ISSN:
1862-0760
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Physik
Notizen:
Abstract Tungsten oxides are known to exhibit interesting electrochemical properties. Ion insertion (Li+, H+) within the oxide network is highly reversible. It leads to a blue coloration and WO3 thin films can be used as electrochromic layers in display devices or smart windows. Tungsten oxide thin films can be conveniently deposited from aqueous solutions of tungstic acid. However polytungstic acids are not stable and tend to precipitate into hydrated tungsten oxide WO3⋅2H2O. The condensation of polytungstic species can be chemically controlled by adding foreign ions in the solution. Precipitation is no more observed in the presence of H2O2. Peroxopolytungstic acids are formed in which chelating [O2]2− ligands prevent the formation of an oxide network. Such solutions are specially convenient for the deposition of optically transparent thin films. Mixed oxides WO3-MoO3 are obtained when condensation is performed in the presence of Mo6+ cations. This paper shows how the condensation of tungstic acid can be chemically controlled and describes the electrochemical properties of the films deposited from such solutions.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF02375531
