Microstructure and properties of sol-gel deposited WO3 coatings for large area electrochromic windows

Cronin, John P.; Tarico, Daniel J.; Tonazzi, Juan Carlos López; Agrawal, Anoop; Kennedy, S. R.

doi:10.1016/0927-0248(93)90096-l

Cited by 87 publications

(27 citation statements)

References 23 publications

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“…Films of such oxide are usually prepared by vacuum evaporation [11 to 13], spray deposition coating [14,15], rf sputtering from compressed powder WO 3 [16,17] or a metallic target [18,19], dc reactive sputtering [20], and sol±gel processes [21,22]. The influences of the sputtering gas pressure and constituents as well as the substrate temperature and input power on the film structure and electrochromic properties have been intensively studied [20,23,24].…”

Section: Introductionmentioning

confidence: 99%

Preparation and Properties of Electrochemically Deposited Tungsten Oxide Films

Hutchins

Kamel

El-Kadry

et al. 1999

phys. stat. sol. (a)

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Tungsten oxide films of thicknesses 1095 nm have been cathodically deposited onto ITO coated glass substrates kept at room temperature, at a rate of 13 nm/min. The electrolyte solution has been prepared by adding 0.025 M tungsten (dissolved in 30% H2O2) to 0.25 M H2SO4. XRD observations showed that all films are amorphous. The film resistivity at room temperature was found to be 9 × 106 Ω cm, and from the resistivity–temperature dependence, the thermal activation energy was obtained as 0.29 eV. The refractive index, n, and the extinction coefficient, k, have been computed from the corrected transmittance and reflectance over the spectral range 400 to 800 nm. Absorption versus photon energy curves give an indirect transition with optical energy gap of 3.25 and 3.36 eV for the as‐deposited and coloured states, respectively. The electrochromic properties of the prepared films have been investigated in situ and both solar transmittance and optical density have been evaluated in the coloured and bleached states. The electrochemical coloration and bleaching were performed in an electrolyte of 0.4 M H2SO4 solution. The coloration efficiency has been evaluated as 50 cm2/C at λ = 600 nm, which is comparable with the results obtained from films prepared by other methods.

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Section: Introductionmentioning

confidence: 99%

Preparation and Properties of Electrochemically Deposited Tungsten Oxide Films

Hutchins

Kamel

El-Kadry

et al. 1999

phys. stat. sol. (a)

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“…[1][2][3] Coatings have been produced by a wide variety of techniques including solgel, [4][5][6] spin-coating, [7] electrochemical deposition, [8] vacuum physical vapour deposition (PVD), [9][10][11][12][13] thermal chemical vapour deposition (CVD) [14,15] and spray pyrolysis. [16][17][18] Solution methods are widely used but can result in film structural and durability constraints.…”

Section: Introductionmentioning

confidence: 99%

Growth of Thin Films of Molybdenum and Tungsten Oxides by Combustion CVD Using Aqueous Precursor Solutions

Davis

Benito

Sheel

et al. 2004

Chemical Vapor Deposition

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Using combustion chemical vapour deposition, layers of molybdenum and tungsten oxides have been deposited on glass and silicon at low temperatures. Inexpensive ammonium salts of molybdate and metatungstate ions were used as precursors and were delivered to the coating flame as an aqueous solution using a nebuliser. The resulting films were analysed by scanning electron microscopy (SEM), energy dispersive analysis of X-rays (EDAX), Rutherford backscattering (RBS), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD).These indicate that the films are continuous, moderately smooth and consist of amorphous, disordered molybdenum and tungsten trioxides.

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“…For example, in tungsten oxide, oxygen content is important for reversibly intercalating lithium ions [65], and is also important for charge capacity [66]. Since in the sol-gel method the coatings are given a heat treatment after deposition, one can easily incorporate oxygenating additives and/or provide environmental and heat conditions in this step to attain the desired stoichiometry [67].…”

Section: Deposition Of the Coatings Of The Required Thickness And Micmentioning

confidence: 99%

“…Controlling porosity using sol-gel technology is much easier, as one can incorporate materials (also called molecular templates) in the coating solution; such materials include oxalic acid and polyethylene glycol [60][61][62][63][64]. The templates can be removed during subsequent coatings processing to leave a porous structure.…”

Section: Deposition Of the Coatings Of The Required Thickness And Micmentioning

confidence: 99%

The Merits of Sol-Gel Processing for Electrochromic Windows: A Commercial Perspective

Agrawal

Cronin

2012

Sol-Gel Processing for Conventional and Alternative Energy

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Electrochromic windows are reversible electrochemical devices. For architectural windows, typical electrochromic device structures comprise of several layers of coatings, where oxidation and reduction of electrode coatings result in actively controllable optical properties by application of electrical potential. These windows reduce the energy cost of a building envelope by dynamically changing the solar transmission through the windows which are used to optimize both the lighting costs and thermal gains with changing outdoor conditions. Commercial electrochromic windows are now becoming available; however, to obtain broader market acceptance the cost/benefit ratio of these windows must be improved. The windows being introduced into the marketplace do not use sol-gel technology in their manufacturing process. Judicious use of solgel technology can assist in obtaining a more favorable cost/benefit ratio. Sol-gel processes offer the opportunity of making the cost attractive, given the unique aspects of the coatings used in this application, which include multiple metal oxide compositions, significant thickness, microstructural requirements, incorporation of mobile ions and the ability to effectively use low-cost transparent conductors.

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Microstructure and properties of sol-gel deposited WO3 coatings for large area electrochromic windows

Cited by 87 publications

References 23 publications

Preparation and Properties of Electrochemically Deposited Tungsten Oxide Films

Preparation and Properties of Electrochemically Deposited Tungsten Oxide Films

Growth of Thin Films of Molybdenum and Tungsten Oxides by Combustion CVD Using Aqueous Precursor Solutions

The Merits of Sol-Gel Processing for Electrochromic Windows: A Commercial Perspective

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