All-in-One Gel-Based Electrochromic Devices: Strengths and Recent Developments

Electrochromic devices (ECDs) have aroused great interest because of their potential applicability in displays and smart systems, including windows, rearview mirrors, and helmet visors. In the last decades, different device structures and materials have been proposed to meet the requirements of commercial applications to boost market entry. To this end, employing simple device architectures and achieving a competitive electrolyte are crucial to accomplish easily implementable, high-performance ECDs. The present review outlines devices comprising gel electrolytes as a single electroactive layer (“all-in-one”) ECD architecture, highlighting some advantages and opportunities they offer over other electrochromic systems. In this context, gel electrolytes not only overcome the drawbacks of liquid and solid electrolytes, such as liquid’s low chemical stability and risk of leaking and soil’s slow switching and lack of transparency, but also exhibit further strengths. These include easier processability, suitability for flexible substrates, and improved stabilization of the chemical species involved in redox processes, leading to better cyclability and opening wide possibilities to extend the electrochromic color palette, as discussed herein. Finally, conclusions and outlook are provided.This work has been partially supported by the European Union’s Horizon 2020 research and innovation program under the INNPAPER project (grant agreement No. 760876)

Titanium dioxide in chromogenic devices: Synthesis, toxicological issues, and fabrication methods

none3noThe use of titanium dioxide (TiO2) within two specific classes of devices, namely electrochromic and photoelectrochromic, is described hereafter, with respect to its inherent properties and chromogenic features within architectures that have appeared so far, in this field. The new research trends, involving the applications of TiO2 in chromogenic materials are reported, with particular attention paid to the techniques used for film deposition as well as the synthesis of nanoparticles. Furthermore, the main studies concerning its chemical-physical properties and approaches to its chemical syntheses and fabrication are reviewed, with special regard to “green” routes. In addition, the main aspects relating to toxicological profiles are exposed, with reference to nanoparticles and thin films.openDe Matteis V.; Cannavale A.; Ayr U.De Matteis, V.; Cannavale, A.; Ayr, U

Influence of immersion on user's spatial presence and memory in virtual environments

This study examines the influence of immersion on users' sense of spatial presence and spatial memory in virtual environments. The single factor was systematically manipulated in three conditions. A sample of 32 participants was used to test the study hypotheses. This study employed a between-subject design, and participants were randomly assigned to one of the three experimental conditions. The results from statistical analysis of covariance (ANCOVA) revealed the influence of immersion on the spatial presence and spatial memory. The results of this study revealed that higher level of immersion including a wider field of view and the stereoscopic display did lead to a greater sense of presence and improved spatial memory performance. This study has practical implications across various domains including architectural design and visualization, developing virtual reality systems, and training simulators.Includes bibliographical reference

Understanding the immersive experience: Examining the influence of visual immersiveness and interactivity on spatial experiences and understanding

Advances in computer graphics have enabled us to generate more compelling 3D virtual environments. 'Immersive experience' in these environments result from a combination of immersion and interactivity. As such, various disciplines have started adopting 3D technology for enhancing spatial understanding and experience. But the impact of the immersive experience on spatial understanding and experience remains unclear. This study utilized a controlled, between-subjects experiment to systematically manipulate a virtual reality system's technology affordances (stereoscopy, field of view, and navigability) and measure their impact. Participants, N=120, explored a virtual office and completed a questionnaire on the experience and tasks evaluating their understanding of the space. The results indicated that visual immersion had the greatest impact on understanding but, better experiences were gained when visual immersion was combined with greater interactivity. These findings support the notion the immersive experience is important for the comprehension of virtual spaces. This study overall served to provide insight into the role of the immersive experience on the comprehension of virtual spaces. The findings advance theories of spatial presence and immersion, support the use of methods which look at technology as affordances rather than entities, and support the use of 3D technology for communicating spatial information as in the case of architecture and fire-fighter training

Data systems elements technology assessment and system specifications, issue no. 1

The ability to satisfy the objectives of future NASA Office of Applications Programs is dependent on technology advances in a number of areas of data systems. The technology of end-to-end data systems (space generator elements through ground processing, dissemination, and presentation, is examined in terms of state of the art, trends, and projected developments in the 1980 to 1985 timeframe. Capability is considered in terms of elements that are either commercially available or that can be implemented from commercially available components with minimal development

Data systems elements technology assessment and system specifications, issue no. 2

The ability to satisfy the objectives of future NASA Office of Applications programs is dependent on technology advances in a number of areas of data systems. The hardware and software technology of end-to-end systems (data processing elements through ground processing, dissemination, and presentation) are examined in terms of state of the art, trends, and projected developments in the 1980 to 1985 timeframe. Capability is considered in terms of elements that are either commercially available or that can be implemented from commercially available components with minimal development

Rational control of hydrothermal nanowire synthesis and its applications

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2010.Includes bibliographical references (p. 172-182).Hydrothermal nanowire synthesis is a rapidly emerging nanowire discipline that enables low temperature growth and batch process. It has a major impact on the development of novel energy conversion devices, high density electronics, and optical devices. However, detailed growth mechanism is still in early stage of its development. This thesis presents the fundamental understanding of controlled zinc oxide nanowire synthesis in a hydrothermal system based on thermodynamic / kinetic analysis of heterogeneous chemical reactions. Governing parameters of hydrothermal growth were evaluated with experimental growth rates and calculated solubility plots. Supersaturation was shown to be a key parameter for the hydrothermal nanowire synthesis. Morphology control of the nanowire synthesis was tested with various additional cations during synthesis. Changes in morphology and aspect ratio with different cations were explained by electrostatic competing ion model. Based on experimental results and complex ion charge distribution, the growth direction was biased via electrostatic competition from cation-complexes that adsorb to the crystal in a face-specific manner, thereby reducing zinc ion-complex adsorption and suppressing growth along that face. Dynamic control of nanowire synthesis was investigated under microfluidic environment with continuous flow. Microfluidic growth conditions were analyzed with the parametric experiments and finite element modeling. Nanowire growth under complex geometry was also evaluated. This rational control of hydrothermal nanowire synthesis was applied to fabricate high efficiency alternative current electroluminescent devices, in-situ fabricated light emitting diodes, photovoltaic devices, and field emission devices.by Jaebum Joo.Ph.D

Vers un afficheur électrochrome sur papier : Electronique imprimée pour l’emballage sécurisé du futur

This study aims at the development of an electrochromic display on paper, activated by a smartphone as solution for counterfeit. A novel deposition method at room temperature of WO3 thin films was developed using a UV treatment. 5-layer electrochromic device (ECD), based on WO3 on paper, Prussian blue, and an electrolyte membrane, showed good electrochemical stability for more than 500 cycles associated with an optical contrast in reflectance ΔR of 13% at -1 V. In order to minimize the activation potential, ECDs with simplified architecture, derived from 5-layer conventional configuration have been developed in a second part of this work. 4-layer ECDs were constructed by replacing the counter-electrode and conductive layer by a single metal layer. In addition, the use of an electrochromic conducting material leads to 3-layer device. 4 and 3-layer ECDs exhibit high electrochromic performances at only -0.7 V with nice stability for more than 500 cycles. The first prototype integrated on perfume packaging, with 4-layer ECD based on PEDOT (poly(3,4-ethylenedioxythiophene), ionic liquid electrolyte polymerized by UV-varnish, and Ag as counter-electrode was successfully activated by a smartphone in less than 5.3 seconds for an activation energy of 0.33 mJ.cm-2.La finalité de cette étude était la réalisation d’un afficheur électrochrome sur papier activable par un smartphone comme solution anti-contrefaçon. La nature cellulosique du substrat et la faible énergie délivrée par le smartphone ont représenté deux contraintes majeures dans de ce travail de thèse. Ainsi, une nouvelle méthode originale de dépôt à température ambiante de films minces WO3 a été développée en utilisant un traitement UV. Le premier dispositif électrochrome couplant le film WO3 sur papier, le Bleu de Prusse, et une membrane électrolytique plastifiée, a montré une bonne stabilité électrochimique associée à un contraste optique ΔR de 13 % pour une tension d’activation de -1 V. En vue de minimiser la tension d’activation, de nouveaux dispositifs électrochromes, à architecture simplifiée, dérivés d’une configuration classique à 5 couches ont été mis au point. Le remplacement du matériau de contre électrode et du conducteur électronique par un matériau métallique unique a conduit à des dispositifs à 4 couches. De plus, l’utilisation d’un matériau électrochrome conducteur a permis de s’affranchir de la couche conductrice électronique adjacente à l’électrode de travail menant à des dispositifs encore plus simplifiés à 3 couches. Les dispositifs simplifiés se caractérisent par des performances électrochromes très intéressantes pour une activation à seulement -0,7 V et présentent une stabilité électrochimique sur plus de 500 cycles. Le premier prototype sur emballage de parfum, à base d’afficheur électrochrome constitué de PEDOT, d’électrolyte liquide ionique polymérisé par vernis UV, et de contre électrode d’Ag, a été activé avec succès par un smartphone en moins de 5,3 secondes pour une énergie d’activation de 0,33 mJ.cm-2