at −1.5 V, inserted charge values of 17.6 and 22 mC cm−2 were observed, leading to a high colouration efficiency (CE) of 55.9 cm2 C−1 at 550 nm. These ΔOD, ΔT, Qc and CE values are superior to any previously reported for crystalline sol–gel TiO2 films. They also possessed rapid switching times for bleaching and colouring of τb90% = 10 s and τc90% = 55 s, comparable to the best previously reported sol–gel anatase-based TiO2 films. This makes this nanomaterial an excellent candidate for smart windows and other electrochromic devices and applications
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
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