All sol-gel electrochromic smart windows: CeO2-TiO 2/Ormolyte/WO3

A solid state system having the configuration WO 3/Ormolyte/CeO2-TiO2 has been assembled. Syntheses routes for tungsten oxide WO3, and cerium-titanium CeO 2-TiO2 oxide sols, were developed. A novel solid electrolyte - Ormolyte is reported, which were obtained by the sol-gel process, they have a chemical stability due to the covalent bonds between the inorganic and organic phase, and were prepared with different [O]/[L] ratios, being the best for [O]/[L]=15. The variation of transmittance of the electrochromic device using the ormolyte [O]/[L]=15 was 35% (colored state) and 77% (bleached state).

Gelatin-based protonic electrolyte for electrochromic windows

Proton-conducting gel polymer electrolytes based on gelatin plasticized with glycerol and containing acetic acid were investigated, characterized, and applied to electrochromic window. For glycerol contents varying from 7% to 48%, the conductivity of the uniform and predominantly amorphous gel electrolyte was found to follow a Vogel-Tamman-Fulcher behavior with the temperature. Typically, for the electrolyte chosen to make 7 x 2 cm(2) electrochromic smart window with the configuration: glass/fluor-doped tin oxide (FTO)/WO(3)/gelatin electrolyte/CeO(2)-TiO(2)/FTO/glass and containing 28% of glycerol, the conductivities were found to be of the order of 5 x 10(-5) S/cm at room temperature and 3.6 x 10(-4) S/cm at 80 A degrees C. The device was characterized by spectroelectrochemical techniques and was tested up to 10,000 cycles showing a fast coloring/bleaching behavior, where the coloring process was achieved in 10 s and the bleaching in 2 s. The transmission variation at the wavelength of 550 nm was about 15%. The cyclic voltammograms showed a very good reversibility of the cathodic/anodic processes, and the charge density was about 3.5 mC/cm(2). The memory tests showed that the transmittance in the colored state increased by 8% in 90 min after removing the potential.

Studies On The Electrical Properties Of Some Crystalline Organic Compounds And Conducting Polymers

Solid electrolytes for applications like chemical sensing, energy storage, and conversion have been actively investigated and developed since the early sixties. Although of immense potential, solid state protonic conductors have been ignored in comparison with the great interest that has been shown to other ionic conductors like lithium and silver ion conductors. The non-availability of good, stable protonic conductors could be partly the reason for this situation. Although organic solids are better known for their electrical insulating character, ionic conductors of organic origin constitute a recent addition to the class of ionic conductors. However, detailed studies (N1 such conductors are scarce. Also the last decade has witnessed an unprecedented boom in research on organic "conducting polymers". These newly devised materials show conductivity spanning from insulator to metallic regimes, which can be manipulated by appropriate chemical treatment. They find applications in devices ranging from rechargeable batteries to "smart windows". This thesis mainly deals with the synthesis and investigations on the electrical properties of (i) certain organbc protonic conductors derived from ethylenediamine and (ii) substituted polyanilines

Synthesis, Characterization and Applications of Hybrid Nanocomposites of TiO2 With Conducting Polymers

A nanocomposite is a multiphase solid material where one of the phases has one, two or three dimensions of less than 100 nanometers (nm), or structures having nano-scale repeat distances between the different phases that make up the material. In the broadest sense this definition can include porous media, colloids, gels and copolymers, but is more usually taken to mean the solid combination of a bulk matrix and nano-dimensional phase(s) differing in properties due to dissimilarities in structure and chemistry. The mechanical, electrical, thermal, optical, electrochemical, catalytic properties of the nanocomposite will differ markedly from that of the component materials. Size limits for these effects have been proposed, <5 nm for catalytic activity, <20 nm for making a hard magnetic material soft, <50 nm for refractive index changes, and <100 nm for achieving superparamagnetism, mechanical strengthening or restricting matrix dislocation movement. Conducting polymers have attracted much attention due to high electrical conductivity, ease of preparation, good environmental stability and wide variety of applications in light-emitting, biosensor chemical sensor, separation membrane and electronic devices. The most widely studied conducting polymers are polypyrrole, polyaniline, polythiophene etc. Conducting polymers provide tremendous scope for tuning of their electrical conductivity from semiconducting to metallic region by way of doping and are organic electro chromic materials with chemically active surface. But they are chemically very sensitive and have poor mechanical properties and thus possessing a processibility problem. Nanomaterial shows the presence of more sites for surface reactivity, they possess good mechanical properties and good dispersant too. Thus nanocomposites formed by combining conducting polymers and inorganic oxide nanoparticles possess the good properties of both the constituents and thus enhanced their utility. The properties of such type of nanocomposite are strongly depending on concentration of nanomaterials to be added. Conducting polymer composites is some suitable composition of a conducting polymer with one or more inorganic nanoparticles so that their desirable properties are combined successfully. The composites of core shell metal oxide particles-conducting polymer combine the electrical properties of the polymer shell and the magnetic, optical, electrical or catalytic characteristics of the metal oxide core, which could greatly widen their applicability in the fields of catalysis, electronics and optics. Moreover nanocomposite material composed of conducting polymers & oxides have open more field of application such as drug delivery, conductive paints, rechargeable batteries, toners in photocopying, smart windows, etc.The present work is mainly focussed on the synthesis, characterization and various application studies of conducting polymer modified TiO2 nanocomposites. The conclusions of the present work are outlined below, Mesoporous TiO2 was prepared by the cationic surfactant P123 assisted hydrothermal synthesis route and conducting polymer modified TiO2 nanocomposites were also prepared via the same technique. All the prepared systems show XRD pattern corresponding to anatase phase of TiO2, which means that there is no phase change occurring even after conducting polymer modification. Raman spectroscopy gives supporting evidence for the XRD results. It also confirms the incorporation of the polymer. The mesoporous nature and surface area of the prepared samples were analysed by N2 adsorption desorption studies and the mesoporous ordering can be confirmed by low angle XRD measurementThe morphology of the prepared samples was obtained from both SEM & TEM. The elemental analysis of the samples was performed by EDX analysisThe hybrid composite formation is confirmed by FT-IR spectroscopy and X-ray photoelectron spectroscopyAll the prepared samples have been used for the photocatalytic degradation of dyes, antibiotic, endocrine disruptors and some other organic pollutants. Photocatalytic antibacterial activity studies were also performed using the prepared systemsAll the prepared samples have been used for the photocatalytic degradation of dyes, antibiotic, endocrine disruptors and some other organic pollutants. Photocatalytic antibacterial activity studies were also performed using the prepared systems Polyaniline modified TiO2 nanocomposite systems were found to have good antibacterial activity. Thermal diffusivity studies of the polyaniline modified systems were carried out using thermal lens technique. It is observed that as the amount of polyaniline in the composite increases the thermal diffusivity also increases. The prepared systems can be used as an excellent coolant in various industrial purposes. Nonlinear optical properties (3rd order nonlinearity) of the polyaniline modified systems were studied using Z scan technique. The prepared materials can be used for optical limiting Applications. Lasing studies of polyaniline modified TiO2 systems were carried out and the studies reveal that TiO2 - Polyaniline composite is a potential dye laser gain medium.

Development of Electrochromic Devices

Electrochromic devices (ECD) are systems of considerable commercial interest due to their controllable transmission, absorption and/or reflectance. For instance, these devices are mainly applied to glare attenuation in automobile rearview mirrors and also in some smart windows that can regulate the solar gains of buildings. Other possible applications of ECDs include solar cells, small-and large-area flat panel displays, frozen food monitoring and document authentication also are of great interest. Over the past 20 years almost 1000 patents and 1500 papers in journals and proceedings have been published with the keyword ""electrochromic windows"". Most of these documents report on materials for electrochromic devices and only some of them about complete systems. This paper describes the first patents and some of the recent ones on ECDs, whose development is possible due to the advances in nanotechnology.

Efeitos fotocrômico e termocrômico em ormosils dopados com azobenzenos

The sol-gel process and the wide variety of alkoxides commercially available have facilitated the processing of various Organic-Inorganic Hybrid Materials. In general, the hybrids are excellents matrix to incorporate organic or inorganic dopants that presents photochromic, thermochromic, and halochromic effects and in some cases photorefractive effects. The GPTS-TEOS hybrid matrix when deposited in the form of film is very resistant, adherent, has excellent transparency in visible region and allows to be doped with various azo-dye and metal salts of unusual oxidation states. One of the main characteristics of the azo-dyes when immersed in some hybrid matrix , is the capacity to isomerizes through group Azo (-N = N-) would can be commutated between the Cis (Z) and Trans (E) configurations by means of light or heat. Our goal was through the sol-gel process to prepare hybrid films of GPTS-TEOS doped with azo-dyes Methyl Red and Disperse Red 1, and characterize them optically. The characterizations are performed using techniques of UV / Vis spectroscopy, to identify changes in the absorption band of azo-dyes in the presence of optical pumping, (photochromic effects), in function of temperature (thermochromic effect). These properties are of wide scientific and technological interest because they will contribute to the confection Smart Windows (windows sensible to light), temperature sensors monitored optically and also in the recording of amplitude and phase diffraction gratings

Propriedades estruturais e espectroscópicas de WO3 e WO3:Eu3+

Used as catalysts even in organic and inorganic molecules, as additives on catalysts, electrochromic films on smart windows the tungsten trioxide have been largely studied on the lasts decades, but there is just a few about it's luminescence. Using as precursors nitric acid and sodium tungstate the tungsten trioxide were been prepared thru wet process then treating on thermic and hydrothermal treatments. Where been evaluated the effects of methodology, nitric acid concentration, duration and temperature of treatments. The samples were characterized by X-ray diffraction (XRD), Raman scattering spectroscopy (RSS), Fourier transformed infrared spectroscopy, photoluminescence spectroscopy (PLS) and X-ray excited optical luminescence (XEOL). Hydrated phases of tungsten trioxide were obtained through hydrothermal treatments and the non-hydrated phases occur with thermic treatments. The acid concentration has the ability to determine the major phase formed as well the temperature determine the hydratation of the product. With lower temperatures dihydrate phase were preferable formed and with the rise of temperature, the water molecules were lost up to the fractionary hydratation and then the non-hydrated phase with higher temperatures depending on the atmosphere used on the thermal treatment. Doping the system with europium ions even substituting tungsten or in the interstices of the matrix were not been successful, as well the XEOL spectroscopy intensity were null and quite low for ultraviolet and visible excitation photoluminescence because of oxygen defect levels localized into the prohibited band.

Propriedades estruturais e espectroscópicas de WO3 e WO3:Eu3+

Used as catalysts even in organic and inorganic molecules, as additives on catalysts, electrochromic films on smart windows the tungsten trioxide have been largely studied on the lasts decades, but there is just a few about it's luminescence. Using as precursors nitric acid and sodium tungstate the tungsten trioxide were been prepared thru wet process then treating on thermic and hydrothermal treatments. Where been evaluated the effects of methodology, nitric acid concentration, duration and temperature of treatments. The samples were characterized by X-ray diffraction (XRD), Raman scattering spectroscopy (RSS), Fourier transformed infrared spectroscopy, photoluminescence spectroscopy (PLS) and X-ray excited optical luminescence (XEOL). Hydrated phases of tungsten trioxide were obtained through hydrothermal treatments and the non-hydrated phases occur with thermic treatments. The acid concentration has the ability to determine the major phase formed as well the temperature determine the hydratation of the product. With lower temperatures dihydrate phase were preferable formed and with the rise of temperature, the water molecules were lost up to the fractionary hydratation and then the non-hydrated phase with higher temperatures depending on the atmosphere used on the thermal treatment. Doping the system with europium ions even substituting tungsten or in the interstices of the matrix were not been successful, as well the XEOL spectroscopy intensity were null and quite low for ultraviolet and visible excitation photoluminescence because of oxygen defect levels localized into the prohibited band.

Novel polymer electrolytes based on gelatin and ionic liquids

This study describes the results of the characterization of polymer electrolytes using gelatin matrix doped with europium triflate and/or different ionic liquids. Samples of solvent-free electrolytes were prepared and characterized by ionic conductivity measurements, thermal analysis, electrochemical stability, X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectroscopy. Electrolyte samples are thermally stable up to approximately 220 degrees C. All the materials synthesized are totally amorphous. The room temperature conductivity maximum of this electrolyte system is based on ionic liquid 1-ethyl-3-methylimidazolium acetate, (C(2)mim)(OAc) (1.18 x 10(-4) S cm(-1) at 30 degrees C). The electrochemical stability domain of all samples is about 2.0 V versus Li/Li+. This new series of materials represents a promising alternative in polymer electrolytes research field. The preliminary studies carried out with electrochromic devices (ECDs) incorporating optimized compositions have confirmed that these materials may perform as satisfactory multifunctional component layers in the field of "smart windows". This new materials, will open a land of promising applications in many areas: optics, energy, medicine for example as membranes and separation devices, ECD-based devices, sensors, etc. (C) 2012 Elsevier B.V. All rights reserved.

Potentiostatic Reversible Photoelectrochromism: An Effect Appearing in Nanoporous TiO2/Ni(OH)2 Thin Films

In the field of energy saving, finding composite materials with the ability of coloring upon both illumination and change of the applied electrode potential keeps on being an important goal. In this context, chemical bath deposition of Ni(OH)2 into nanoporous TiO2 thin films supported on conducting glass leads to electrodes showing both conventional electrochromic behavior (from colorless to dark brown and vice versa) together with photochromism at constant applied potential. The latter phenomenon, reported here for the first time, is characterized by fast and reversible coloration upon UV illumination. The bleaching kinetics shows first order behavior with respect to the NiIII centers in the film, and an order 1.2 with respect to electrons in the TiO2 film. From a more applied point of view, this study opens up the possibility of having two-mode smart windows showing not only conventional electrochromism but also reversible darkening upon illumination.

Piattaforme per Internet of Things: Windows IoT Core come caso di studio

Questa tesi si pone l'obiettivo di esplorare alcuni aspetti di uno dei settori più in crescita in questi anni (e nei prossimi) in ambito informatico: \textbf{Internet of Things}, con un occhio rivolto in particolar modo a quelle che sono le piattaforme di sviluppo disponibili in questo ambito. Con queste premesse, si coglie l'occasione per addentrarsi nella scoperta della piattaforma realizzata e rilasciata da pochi mesi da uno dei colossi del mercato IT: Microsoft. Nel primo capitolo verrà trattato Internet of Things in ambito generale, attraverso una panoramica iniziale seguita da un'analisi approfondita dei principali protocolli sviluppati per questa tecnologia. Nel secondo capitolo verranno elencate una serie di piattaforme open source disponibili ad oggi per lo sviluppo di sistemi IoT. Dal terzo capitolo verrà incentrata l'attenzione sulle tecnologie Microsoft, in particolare prima si tratterà Windows 10 in generale, comprendendo \emph{UWP Applications}. Di seguito, nel medesimo capitolo, sarà focalizzata l'attenzione su Windows IoT Core, esplorandolo dettagliatamente (Windows Remote Arduino, Modalità Headed/Headless, etc.). Il capitolo a seguire concernerà la parte progettuale della tesi, comprendendo lo sviluppo del progetto \textbf{Smart Parking} in tutte le sue fasi (dei Requisiti fino ad Implementazione e Testing). Nel quinto (ed ultimo) capitolo, saranno esposte le conclusioni relative a Windows IoT Core e i suoi vantaggi/svantaggi.

An Internet of Things approach for managing smart services provided by wearable devices.

The Internet of Things (IoT) is growing at a fast pace with new devices getting connected all the time. A new emerging group of these devices are the wearable devices, and Wireless Sensor Networks are a good way to integrate them in the IoT concept and bring new experiences to the daily life activities. In this paper we present an everyday life application involving a WSN as the base of a novel context-awareness sports scenario where physiological parameters are measured and sent to the WSN by wearable devices. Applications with several hardware components introduce the problem of heterogeneity in the network. In order to integrate different hardware platforms and to introduce a service-oriented semantic middleware solution into a single application, we propose the use of an Enterprise Service Bus (ESB) as a bridge for guaranteeing interoperability and integration of the different environments, thus introducing a semantic added value needed in the world of IoT-based systems. This approach places all the data acquired (e.g., via Internet data access) at application developers disposal, opening the system to new user applications. The user can then access the data through a wide variety of devices (smartphones, tablets, computers) and Operating Systems (Android, iOS, Windows, Linux, etc.).