Structural Characterization of Amorphous and Nanocrystalline Materials Using Electron Diffraction

The electron diffraction-based pair distribution function (ePDF) has rapidly established itself as an experimental technique for quantitatively elucidating short-range order and medium-range order in amorphous and nanocrystalline materials. This review systematically summarizes the physical significance of ePDF, data acquisition and correction, scanning transmission electron microscopy-based local ePDF, and hyperspectral analysis approaches such as principal component analysis, independent component analysis and non-negative matrix factorization. Applications to metallic glasses, organic composites, and battery materials are highlighted. In addition, strategies to improve data reliability including multiple scattering correction and quantification, software developments, and recent advances such as Simple ePDF and quantitative ePDF, are discussed, along with future challenges.