Lead halide perovskites (LHPs) have recently emerged in a wide variety of optoelectronic applications such as solar cells, light-emitting diodes, lasers and photodetectors thanks to their exceptional electrical properties. Ferroic domain textures have been observed in organic-inorganic hybrid LHPs and investigated in the context of ferroelasticity. Despite these efforts, much remain unknown about ferroelasticity in LHPs and how it affects the chemical activity and optoelectronic properties of LHPs. A characteristic feature of a ferroelastic material is that it has coherent and switchable twin domains. Spontaneous strain forms across the phase transition which can be seen as microscopic stripe domains under polarized light microscopy. In this work, we directly visualize multiple domain wall switching in MAPbBr3 and CsPbBr3 through consecutive phase transitions3 thus proving a general ferroelasticity across the organic/inorganic boundary. Surprisingly the domain textures were directly visualized using non-polarized light microscopy. To directly verify ferroelasticity, stress was applied to observe switching of domain structures. Techniques like wide-field imaging, photoluminescence, reflectance and X-Ray diffraction (XRD) were used to probe structural and optical properties. New fundamental understanding of ferroelasticity in LHPs advances material engineering and optoelectronic applications.

Direct visualization of general ferroelasticity across hybrid and inorganic lead halide perovskites

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.