The past two decades have shown that the exploration of properties on the nanoscale can lead to substantially new insights regarding fundamental issues. The project research is based on the use of pulsed laser deposition (PLD) technique. The project deals with the preparation and characterization of the structure and conductivity of advanced epitaxial heterostructures of proton conducting oxides. The first step is to fabricate the nano-systems with control over the growth process at an atomic scale, leading to high quality epitaxial thin films and multilayers of proton-conducting oxides. Thinnia will contribute to the development of technologies for an environment-friendly energy production expecting to benefit the general society. The donor partner, University of Oslo (Norway), is a world-Ieader in oxide defect chemistry including thermodynamics, diffusion and mobility of defects, conductivity and permeability. Project promoter, the Catalan Institute of Nanotechnology, has worked extensively on photovoltaics, thermoelectrics, ferro-and flexo-electricity for energy harvesting and Li-ion batteries.
Summary of project results
This research proposal is oriented towards the understanding of fundamentals in nano-sized proton conducting oxide systems. The first step is to fabricate the nano-systems with control over the growth process at an atomic scale, leading to high quality epitaxial thin films and multilayers of proton-conducting oxides. We study the influence of pulsed laser deposition conditions in film microstructure, particularly at the interfacial region, and how strain and the presence of defects may influence the materials charge transport, as well as oxygen surface exchange properties. The application of these novel nanostructured devices in electrochemical devices (e.g. solid oxide fuel cells, gas separation membranes, gas sensors) is considered to be the key for the development of future energy technologies for the generation of more efficient and clean energy. We have investigated the influence of growth parameters of BZY thin films by PLD on a number of single crystal substrates and target materials to the functional properties of the films. BZY grows epitaxially on MgO (100), GSO (110), STO (100), NGO (110), and LAO (100), but not on sapphire ( ). The deposition conditions were studied in detail to reveal the influence the morphology, cell parameters and chemical composition on the films´ functional properties. We concluded that the oxygen partial pressure during film growth is the most determining. The BZY thin film protonic conductivity was optimised for films grown at 50 mtorr of O2, for both the Ni-free and 1% Ni-containing targets, reaching conductivity values and activation energies typical for bulk BZY, although they are lower than those reported by the highest conducting BZY thin films prepared in a similar manner. High temperature XRD shows that the expansion of epitaxial films behave different than bulk. BZY films deposited on MgO are special due to the fact that the film is under tensile strain at high temperature (during operation conditions) while it reverses into compressive strain below 300 ºC. Strong links via informal meetings with Prof. Norby (UiO) and Dr. Marie-Laure Fontaine (SINTEF) have taken place by e-mail and by the meetings in Oslo to configure a solid collaboration network between these institutions and ICN2. Several manuscripts have been submitted in high impact peer-reviewed journals and will be available to the public in due time, while oral and poster presentations have been carried out for both specialized and wider audiences.
Summary of bilateral results
The infrastructure at ICN2 and the expertise of the host institution researcher on thin films has made it possible to prepare and characterize the films, as expected. Besides the strong cooperation during the project and in order to be able to continue such joint research, partners have written and submitted a m-ERA.NET project called SURKINOX by the 10th of June 2015. The partners are SINTEF and University of Oslo (Norway), Universtity of Twente (The Netherlands) and ICN2. IT passed the 1st round to the 2nd round (deadline 10th of November) with very good score. The decision of this project will be published during January 2016 and would allow more intensive collaboration within the consortium partners. Additional projects are expected to be written when the suitable call is announced.