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Physical chemistry of solids connects solid state physics and solid state chemistry. In solid state physics the electronic properties of solids and their application or use play the major role. In solid state chemistry traditionally the synthesis and the structural characterisation dominate.

The aim of physical chemistry of solids is the understanding of chemical reactions in and of solids – i. e. the reactivity of solids – by the use of physical methods and concepts (quantum chemistry, spectroscopy, solid state physics, etc.). The most prominent problems and fields within physical chemistry of solids are today:

  • Corrosion
  • Heterogeneous catalysis and surface chemistry
  • Energy storage/-transformation (fuel cells, batteries, photoelectrochemistry, …)
  • Chemical sensors
  • Information storage by redox switching
  • Transport phenomena (diffusion, migration, permeation, …)
  • Size effects (nanoscaled materials)
  • Degradation of functional materials
  • ...

A key phenomenon in numerous fields and a necessary precondition für the chemical reactivity of solids is atomic mobility – in other words diffusion. The understanding and control of atomic mobility is – both on the atomic scale (dynamics) as also on the macroscopic scale (transport) –a serious constraint for the development of many future technologies. It forms an important element of nearly all projects of our research group.

Our research is focused on physical chemistry of solids in general, with a strong interest in materials for electrochemical energy technologies, their reactions and their long term stability. Driven by the increasing importance of electrochemical energy transformation and storage this topic has expanded in our group during the last years. Still our primary concern is fundamental science, but recently we also started applied research (e. g. projects with BASF SE or with Evonik/Degussa AG). We concentrate on inorganic functional materials, their controlled synthesis by physicochemical methods (e. g. pulsed laser deposition), their modification by doping or surface design, the understanding of their properties on the basis of structure and defects and their stability under the influence of external forces. In view of the desired long operation time of modern energy transformers and storages the study of materials stability and degradation gains importance – in particular in the case of nanostructured materials. Since a few years we also investigate electrochemical applications of ionic liquids, e. g. for the deposition of nanoscale particles.

In essence, all our projects center on the interplay of atomic or ionic motion in inorganic (non-metallic) solids with external driving forces – like chemical or electrical potential gradients, temperature gradients or magnetic fields. A typical problem is the controlled application of electric fields for the manipulation or modification of ion- and electron-conducting solids. Materials or compounds under consideration are typically ion- or mixed conducting oxides, oxinitrides, chalcogenides and halides.

Research in "materials for energy/sensor technologies"

The study of non-stoichiometric and usually ion- and electron-conducting solids is a long term center of our work. Charge and mass transport under different conditions (in electric fields, in chemical potential gradients, temperature gradients or magnetic fields), the influence of equilibrium and non-equilibrium defects (interfaces, dislocations), solid state reactions and their control are examples for more specific subjects. Materials under investigation are relatively stable ionic compounds, e. g. halides, oxides and chalcogenides, nitrides and oxinitrides of transition metals – from simple binary phases to complex multinary phases or dispersions.

Research in "electrode kinetics of solid electrolytes"

The electrode kinetics of solid electrolytes plays a crucial role in various solid state electrochemical applications. Notwithstanding the electrode kinetics of even simple systems is only insufficiently investigated and understood. For this reason we study the kinetics of two important model cases: The metal dissolution and deposition on cation-conducting solid electrolytes, and the gas electrodes on oxygen ion-conducting solid electrolytes. Recently we started to investigate the kinetics of less usual gases (e. g. nitrogen or ammonia). As methods we apply conventional electrochemical techniques but also microscopic and micro-spectroscopic in situ techniques.

Research in "electrochemical surface control"

Main aim of this topic is to understand the influence of electric polarization on surface properties of functional materials. Currently we concentrate on projects in heterogeneous catalysis (NEMCA/EPOC), but new projects on other surface phenomena are in preparation.

Research in "electrochemistry and plasmaphysics"

The combination of plasma chemistry and electrochemistry is the long term aim of different projects in cooperation with plasma physicists. We focus on the characterisation and understanding of reactions at interfaces between “gaseous” conductors (plasmas) and solid or liquid ionic conductors.

Research in "Bioanalytic using TOF-SIMS"

By using Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) it is possible to obtain chemical information of biological samples with a high lateral resolution. Within the Sonderforschungsbereich TRR79 we investigate different questions concerning the incorpoartion behaviour of new implant materials for osteoporosis patients. We are interested in the Investigation of bone cross sections and in the cell-implant interaction.

Scientific Equipment and Investigation Methods

This page will contain information about the scientific equipment of the Janek group and which investigations methods can be used. At the moment this information is only accessible in the German part of this homepage. If you need further information, please contact the secratary of Prof. Janek by clicking on "Office RG Prof. Janek" on the right site of this page.

Scientific collaborations

Members of the research group participate in a number of national and international collaborations. Our most important partners are listed here.

Future questions, problems and tasks

This page will be soon available in English.