Cryogenic 4D-STEM analysis of an amorphous-crystalline polymer blend: Combined nanocrystalline and amorphous phase mapping

Donohue, Jennifer; Bustillo, Karen C.; Savitzky, Benjamin H.; Jones, Mary Ann; Meyers, Gregory F.; Ophus, Colin; Minor, Andrew M.

doi:10.1016/j.isci.2022.103882

Cited by 13 publications

(13 citation statements)

References 61 publications

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“…However, it did not alter peak positions (see Figure S10, Supporting Information). [ 52 ] The atomic nearest‐neighbor distances were analyzed by fitting a Gaussian function to the 1st PDF peak. A slight gradual background change over micrometers could be observed in the nearest‐neighbor map following the changes in the sample thickness map (Figure S4b, Supporting Information).…”

Section: Methodsmentioning

confidence: 99%

Direct Observation of Quadrupolar Strain Fields forming a Shear Band in Metallic Glasses

et al. 2023

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For decades, scanning/transmission electron microscopy (S/TEM) techniques have been employed to analyze shear bands in metallic glasses and understand their formation in order to improve the mechanical properties of metallic glasses. However, due to a lack of direct information in reciprocal space, conventional S/TEM cannot characterize the local strain and atomic structure of amorphous materials, which are key to describe the deformation of glasses. For this work, 4-dimensional-STEM (4D-STEM) is applied to map and directly correlate the local strain and the atomic structure at the nanometer scale in deformed metallic glasses. Residual strain fields are observed with quadrupolar symmetry concentrated at dilated Eshelby inclusions. The strain fields percolate in a vortex-like manner building up the shear band. This provides a new understanding of the formation of shear bands in metallic glass.

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Section: Methodsmentioning

confidence: 99%

Direct Observation of Quadrupolar Strain Fields forming a Shear Band in Metallic Glasses

et al. 2023

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“…The low-dose high-resolution acquisition configuration demonstrated here likewise establishes a route to wider application of STEM-ePDF to beam sensitive organic and hybrid materials at room temperature. Previously, ePDF has been applied to the analysis of organic semiconductor blends by Mu et al 54 at 860 e − Å −2 and a crystalline-amorphous blend at cryogenic temperatures by Donohue et al 53 at 60 e − Å −2 , compared to our 10 e − Å −2 . Furthermore, we were able to achieve high spatial resolution (5 nm) at such low doses by the application of PCA and ICA to extract low-noise component signals.…”

Section: (D)mentioning

confidence: 99%

“…SED has been used to analyze a variety of organic structures using very low doses, such as crystalline MOFs, 23,50 protein structures, 51 and organic semiconductors. 52 SED has also been combined with ePDF analysis to provide structural data from amorphous-crystalline composites 53 amorphous organic semiconductors 54 and metallic glasses 55 with a few to 10 nm spatial resolution. However, such studies have so far been unable to work at both low dose (<50 e − Å −2 ) and high (<10 nm) spatial resolution.…”

Section: Introductionmentioning

confidence: 99%

Mapping short-range order at the nanoscale in metal–organic framework and inorganic glass composites

et al. 2022

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“…those used for pharmaceutical applications [42]), and information can be obtained from spatially averaged diffraction experiments, where the spatially resolved structure is of less importance. 4D-STEM experiments with small semi-convergence angles α (nano-beam diffraction or NBD) have recently demonstrated the retrieval of rich structural information from soft materials [39,43,44], including organic crystals with large unit cells and corresponding diffracted signals at small scattering angles and also analysis of amorphous materials [45]. Furthermore, we have recently introduced 4D-scanning confocal electron diffraction (4D-SCED) as another 4D-STEM modality that optimizes dose efficiency and angular resolution [16].…”

Section: Dose-efficient Diffraction Imaging Of Nano-crystalline Struc...mentioning

confidence: 99%

Using a fast hybrid pixel detector for dose-efficient diffraction imaging beam-sensitive organic molecular thin films

Wu,

Stroppa,

Pelz

et al. 2023

J. Phys. Mater.

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We discuss the benefits and showcase the applications of using a fast, hybrid-pixel detector (HPD) for 4D-STEM experiments and emphasize that in diffraction imaging the structure of molecular nano-crystallites in organic solar cell thin films with a dose-efficient modality 4D-scanning confocal electron diffraction (4D-SCED). With 4D-SCED, spot diffraction patterns form from an interaction area of a few nm while the electron beam rasters over the sample, resulting in high dose effectiveness yet highly demanding on the detector in frame speed, sensitivity, and single-pixel count rate. We compare the datasets acquired with 4D-SCED using a fast HPD with those using state-of-the-art complementary metal-oxide-semiconductor (CMOS) cameras to map the in-plane orientation of π-stacking nano-crystallites of small molecule DRCN5T in a blend of DRCN5T: PC71BM after solvent vapor annealing. The high-speed CMOS camera, using a scintillator optimized for low doses, showed impressive results for electron sensitivity and low noise. However, the limited speed restricted practical experimental conditions and caused unintended damage to small and weak nano-crystallites. The fast HPD, with a speed three orders of magnitude higher, allows a much higher probe current yet a lower total dose on the sample, and more scan points cover a large field of view in less time. A lot more faint diffraction signals that correspond to just a few electron events are detected. The improved performance of direct electron detectors opens more possibilities to enhance the characterization of beam-sensitive materials using 4D-STEM techniques.

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Cryogenic 4D-STEM analysis of an amorphous-crystalline polymer blend: Combined nanocrystalline and amorphous phase mapping

Cited by 13 publications

References 61 publications

Direct Observation of Quadrupolar Strain Fields forming a Shear Band in Metallic Glasses

Direct Observation of Quadrupolar Strain Fields forming a Shear Band in Metallic Glasses

Mapping short-range order at the nanoscale in metal–organic framework and inorganic glass composites

Using a fast hybrid pixel detector for dose-efficient diffraction imaging beam-sensitive organic molecular thin films

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