Spectroscopy

To avoid effects caused by quenching and/or incomplete freezing-in of defect chemical reactions, in-situ spectroscopic methods (elevated T, adjusted component activity (pO₂, pH₂O etc)) are preferable. Spectroscopic methods with spatial resolution for investigation of transport processes are also in the focus.

• Space resolved optical spectroscopy -> kinetics of stoichiometry change

  Denk, F. Noll, and J. Maier: In-situ Profiles of Oxygen Diffusion in SrTiO₃: Bulk Behavior and Boundary Effects Journal of the American Ceramic Society 80(2), 279–285 (1997). DOI:10.1111/j.1151-2916.1997.tb02827.x

• Nuclear magnetic resonance -> proton transport in polymers

  M. Schuster, T. Rager, A. Noda, K. D. Kreuer, and J. Maier: About the Choice of the Protogenic Group in PEM Separator Materials for Intermediate Temperature, Low Humidity Operation: A Critical Comparison of Sulfonic Acid, Phosphonic Acid and Imidazole Functionalized Model Compounds
  Fuel Cells 5(3), 355–365 (2005). DOI: 10.1002/fuce.200400059

• Electron paramagnetic resonance -> in-situ measurement of defect concentrations

  R. Merkle and J. Maier: Defect association in acceptor-doped SrTiO₃: case study for Fe_Ti'V_O ^.. and Mn_Ti''V_O  ^..
  Physical Chemistry Chemical Physics 5(11), 2297–2303 (2003).
  DOI: 10.1039/b300205p

• Oxygen isotope exchange/SIMS -> diffusion / surface reaction kinetics

  M. Leonhardt, R. A. De Souza, J. Claus, and J. Maier: Surface Kinetics of Oxygen Incorporation into SrTiO₃ Journal of The Electrochemical Society 149(2), J19–J26 (2002). DOI: 10.1149/1.1430723

• X-ray absorption spectroscopy -> local structure information

  M. Vracar, A. Kuzmin, R. Merkle, J. Purans, E. A. Kotomin, J. Maier, and O. Mathon
  Jahn-Teller distortion around Fe⁴⁺ in Sr(Fe_xTi_1-x)O_3-δ from x-ray absorption spectroscopy, x-ray diffraction, and vibrational spectroscopy Physical Review B 76(17), 174107 (1–12) (2007). DOI:10.1103/PhysRevB.76.174107

• Analysis of electrochemical impedance spectroscopy of hybrid perovskite device
• Ion transport and photo-induced phase instability in mixed halide perovskites