resumo
Ferroionic materials combine ferroelectric properties and spontaneous polarization with ionic phenomena of fast charge recombination and electrodic functionalities. In this paper, we propose the concept of tunable polarization in CeO2-delta (ceria) thin (5 nm) films induced by built-in remnant polarization of a BaTiO3 (BTO) ferroelectric thin film interface, which is buried under the ceria layer. Upward and downward fixed polarizations at the BTO thin film (10 nm) are achieved by the lattice termination engineering of the SrO or TiO2 terminated Nb:SrTiO3 (NSTO or STN) substrate. We find that the ceria layer punctually replicates the polarization of the BTO interface via a dynamic reconfiguration of its intrinsic defects, i.e., oxygen vacancies and small polarons. Tunable oxidative or reducing properties (redox) also arise at the surface from the built-in polarization. Opposite polarities at the ceria termination tune the chemo-physical dynamics toward water molecule adsorbates. The inversion of the surface potential leads to a modulation of the water adsorption-desorption equilibrium and water ionization (splitting) redox overpotentials within +/- 400 mV at room temperature, depending on the ceria termination's charges. Such tunability opens up the perspectives of using ferroionics for wireless electrochemically enhanced catalysis.
palavras-chave
THIN-FILMS; SURFACE; BATIO3; ENERGY; CHEMISTRY; CERIA; FERROELECTRICITY; DEPENDENCE; INTERFACES; STATES
categoria
Science & Technology - Other Topics; Materials Science
autores
Vasiljevic, M; Chiabrera, F; Alikin, D; Motti, F; Bergne, A; Zamudio-García, J; Qin, XP; Dagur, D; Yun, SH; Marrero-López, D; Vinai, G; Castelli, I; Kholkin, A; Esposito, V
nossos autores
Andrei Kholkin
Investigador Jubilado
Denis Alikin
Investigador AuxiliarProjectos
Piezoelectricity in 2D-materials: materials, modeling, and applications (Piezo2D)
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
agradecimentos
M.V. and F.C. contributed equally to this work. This research is supported by the MANTRA (Villum Experiment, grant no. 413 40412). The authors acknowledge Nini Pryds for the early conceptualization and valuable discussions. V.E. acknowledges the Danish Council for Independent Research Technology and Production Sciences for the DFF- Research Projects 2 (Grants No. 48293, 48592, and 1032-00261B) and partially the DEMETRA (M-ERA.NET project number 2118-00006B). M.V. acknowledges Elettra Sincrotrone Trieste for providing access to its synchrotron radiation facilities under Proposal No. 20230405 and for financial support under the IUS internal project. This work has been partially performed in the framework of the Nanoscience Foundry and Fine Analysis (NFFA-MUR Italy Progetti Internazionali) facility (https://www.trieste.nffa.eu/). M.V., D.A., A.K., and V.E. acknowledge support from the Horizon Europe Framework Programme (HORIZON-TMA-MSCA-SE), project No. 101131229, Piezoelectricity in 2D-materials: materials, modeling, and applications (PIEZO 2D). Part of this work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 (DOI 10.54499/UIDB/50011/2020), UIDP/50011/2020 (DOI 10.54499/UIDP/50011/2020), and LA/P/0006/2020 (DOI 10.54499/LA/P/0006/2020), financed by national funds through the FCT/MCTES (PIDDAC).