Events

17 January

Microstructure and Ferroelectricity Methylammonium Lead Iodide Perovskite Solar Cells

Thursday 17 January 2019, 12:00pm

ICN2 Seminar Hall, ICN2 Building, UAB

By Dr. Alexander Colsmann, Head of Organic Photovoltaics Group, Lichttechnisches Institut , Karlsruhe Institute of Technology (KIT), Germany

Short Abstract: The microstructure of absorber layers is pivotally important for all thin-film solar technologies. Despite its unprecedented performance development in recent years, little is known about the microstructure of metal-halide perovskites and its effect on the macroscopic device performance. Among the remarkable properties of MAPbI3 is its ferroelectricity. If the ferroelectric polarization influences the charge carrier recombination and transport, as was predicted by simulations, then the orientation and shape of polarized domains within grains would directly influence the device performance. In turn, this renders engineering of the grain orientation and size a pivotal parameter for the optimization of perovskite solar cells which is not yet commonly investigated in most perovskite solar cell studies.

In this work, we report on a combined electron backscattered diffraction (EBSD), piezo-response force microscopy (PFM) and kelvin probe force microscopy (KPFM) study to spatially resolve and correlate the crystal orientation and ferroelectric polarization with sub-micrometer resolution. These tools are indispensable for the future relation of the microscopic structure to the optoelectronic properties of perovskite devices as they allow to monitor device optimization and to understand fundamental processes of perovskite solar cells. Therefore, we expect EBSD and PFM to become the most often employed characterization techniques in the future for the correlation of microscopic structure and macroscopic device performance. Their strong correlation allows to draw conclusions about the microstructure from ferroelectric features and, likewise, to derive the ferroelectric polarization from crystallographic observations. Understanding the microstructure would not least be the key to future ab-initio engineering of new (non-toxic) and highly efficient perovskite solar cells.

References

[1] H. Röhm, T. Leonhard, M.J. Hoffmann, A. Colsmann, Energy Environ. Sci. (2017), 10, 950-955.

[2] D. Rossi, A. Pecchia, M. Auf der Maur, T. Leonhard, H. Röhm, M.J. Hoffmann, A. Colsmann, A. Di Carlo, Nano Energy (2018), 48, 20-26.

[3] T. Leonhard, A. Schulz, H. Röhm, S. Wagner, F. Altermann, W. Rheinheimer, M.J. Hoffmann, A. Colsmann, submitted.

Hosted by: CSIC Research Scientist Mónica Lira-Cantú, Nanostructured Materials for Photovoltaic Energy Group Leader