Interfaces, charge-transfer and non-adiabatic processes and their exploitation in a frequency-tunable tribogenerator

Doctoral position in the Area of Triboelectricity

Triboelectric effects in functional material systems enable the implementation of novel design concepts for energy harvesting. The corresponding project “TriboGen” will perform basic research on the design of triboelectric generators and the triboelectric effect as such, to answer the following questions:

• What is the best combination of triboelectric materials?
• What is the influence of chemical or physical surface modifications on the triboelectric effect?
• How can the triboelectric effect be characterized best?
• How to design an optimal resonant tribogenerator?
• How to build a frequency-self-tunable resonant tribogenerator?
• How to do an optimal charge extraction from tribogenerators?

The candidate will mostly focus on the design and fabrication of triboelectric generators and on test set-ups for characterizing triboelectric materials. The other questions above are addressed together with her/him in the team of scientists working in the project on modeling and characterization of triboelectric materials. Applicants should have a diploma or master's degree in physics, electrical engineering, mechanical engineering, microsystems technology or similar. Furthermore, eagerness to acquire personal skills and further knowledge are mandatory as well as good self-organization and ability to work independently, although under supervision.

Applications are closed as of Mai 31^st 2019. We expect to fill this position by July 15^th 2019.The position will be supervised by Prof. Dr. Peter Woias.

Doctoral position in the area of charge transfer at interfaces

Charge transfer at interfaces is a central topic inthe project Interfaces, charge-transfer and non-adiabatic processes and their exploitation in a frequency-tunable tribogenerator. We will employ electronic structure calculations to investigate the relevant interfacial transport properties. The main topic will be the elucidation of the working principles of tribogenerators, where the calculations shall unravel the electrification of the contacting interfaces. Different hypotheses for the origins of charge separation will be explored within electronic structure calculations in the ground-state of the material as well as in excited state investigations.

Charge transfer over complex interfaces is also of high importance in the project Inorganic and Organic SolStore, where solar energy conversion and storage will be combined within the same material. Here, junctions between organic and inorganic/metallic and semi-metallic regions will determine the overall device performance. Their structural, electronic and optical properties will be investigated with density-functional theory. Tuning of molecular properties e. g. through optimized Fermi level alignment will reveal the optimal choice of the organic phases and in this way guide their synthesis. The effect of different anchor groups and substituents will be screened. Predicted optical- and electrochemical properties will be contrasted with the experimental observations of WPO1 to obtain insights into the origins of the spectral features observed.

Applicants should have a M.Sc. in physics, chemistry, materials science or related disciplines. Knowledge of a scientific programming language (e.g. Python) is required and experience with high performance computing is a plus but not mandatory. Willingness to integrate into larger software development projects and to work closely with experimentalists is mandatory

Applications are closed as of March 12^th 2019. We expect to fill this position as soon as possible.The position will be supervised by Prof. Dr. Michael Moseler and PD Dr. Michael Walter.

Doctoral position in the area of Nanotribology

Triboelectric effects in functional material systems enable the implementation of novel design concepts for energy harvesting. Thus, the understanding of the fundamentals of the triboelectric effect at free interfaces is crucial, in particular for organic material or combinations of organic materials with metal. This will lead to optimization of charge separation properties, in particular for nano- and/or micro-structuring of surface topologies. In this project you will use AFM based techniques to characterize surfaces and surface charges before and after contacting experiments. This will be done in a unique combination of AFM-based imaging, AFM-based determination of local elastic moduli, AFM-based force spectroscopy and Kelvin Probe Force Microscopy.

Applicants should have a master's degree in physics, biophysics, physical chemistry or similar. Furthermore, eagerness to learn the different AFM applications and to acquire further knowledge as well as good self-organization and ability to work independently are required. 

The position will be supervised by Prof. Dr. Thorsten Hugel.

Applications are closed as of January 31^st 2019.

Doctoral position in the Area of Solid Mechanics for Triboelectricity and Metamaterials

Mechanical processes are essential for living materials systems. In this project, you will develop and apply numerical methods to gain insights into the mechanics of triboelectric nanogenerators and metamaterials. For both systems, the mechanical response is essential for the system’s function. In triboelectric generators, rough or patterned surfaces make contact and the mechanics of the interface determines contact area and stiffness and hence the charging efficiency. For metamaterials, the structural design of the individual unit cell determines the constitutive macroscopic response that can be designed in silico. Both problems will be attacked with the help of spectral solvers that allow for efficient solution of the underlying physical problem.

The candidate is expected to carry out this project in close collaboration with experimental efforts. Applicants should have a master's degree in microsystems engineering, mechanical engineering, materials science, physics or related disciplines. Basic knowledge of a scientific programming language (Python, C++, Fortran) is required. Willingness to integrate into larger software development projects and to work closely with experimentalists is mandatory.

This position will be split between the project Interfaces, charge-transfer and non-adiabatic processes and their exploitation in a frequency-tunable tribogenerator and the project Logic Self-Reporting Mechano-Adaptive Metamaterials.

Applications are closed as of January 15^th 2019. The position will be supervised by Prof. Dr. Lars Pastewka.