Probing Ion Migration Dynamics at Liquid-Like Interphase Boundaries in Solid-State CsPbI3 Perovskite

Bio: Jeffrey Cheung is a 4th year PhD student working in the Clean Energy Lab group under Professor Alex Voznyy. His research focuses on studying the dynamics and properties at solid-state phase transformation boundaries.

Abstract: Enhancing the stability of solid-state materials for next-generation electronics and energy storage requires a deeper understanding of the dynamic structural transformations within solid matter. One such material, cesium lead iodide perovskite (CsPbI3), is widely used in optoelectronic devices and detectors. Specifically, CsPbI3 undergoes a reconstructive transformation between the non-perovskite ẟ-phase and the perovskite α-phase via thermal activation. While the thermodynamic landscape of this transition is well-documented, the kinetics governing interphase boundary migration remain obscure. Resolving atomic transport dynamics and extracting properties at these phase boundaries is beneficial for the engineering and discovery of novel materials.

In this work, we hypothesize that ion migration is enhanced at the solid-to-solid phase transformation interphase due to a transient rearrangement process. As a proof-of-concept, we simulated ion migration at these phase transformation boundaries using molecular dynamics. Experimentally, we explored a variety of temperature-dependent solid-state techniques, including solid-state impedance spectroscopy and powder X-ray diffraction, to resolve the dynamic changes in conductivity and structural behavior. Our combined computational and experimental approaches highlighted the involved complexity in resolving phase transformation of solid-state materials, motivating spatial approaches to probe diffusion properties at solid-state interphases.

Zoom Link: https://utoronto.zoom.us/j/84889438656
Meeting ID: 848 8943 8656
Passcode: pchemrocks

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