Extended Data Fig. 3: Characterization of perovskite/BPA core/shell interface.
From: Ultra-bright, efficient and stable perovskite light-emitting diodes
a, High-resolution HAADF-STEM image of single perovskite grain formed during in situ core/shell synthesis process. b, c, Atomic-scale HAADF-STEM (b) and ABF-STEM (c) images of the boxed area denoted in a. d,e, Magnified HAADF-STEM (d) and ABF-STEM (e) images of the boxed area shown in b and c to indicate the positions of EELS acquisition. f, EEL spectra acquired at the atomic positions labelled A, B, and C in d, e. g, EEL spectrum in the energy-loss range of the N-K and O-K edges acquired at the position labelled C. The O-K peak indicates the presence of BPA shells, but N-K peak is simply a background signal from the silicon nitride TEM window grid.
