Sustainable Built Environments Senior Capstone Project / Electrochromic glass is a type of smart glass, a new technology that has potential to reduce the amount of sunlight entering a building by changing its physical properties. The purpose of this study is to understand the properties of electrochromic glass and determine if it is a viable alternative to conventional single pane and double pane glass in the Tucson area. Using research and statistics from smart glass production companies, a comparative analysis will be done using the building simulation software Energy-10. It was found that when compared to single pane glass, double pane glass had a decrease of 7.21% in energy cost and electrochromic glass had a decrease of 9.81%. For the used building model, this meant a return investment in 30 and a half years. While electrochromic glass is a new clean method of energy usage reduction, it currently cannot return the consumers initial investment within a desirable time span.

TiO2 is a fascinating material proving its usefulness in a wide range of applications. In catalytic and electrochemical applications, it has been utilized as a stable semiconductor electrode for the conversion of solar energy into chemical or electrical energy. Especially, the cleavage of water over TiO2 using light energy is well known. The degradation of organic pollutants present in waste water, using irradiated dispersions of TiO2, is a fast growing field in basic and applied research. One can also mention that the use of TiO2 in pigments sun lotions and toothpastes and its biocompatibility. The EC phenomena of TiO2 had been reported first by Inoue et al., who produced the films by hydrolysis of titanium tetraoxide. The film show cathodic coloration and turned dark blue. The LPD-TiO2 film deposited at 40 ¢J with (NH4)2TiF6 for 0.1 M and 0.2 M for boric acid. The films were transparent in visible range and can be colored in a solution 1M LiClO4 + propylene carbonate. The deposition rate can be controlled perfectly about 43 nm/h. The 270-nm thickness LPD-TiO2 film gives the best transmittance difference at 550 nm.

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The electrochromic materials are capable of changing their optical properties (transmittance and/or reflectance) under applied electric potentials; when that potential is stopped or it goes on reverse, these materials keep or return to its original optical state in a reversible way. The variation of the optical properties is caused by of insertion/extraction of cations in the electrochromic film. The as-deposited LPD-NiO film is also uniform and transparent. The LPD-NiO film is light gray after coloring; the transparency ratio (£GT%) can reach about 48% at the wavelength of 550 nm. After annealing in 300oC, the bleached state almost approaches that of original state before colored. We expect that the electrochromic device combined LPD-TiO2 and LPD-NiO films can enhance the coloration efficiency.

Electrochromic smart windows offer a viable route to reducing the consumption of buildings energy, which represents about 30% of the worldwide energy consumption. Smart windows are far more compelling than current static windows in that they can dynamically modulate the solar spectrum depending on climate and lighting conditions or simply to meet personal preferences. The latest generation of smart windows relies on nominally transparent metal oxide nanocrystal materials whose chromism can be electrochemically controlled using the plasmonic effect. Plasmonic electrochromic materials selectively control the near infrared (NIR) region of the solar spectrum, responsible for solar heat, without affecting the visible transparency. This is in contrast to conventional electrochromic materials which block both the visible and NIR and thus enables electrochromic devices to reduce the energy consumption of a building or a greenhouse in warm climate regions due to enhancements of both visible lighting and heat blocking. Despite this edge, this technology can benefit from important developments, including low-cost solution-based manufacturing on flexible substrates while maintaining durability and coloration efficiency, demonstration of independent control in the NIR and visible spectra, and demonstration of self-powering capabilities. This thesis is focused on developing low-temperature and all-solution processed plasmonic electrochromic devices and dual-band electrochromic devices. We demonstrate new device fabrication approaches in terms of materials and processes which enhance electrochromic performance all the while maintaining low processing temperatures. Scalable fabrication methods are used to highlight compatibility with high throughput, continuous roll-to-roll fabrication on flexible substrates. In addition, a dualband plasmonic electrochromic device was developed by combining the plasmonic layer with a conventional electrochromic ion storage layer. This enables independent control of the transmittance of NIR and visible spectra and is done without time- and energyintensive synthesis and processing methods. We have fabricated self-powered smart windows by integrating the plasmonic and dual-band devices with organic photovoltaic mini-modules and introduced static color bias with the help of photonic crystals to explore a few possibilities of multi-platform building integration.

Tungsten trioxide (WO3) films are important for various optical devices and especially for electrochromic materials. Sputtered WO3 thin films were deposited on conductive glass substrate (ITO/glass) by RF sputtering from a WO3 target(diameter 2¡¨x 6 mm) in a reactive atmosphere of oxygen and argon flow ratio(0 to 1) mixture in a total gas pressure of 10m Torr. The RF power was 100W operating at 13.56MHz.We will improve the WO3 films by post-annealing in different atmosphere ambient. In addition, to prepare treatment solution of growing WO3 films were dissolved tungsten to aqueous which mixed hydrofluoric acid and nitric acid until it supersaturate. This solution was then diluted to 0.02 M of tungsten ions with distilled water. And we can get the treatment solution (WO3-HF aqueous). The WO3 thin films have been deposited at 40oC with the treatment solution (WO3-HF aqueous) which full of W ions, the 0.1M boric acid (H3BO3) solution and added aluminium metal by liquid phase deposition (LPD) technique. The deposition rate could be controlled to 45 nm/h. In our experiment, the WO3 films morphology and thickness was characterized by scanning electron microscopy(SEM), structure was characterized by X-ray diffraction(XRD), chemical properties was characterized by X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared spectroscopy(FT-IR), optical properties was characterized by spectrophotometer(MP-100M), and electrochromic characterized by cyclic voltammetry(CHI627C). In our results, it will be improved the optical and electrochromic properties of sputtered-WO3 films by post-annealing in O2 ambient. we also have try a novel and very simple process for the thin films of WO3 by the LPD process. Adherent and conformal WO3 electrochromic films were prepared on ITO/glass from aqueous fluoride solution.

ABSTRACT SYNTHESIS AND CHARACTERIZATION OF THIOPHEN-3-YL ACETIC ACID 4-PYRROL-1-YL PHENYL ESTER AND ITS CONDUCTING POLYMERS Bing&ouml / l, Bahar M.Sc., Department of Chemistry Supervisor: Prof. Dr. Levent Toppare November 2003, 54 pages Thiophen-3-yl acetic acid 4-pyrrol-1-yl phenyl ester (TAPE) monomer was synthesized by the reaction of thiophene acetic acid with thionyl chloride, and further reaction of thiophen-3-yl-acetyl chloride with 4-pyrrol-1-yl phenol. Electrochemical behavior of this monomer (TAPE) was determined by cyclic voltammetry. Homopolymers were achieved both by using electrochemical and chemical polymerization techniques. Copolymers of TAPE in the presence of bithiophene and pyrrole were synthesized by potentiostatic electrochemical polymerization in acetonitrile-tetrabutylammonium tetrafluoroborate (TBAFB) solvent-electrolyte couple. The chemical structures were confirmed both by Nuclear Magnetic Resonance Spectroscopy (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). Differential Scanning Calorimetry (DSC) and Thermal Gravimetry Analysis (TGA) were used to examine the thermal behavior of synthesized conducting homopolymers and copolymers. The morphologies of the films were investigated by Scanning Electron Microscope (SEM). Two-probe technique was used to measure the conductivities of the samples. Moreover, investigations of electrochromic and spectroelectrochemical properties of poly(TAPE) and TAPE/BiTh copolymer were done. Keywords: Conducting copolymers, electrochromic properties

This thesis is a comparative study of nickel oxide based thin films for use as a counter electrode in a variable transmittance electrochromic device. Coatings have been prepared using anodic electrodeposition, colloidal precipitation and radio frequency (r.f.) sputtering. Systematic studies of the effect of deposition process parameters on optical and electrochromic properties of such films have been undertaken. Optimum conditions for the deposition of coatings deposited by colloidal and anodic deposition have been determined. A novel process for the colloidal deposition of electrochromic a-Ni(OH)2 coatings using a simple one dip process is reported. Also the electrochromic properties of coatings anodically deposited from aqueous solutions containing NiS04 and NH40H were improved by the addition of the non-ionic surfactant polyoxyethylene sorbitan monolaurate. Spectroscopic and electrochemical analytical techniques were used to identify the chemical composition of the coloured and bleached states. It was found using Fourier transform infra-red spectrophotometry (FTIR) that coatings deposited by anodic and colloidal deposition contained f3-Ni(OH)2 and a-Ni(OH)2 respectively in the as-deposited and transparent states. For coatings deposited by both techniques 13 or y-NiOOH was detected in the coloured state using FTIR. Using Raman spectroscopy, y-NiOOH was detected in the coloured state for coatings deposited by anodic deposition from solutions containing the additive polyoxyethylene sorbitan monolaurate. I3-Ni(OH)2 was also detected in the transparent state of r.f. sputtered coatings that were electrochemically cycled in 1M KOH(aq). Using cyclic voltammetry the oxidation of nickel hydroxide to the oxyhydroxide was detected during colouration for coatings produced using anodic electrodeposition, colloidal precipitation and r.f. sputtering (after cycling sputtered films for 1 hour in 1M KOH(aq)). This information has been compared for films prepared using the different deposition techniques to enable the respective colouration mechanisms to be elucidated. Prototype electrochromic devices have been constructed and their performances assessed. It can be concluded that nickel oxide based coatings can be used as suitable counter electrodes for hydrated electrochromic devices.

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Thesis (Ph.D.)--Tufts University, 1991. / Submitted to the Dept. of Electrical Engineering (Electro-Optics Option). Includes bibliographical references. Access restricted to members of the Tufts University community. Also available via the World Wide Web;