Tungsten oxide electrochromic windows

A general schematic for a smart window is shown in Figure 13.10. This device is, quite literally, two chemically modified electrodes sandwiched together. In this case, the films coating the electrode surfaces are electrochromic materials. A polymer electrolyte, analogous to that used in the fuel cell discussed earlier, is sandwiched between these two electrochromic material-coated electrodes. In a recent example of this concept by Habib and Maheswari of General Motors Research Laboratories [94], the cathodic electrochromic material was a tungsten oxide and the cathodic electrochromic material was the material Prussian blue, discussed in Section II of this chapter. It seems likely that electrochromic cells will soon find their way into the commercial marketplace. 

The preparation and characterization of vanadium oxide (V2O5) modified tungsten oxide (WO3) films by pulse laser deposition were recently examined [61]. Tungsten oxide coatings are used in many electro-optical applications including catalysts, solar cell windows, electrochromic and gasochromic devices, optical memory and... 

Problem 5.5. A vacuum reactor is used to synthesize WO3 nanoparticles for use in an electrochromic window device. To create the WO3 nanoparticles, a tungsten (W) metal filament 1.0 mm in diameter and 10 cm long is heated to 2200 °C in a vacuum with a trace pressure of oxygen gas. Assuming all of the W evaporating from the surface of the filament is rapidly and completely oxidized to WO3, determine the maximum rate of production of WO3 from this reactor (g/s). The equilibrium vapor pressure of W at 2200 °C is approximately 10 atm. 

K. Friestad, G. Hagen, S. Panero, and B. Scrosati [1997] Transmission Spectra and Electrochemical Impedance Analysis of Polyaniline, Prussian Blue and Tungsten Oxide with Incorporated Nickel in Electrochromic Windows, Electrochem. Soc. Proc. 96, 353-368. 

G.A. Niklasson and C.G. Granqvist (2007) J. Mater. Chem., vol. 17, p. 127 - Electrochromics for smart windows Thin films of tungsten oxide and nickel oxide, and devices based on these . 

Granqvist C.G. Electrochromics and smart windows. Solid State Ion. 1993 60(1-3) 213-214 Granqvist C.G. Handbook of Inorganic Electrochromic Materials, Elsevier, Amsterdam, 1995 Granqvist C.G., Electrochromic tungsten oxide films Review of progress 1993-1998. Sol. Energy Mater. Sol. Cells 2000 60 201-262... 

Jelle, B. P. and Hagen, G., Transmission spectra of an electrochromic window based on polyaniline, Prussian blue and tungsten oxide, J. Electrochem. Soc., 140, 3560, 1993. 

Inorganic oxides as well as electroactive polymers are known for their electrochromic behavior. Tungsten trioxide - has been utilized in electrochromic windows. Among electroactive polymers polyaniline - and polythiophenes have been studied most extensively as electrochromic solids. 

PASSERINI, s., SCROSATI, B., HERMANN, V., et ol.. Laminated electrochromic windows based on nickel oxide, tungsten oxide, and gel electrolytes,/. Electrochem. Soc., 1994,141,1025-8. 

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