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Diversified transformation paths of all-inorganic halide perovskites under pressure

June 23, 2021 , 13:00 14:00

Speaker: Prof. Marek Szafrański
Affiliation: Faculty of Physics, Adam Mickiewicz Univeristy in Poznań Poland
Link to MSTeams meeting

The discovery of spectacular photovoltaic properties of organic-inorganic hybrid perovskites has actuated intensive studies on these materials. Although the optical and electronic parameters of halide perovskites are excellent, their practical application is still hampered by long-term stability problems related to the resistance to atmospheric conditions such as humidity, temperature and UV illumination. These problems can be partly solved by the application of all-inorganic analogues of hybrid perovskites, which are characterized by high photovoltaic and optoelectronic performance associated with good operational stability. This presentation is aimed to show our recent high-pressure results obtained for all-inorganic perovskites CsPbX3 (where X = Cl, Br). These crystals undergo various types of pressure-induced transformations, including reversible phase transitions, irreversible chemical reactions reducing the dimensionality of PbX6 frameworks, and amorphization. The transformation routs depend on the mode of the applied stress and are related to the kinetics of transitions to the stable phases. The slow-kinetics transformations in a moderate pressure range of technological importance, between 0.5 and 1.5 GPa, can require days or even weeks, depending on the sample quality and external stimuli. The pressure-induced narrowing and widening of energy gaps has been explained by the mechanism combining Pb-X bond lengths and PbX6 octahedra tilts with the electronic structure of the crystals.

Seminar language: English
Chairman: Prof. Sławomir Breiter