Coevaporated perovskite thin films and solar cells: defect spectroscopy and device analysis

Supervised by Thomas Unold, Thomas Dittrich and Dieter Neher

 

Hybrid organometal-halide perovskite solar cells recently have shown very high conversion efficiencies exceeding 17%. This new class of solar cell materials can be synthesized either by solution chemistry or by co-evaporation in a vacuum environment.  Although the best performing perovskite solar cells so far have been obtained via the wet chemistry approach, the vacuum evaporation promises a much more homogeneous layer morphology and in principle allows for more control of the deposition and crystallization processes, in particular the substitution of elements, such as the  lead halides which are currently used in the highest efficiency devices.  As the role of bulk and interface defects in hybrid perovskite solar cells is still unclear at the moment, a fundamental understanding of recombination processes will become increasingly important as the device efficiencies reported start to approach 20%. The aim of this Ph.D. project is to prepare homogeneous hybrid perovskite absorber layers for solar cells by co-evaporation, and investigate the defect physics of these materials in dependence of the material composition and preparation conditions.  This will include the investigation of bulk defects as well as surface defects by various optoelectronic characterization techniques, and determining their influence on the performance of highly efficient perovskite-based solar cells.

 

Applicants interested in this project should have a good knowledge of solid state physics and be  interested in hands-on experimental work employing different state-of-the-art spectroscopic and solar cell characterization techniques.

Corresponding student

David Diering