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2018-09-26 - Colloque/Présentation - poster - Allemand - page(s)

Panepinto Adriano , Cormier Pierre-Antoine, Michiels Matthieu , Bittencourt Carla , Snyders Rony , "Anatase-rutile mixed and nanostructured TiO2 thin films by DC and high power impulse magnetron sputtering at glancing angle" in Materials Science and Engineering Congress, Darmstadt, Germany, 2018

  • Codes CREF : Chimie (DI1300)
  • Unités de recherche UMONS : Chimie des interactions plasma-surface (S882)
  • Instituts UMONS : Institut de Recherche en Science et Ingénierie des Matériaux (Matériaux)

Abstract(s) :

(Anglais) Nowadays, anatase-rutile core shell structures are well recognized as highly efficient for TiO2 based catalysts or photoelectrodes of the dye-sensitized solar cells (DSSCs). In particular, for a DSSC the thin layer of rutile covering the core anatase column would be benefit to the device performance by promoting the charge transfer between the nanostructured photoanode and the sensitizer. In this work, we therefore propose to synthesize such nanostructured TiO2 thin films by reactive magnetron sputtering at glancing angle modulating the power applying mode. Pure anatase and well separated columns are first synthesized in DC mode, and then high pulse peak power is applied to the target (high power impulse magnetron sputtering – HiPIMS) to cover the columns by a thin layer of rutile. The latter technique is in fact well-known to improve the energy brought to the growing film which is a key parameter to successfully obtain the high temperature TiO2 phase, i.e. rutile. The peak current, the frequency and the pulse width are optimized in order to control the crystalline structure and the thickness of the rutile top layer. Scanning Electron Microscopy cross section views of the synthesized films clearly evidence that even if the film if collides by high energetic particles creating during the HiPIMS process the nanostructure is kept. Grazing Incidence X-Ray Diffraction also reveal the presence of both anatase and rutile in the films. The evolution of the main anatase and rutile diffraction peaks with the X-Ray incidence angle would indicate that the rutile is concentrated at the top surface of the material. Further characterization of the crystalline structure interface has been performed by a Transmission Electron Microscopy (TEM) mapping with a HAADF detector and confirm the latter hypothesis.