Browsing by Author "Zambrano-Mera, Dario"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    In-situ hydrogenated V2O5 thin films: Study of the structural dynamics and their behavior as Li-ion batteries cathode
    (2024) Briceno, Mackarena; Villarroel, Roberto; Zambrano-Mera, Dario; Fernandez, Juan; Flores, Marcos; Rojas-Saez, Nicols; Lisoni, Judit; Hevia, Samuel; Espinoza-Gonzalez, Rodrigo
    This investigation focuses on a one-step preparation method to produce hydrogenated V2O5 thin films by controlling the atmosphere of the DC reactive magnetron sputtering process. An increasing hydrogen flux during the film deposition promotes the formation of defects such as oxygen vacancies and hydroxyl sites in the oxide matrix. The hydrogenated samples were tested as cathodes in Li-ion batteries and exhibited lower charge capacities but superior stability to cycling compared to pristine V2O5 film. These results pave the way to prepare hydrogenated transition metal oxide thin films by a simple route without further thermal procedures and affordable conditions.
  • No Thumbnail Available
    Item
    Structural and photoelectrochemical dynamics of in-situ hydrogenated anatase TiO2 thin films grown by DC reactive magnetron sputtering
    (2023) Villarroel, Roberto; Zambrano-Mera, Dario; Espinoza-Gonzalez, Rodrigo; Paredes-Gil, Katherine; Pantaleone, Stefano; Ballesteros, Luis; Oskam, Gerko; Garcia-Merino, Jose A.; Hevia, Samuel A.; Gonzalez-Moraga, Guillermo
    Hydrogenation has become one of the most used strategies to improve the photoactive properties of titanium dioxide nanomaterials, n-TiO2. In order to obtain more information about the hydrogenated process on anatase TiO2 thin films and the improvement of the photoactivity of this material, we report a study on the structural changes of hydrogenated anatase thin films produced by direct-current reactive magnetron sputtering. In the first stage of the hydrogenation process, the obtained polycrystalline anatase films present an increment of the {0 0 1} facet according to the amount of hydrogen used in the plasma reaction. At higher hydrogen concentrations, amorphous and rutile phases start to appear. The photoactivity of the hydrogenated anatase samples, H:TiO2, presents a redshift of the photoelectrochemical onset and an increase of the reactivity in the UV region. Both results were experimentally and theoretically related to the formation of defects such as oxygen vacancies and TiH/Ti-OH bonds at the surface of the hydrogenated thin films.