Charge exchange dynamics of ions for structural studies

Thin material layers and especially 2D materials are of great importance for a variety of industrial applications. A new class of ultrathin sheets, based on organic molecular networks, is of particular interest in fuel cell applications, for osmotic power devices, and for water desalination. Atoms are arranged only in a short-range ordered fashion in these materials, i.e. they appear randomly ordered on longer distances. Details of the atomic structure define the chemical and mechanical properties of these sheets. However, the use of conventional microscopy techniques to determine the atomic structure is limited, because electron microscopy leads to changes of the materials during measurement, and scanning probe microscopy yields reliable results only at very low temperatures. In this German-Austrian research project with 3 partners, we will develop an entirely new method for structural investigation of short-range ordered organic molecular nanosheets. Our method is based on the interaction of ion beams with matter. Electrical charge is exchanged between the ion and target atoms during transmission of the ions through the material. The amount of charge exchange is determined by the distance at which the ion passes the atoms. In addition, ions are slowed down when they pass the material. The measurement of the charge of the ion after transmission, the energy loss, and the deflection angle, yields the information about the atomic structure. Especially slow heavy ions in high charge states are suitable for the task, because they experience large charge exchange. The project will be conducted at TU Wien, the University Bielefeld, and the Friedrich-Schiller- Universität Jena. All three groups contribute with unique knowledge and experience to the project. Only the collaboration of the partners and the synergetic combination of available experimental methods at the different sites allows the determination of the structure of short- range ordered organic molecular nanosheets for the first time.