Eric Chason | Searcharxiv

arXiv2023

Elastic Modulus of Polycrystalline Halide Perovskite Thin Films on Substrates

Using an innovative combination of multi-beam-optical stress-sensor (MOSS) curvature and X-ray diffraction (XRD) techniques, the Young's modulus (E) of polycrystalline MAPbI3 metal-halide perovskite (MHP) thin films attached to Si substrates is estimated to be 10.2 +/- 3.4 GPa. This is comparable to the E of corresponding MAPbI3 single-crystals. This generic method could be applied to other systems to estimate hard-to-measure E of thin films.

cond-mat.mtrl-sci↗

arXiv2016

Experimental calibration of a Cahn-Hilliard phase-field model for phase transformations in Li-Sn electrodes

Experiments, numerical simulations, and analytical calculations are used to calibrate a diffuse-interface Cahn-Hilliard model of Li-Sn thin film electrodes that experience a transformation from Sn to Li2Sn5. It is shown that a concentration-gradient dependent mobility can be used in the Cahn-Hilliard equation to give the interface a finite mobility and capture its nonequilibrium behavior. Comparing experiments and simulations, the free-energy of Li-Sn, diffusivity of Li in Sn and Li2Sn5, the exchange current density for the surface reaction, and the mobility of the Sn/Li2Sn5 interface are extracted. The implications of finite interface mobility for practical battery electrodes are discussed.

cond-mat.mtrl-sci↗