Diversified transformation paths of all-inorganic halide perovskites under pressure

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

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