Orthorhombic WO3?0.33H2O can be applied for the production of electrochromic film. Experts used urea as a structure directing agent to grow WO3 nanostructured films under hydrothermal conditions with and without crystal seed layer. The XRD patterns were observed and found:
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The diffraction peaks of the WO3 electrochromic films prepared as shown in the above figure are consistent with the diffraction peaks of the respective crystal faces of the standard card, JCPDSno. 54-1012. This indicates that the prepared films are all orthorhombic WO3?0.33H2O, and the crystal seed layer does not affect the crystal phase of the prepared film. While the film prepared under the condition of no crystal seed layer has different growth orientation on the (020) crystal plane compared with the seed-assisted preparation of the film. It is mainly because the crystal seed layer can not only provide a growth site for the film material, but also has a structure directing effect during film growth and affects electrochromic properties.
