Berlin 2024 – scientific programme

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 23: Focus Session: Fermi level engineering of functional ceramics

KFM 23.2: Talk

Thursday, March 21, 2024, 10:00–10:20, E 124

Operando XPS Study with electrochemical cell setup — •Savita Chaoudhary, Pengcheng Hu, Binxiang Huang, Kim Alexander Creutz, Yue Liu, Gero Johannes Pickel, Vinit Agarwalla, Alexander Frebel, and Andreas Klein — Technical University of Darmstadt, Darmstadt, Germany

The change of the oxygen content in a material using an electrochemical cell is an important asset to understand the variation of the Fermi energy in materials, paving the way for Fermi level engineering as a versatile toolkit for designing a broad range of materials according to specific applications. The electrochemical cell is constructed by top and bottom electrodes deposited on an oxygen ion conducting electrolyte. The reduction or increase of the oxygen content in the electrodes by cathodic or anodic polarization, is accompanied by an increase or lowering of the Fermi energy, respectively. The latter can be monitored together with chemical changes of the sample if the electrochemical cell is operated in an X-ray photoelectron spectrometer. We will present experiments using Y-stabilized zirconia, Fe-doped SrTiO3, (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3(PMN-PT), Na1/2Bi1/2TiO3-BaTiO3 (NBT-BT) or (Pb,La)(Zr,Sn,Ti)O3 (PLZST) as electrolytes, and (Sn-doped) In2O3, SrFeO3-δ and Sr-doped LaCoO3-δ as electrode materials. The use of the setup to quantify the Fermi energies of charge transition levels in either the electrolyte or the electrode will be demonstrated.

Keywords: Operando XPS; Electrochemical cell; Electrode; Electrolyte; Fermi Engineering