23 August 1995 Electrochromism of W-oxide-based films: some theoretical and experimental results
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We survey some recent work related to electrochromic W-oxide-based thin films. The electronic structure of cubic (perovskite) WO3 and HWO3 was calculated from first principles. It was found, among other things, that hydroxide formation was energetically favored. Experimental studies were made on films prepared by reactive magnetron sputtering in Ar + O2 with and without CF4 addition and substrate bias. Structural studies by atomic force microscopy, x-ray diffraction, infrared reflectance spectroscopy, and Raman spectroscopy indicated that the electron bombardment associated with a positive substrate bias led to grain growth and partial crystallization while maintaining a high density of W equals O double bonds presumably on internal surfaces. Electrochemical and spectrophotometric measurements demonstrated, in particular, that tandem films -- with a thin protective layer of electron bombarded oxide covering a thicker oxyfluoride layer -- were able to combine rapid dynamics of the electrochromism with good durability. Oblique angle sputtering in Ar + O2 gave films whose microstructure comprised inclined columns, as seen from scanning electron microscopy. Pronounced angular selective transmittance was found to coexist with electrochromism.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Andris Azens, Andris Azens, A. Hjelm, A. Hjelm, David Le Bellac, David Le Bellac, Claes-Goeran Granqvist, Claes-Goeran Granqvist, Joanna Barczynska, Joanna Barczynska, E. Pentjuss, E. Pentjuss, J. Gabrusenoks, J. Gabrusenoks, J. M. Wills, J. M. Wills, } "Electrochromism of W-oxide-based films: some theoretical and experimental results", Proc. SPIE 2531, Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XIV, (23 August 1995); doi: 10.1117/12.217361; https://doi.org/10.1117/12.217361


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