Probing the occupied and unoccupied density of states of hybrid Perovskites

In recent years, the interest in hybrid organic - inorganic perovskites rose at a rapid pace due to their tremendous success in the field of photovoltaics. In addition to the thin film properties of the active layer, the performance of optoelectronic devices strongly depends on the appropriate energetic alignment between the active- and adjacent layers. In order to choose adequate transport materials for the increasingly complex hybrid perovskite compositions in a non-trial-and-error fashion, it is important to understand how the induced changes in band gap relate to shifts in the valence and/or conduction band.
In this poster, I will present recent findings regarding measurements of the electronic structure of various hybrid perovskites using photoelectron spectroscopy. Hereby, we cove the whole range of lead and tin based perovskite systems, therefore varying the halogens (Cl, Br, I) as well as cations (Cs, MA, FA). We investigate how the changes in composition influence the ionization energy as well as electron affinity and compare these results with DFT calculations.