stem eels spectrum imaging  (Gatan Inc)

Journal: ACS Nano

Article Title: Ligand-Engineered Methylammonium Lead Bromide Nanoplatelets: Single-Photon Emission and Strong Light-Matter Coupling

doi: 10.1021/acsnano.6c01048

Figure Lengend Snippet: Assemblies of MAPbBr 3 NPLs. (a) DF-STEM and (b) HAADF-STEM images of lecithin-capped MAPbBr 3 NPL assemblies demonstrating sub-μm domain dimensions and face-to-face NPL stacking, respectively. (c) High-angle region of the XRD pattern of MAPbBr 3 NPL drop-cast film (dark blue line) displaying peaks at q > 1.0 Å –1 , attributed to the MAPbBr 3 phase, and the diffraction peaks corresponding to the NPL stacking (q = 2πn/d with d = 49 Å and n = 2–4, 6–9, marked with an asterisk). The n = 5 peak is absent as it is structurally too weak to be detected ( Figure S8 ). Black vertical lines denote reference reflections for single-crystal MAPbBr 3 ( Pm3̅m , ICSD 252415). (d) Low-angle region of the XRD pattern of MAPbBr 3 NPL drop-cast film (dark blue line), revealing the first peak ( n = 1, marked with an asterisk) corresponding to the NPL periodicity of 4.8 nm, depicted in (b). (e) 2D low-angle region of GIWAXS pattern showing the rings corresponding to the NPL periodicity. (f) The polar plot of the 2D GIWAXS pattern in the q < 1.4 Å –1 region. The rings corresponding to the periodic arrangement of NPL are transformed into vertical lines in the polar plot; the n = 5 reflection is absent. The ψ = ± 90° peaks at q = 1.06 Å –1 belong to the MAPbBr 3 phase (100 reflection in the cubic notation). (g) Azimuthally integrated 1D pattern in the q > 0.2 Å –1 region (dark blue line), revealing Bragg peaks for the MAPbBr 3 phase (black vertical lines) and the diffraction peaks corresponding to NPL stacking (marked with an asterisk).

Article Snippet: TEM and STEM images were collected with a JEOL JEM 2200FS electron microscope operating at an accelerating voltage of 200 kV.

Techniques: Transformation Assay