Abstract
WO3 films prepared under different conditions (evaporation, reactive sputtering and spraying of aqueous solutions of metatungstic acid) differ by orders of magnitude in their electrochromic sensitivity. Diffuse X-ray studies show the evaporated and sputtered films to be amorphous and to consists of a disordered network of corner sharing WO6 octahedra. Sprayed films have different degrees of crystallinity depending on spraying conditions. From differential scanning calorimetry we conclude that the crystal water present in most films strongly affects the local order of the corner sharing octahedra. We find that crystal water not only provides a high ionic conductivity which is conditional for a fast electrochromic reaction but also stabilises electrocatalytically active surface sites for fast hydrogen or Li exchange with the adjacent electrolyte.
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References
For a review on electrochromic materials and their properties see papers by J.Bruinink, I.F.Chang, H.R.Zeller: InNon Emissive Electrooptic Displays Brown Boveri Symposium Series, ed. by A. R.Kmetz and F.K.v.Willisen (Plenum Press, London 1976)
S.K.Deb: Phil. Mag.27, 801 (1973)
J.H.Schulman, W.D.Compton:Color Centers in Solids (Pergamon Press, London 1962)
I.F.Chang, W.E.Howard: IEEE Conf. on Display Devices and Systems (1974) p. 148
I.F.Chang, B.L.Gilbert, T.I.Sun: J. Electrochem. Soc.122, 955 (1975)
A survey of the patent literature is given in the paper by Chang in [1]
J.H.McGee, W.E.Kramer, H.N.Hersh: SID Int. Symp. Digest6, 50 (1975)
V.Wittwer: 5. Freiburger Arbeitstagung Flüssigkristalle, Inst. Angew. Festkörperphysik Freiburg, FRG (1975) p. 65
B.W.Faughnan, R.S.Crandall, P.M.Heyman: RCA Review36, 177 (1975)
R.Hurditch: Electronics Lett.11, 142 (1975)
See, for instance; R.S.Crandall, B.W.Faughnan: Appl. Phys. Lett.28, 95 (1976) and references cited therein
N.S.Hush: Prog. Inorg. Chem.8, 391 (1967)
P.Hagenmüller: Progr. Solid State Chem.5, 71 (1971)
M.B.Robin, P.Day: Adv. Inorg. Chem. and Radiochem.10, 247 (1967)
D.L.Kepert: Progr. Inorg. Chem.4, 199 (1962)
M.Kobale, H.P.Lorenz: in [8]
See, for instance, A.D.Franklin: J. Amer. Cer. Soc.58, 465 (1975)
Modern Electrochemistry, ed. by J.O'M.Bockris, A.K.N.Reddy (Plenum Press, New York 1970)
See, for instance, R.F.Kruth:Handbook of X-Rays, ed. by E.F.Kaelble (McGraw Hill, New York 1967) Ch. 22
H.Bräkken: Z. Krist.78, 484 (1931)
W.Biltz, G.A.Lehrer, K.Meisel: Nachr. Ges. Wiss. Göttingen, Math. Phys. Klasse 191 (1931)
See, for instance,Amorphous and Liquid Semiconductors, ed. by J.Tauc (Plenum Press, London, New York 1974)
N.J.Shevchik, W.Paul: J. Non-Cryst. Solids8–10, 381 (1972)
O.Glemser, R.v.Haeseler: Z. allg. anorg. Chem.316, 169 (1962)
J.E.Benson, H.W.Kohn, M.Boudart: J. Catalysis5, 307 (1966)