AMaSiS 2018 Workshop: Abstracts

From semiconductor defect chemistry to electrochemistry – Challenges and insights

Mira Todorova, Suhyun Yoo, Sudarsan Surendralal, and Jörg Neugebauer

Max-Planck-Insitut für Eisenforschung, Düsseldorf

Electrochemistry plays a central role in a manifold of areas, e.g. electro-catalysis, corrosion, electroplating and others. The solid/liquid interface is central to each of them, thus optimising or suppressing a certain process will depend on our ability to influence the electrochemical reactions occurring at this interface. This requires identifying relevant processes at the microscale, but also understanding how they influence properties the macroscale.
Density functional theory (DFT) calculations are able to resolve processes at the microscopic scale and have proven immensely successful in providing understanding in many problems in materials science, complementing experimental information. Yet, a particular challenge to DFT modelling is the presence of different classes of materials (metal, semiconductor/insulator, liquid) within electrochemical systems, which have dissimilar characteristics and thus imposes different requirements on the investigational approaches.
To address these challenges we adapt concepts originally developed in the field of semiconductor physics to tackle problems in electrochemistry. We developed an approach which unifies and translates theoretical concepts of these two fields. This approach [1] is based on a fully grand-canonical description of both ions and electrons and utilises charged point defects as common fundamental motive of the various phases. It enables the characterisation of materials properties in electrochemical environment and facilitates comparison to experiment. Applying the approach to oxide semiconductors [2, 3, 4], enables us, e.g., to discuss the impact an electrochemical environment has on the electronic structure of a semiconducting electrode.