Diffraction imaging of nanocrystalline structures in organic semiconductor molecular thin films

Panova, Ouliana; Ophus, Colin; Takacs, Christopher J.; Bustillo, Karen C.; Balhorn, Luke; Salleo, Alberto; Balsara, Nitash P.; Minor, Andrew M.

doi:10.1038/s41563-019-0387-3

Cited by 131 publications

(132 citation statements)

References 39 publications

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“…X-ray nanoimaging and transmission electron microscopy (TEM) methods are poorly suited to molecular materials due to low-scattering cross-sections and low damage threshold. Even specialized low-dose imaging has yet been unable to distinguish adjacent amorphous and crystalline phases (52). While previous studies using TEM and far-field spectroscopy had assigned broad spectral features to isolated RuOEP with the P3HT matrix (31), we instead observed, using vibrational exciton nanospectroscopy, the coexistence of amorphous and crystalline phases, with domains as small as a few molecules.…”

Section: Discussioncontrasting

confidence: 57%

Vibrational exciton nanoimaging of phases and domains in porphyrin nanocrystals

Muller

Gray

Zhou

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Much of the electronic transport, photophysical, or biological functions of molecular materials emerge from intermolecular interactions and associated nanoscale structure and morphology. However, competing phases, defects, and disorder give rise to confinement and many-body localization of the associated wavefunction, disturbing the performance of the material. Here, we employ vibrational excitons as a sensitive local probe of intermolecular coupling in hyperspectral infrared scattering scanning near-field optical microscopy (IR s-SNOM) with complementary small-angle X-ray scattering to map multiscale structure from molecular coupling to long-range order. In the model organic electronic material octaethyl porphyrin ruthenium(II) carbonyl (RuOEP), we observe the evolution of competing ordered and disordered phases, in nucleation, growth, and ripening of porphyrin nanocrystals. From measurement of vibrational exciton delocalization, we identify coexistence of ordered and disordered phases in RuOEP that extend down to the molecular scale. Even when reaching a high degree of macroscopic crystallinity, identify significant local disorder with correlation lengths of only a few nanometers. This minimally invasive approach of vibrational exciton nanospectroscopy and -imaging is generally applicable to provide the molecular-level insight into photoresponse and energy transport in organic photovoltaics, electronics, or proteins. infrared spectroscopy | molecular vibrations | scattering-scanning near-field optical microscopy (s-SNOM) | vibrational exciton | molecular energy transport

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Section: Discussioncontrasting

confidence: 57%

Vibrational exciton nanoimaging of phases and domains in porphyrin nanocrystals

Muller

Gray

Zhou

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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“…SED has recently been applied to characterize correlated defects, for example, using the symmetry within individual convergent beam diffraction disks to map domains in relaxor ferroelectrics 31 and superlattice reflections as signatures of correlated disorder in meteorites. 32 Further, SED has been applied to beam sensitive materials revealing crystallinity in organic molecular crystals 33 , polymers 34 and MOFs. 35,36 Here, we apply SED to directly visualize nanoscale defect domains in UiO-66(Hf).…”

Section: Sed Is a Four-dimensional Scanning Transmission Electron Micmentioning

confidence: 99%

Direct Imaging of Correlated Defect Nanodomains in a Metal-Organic Framework

Johnstone

Firth²,

Grey³

et al. 2020

Preprint

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<p>Defect engineering can enhance key properties of metal-organic frameworks (MOFs). Tailoring the distribution of defects, for example in correlated nanodomains, requires characterization across length scales. However, a critical nanoscale characterization gap has emerged between the bulk diffraction techniques used to detect defect nanodomains and the sub-nanometre imaging used to observe individual defects. Here, we demonstrate that the emerging technique of scanning electron diffraction (SED) can bridge this gap. We directly image defect nanodomains in the MOF UiO-66(Hf) over an area of ca. 1 000 nm and with a spatial resolution ca. 5 nm to reveal domain morphology and distribution. Based on these observations, we suggest possible crystal growth processes underpinning synthetic control of defect nanodomains. We also identify likely dislocations and small angle grain boundaries, illustrating that SED could be a key technique in developing the potential for engineering the distribution of defects, or “microstructure”, in functional MOF design.</p>

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“…We are cu quantify the increase in rec achieved for beam-sensitive s sented in this paper, we are co may enable 3D reconstruction of magnetic fields, 57-59 atomic potentials, 57 or orientational order in molecular liquid crystals and organic semiconductors. 58 The ability of pixelated detectors to record a full diffraction pattern at every probe position (leading to a five-dimensional data set) means strain fields, local crystalline order, and topological defects such as dislocations can be far more easily reconstructed in three dimensions, without requiring prior knowledge of where to sample in reciprocal space.…”

Section: Going Forwardmentioning

confidence: 99%

Electron tomography for functional nanomaterials

Hovden

Muller

2020

MRS Bull.

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This article was published in MRS Bulletin Volume 45, Issue 4 (Nanoscale TomographyUsing X-rays and Electrons) April 2020 , pp. 298-304 https://doi.org/10.1557/mrs.2020.87Modern nanomaterials contain complexity that spans all three dimensions-from multi-gate semiconductors to clean energy nanocatalysts to complex block copolymers. For nanoscale characterization, it has been a longstanding goal to observe and quantify the three-dimensional (3D) structure-not just surfaces, but the entire internal volume and the chemical arrangement.Electron tomography estimates the complete 3D structure of nanomaterials from a series of twodimensional projections taken across many viewing angles. Since its first introduction in 1968, electron tomography has progressed substantially in resolution, dose and chemical sensitivity. In particular, scanning transmission electron microscope tomography has greatly enhanced the study of 3D nanomaterials by providing quantifiable internal morphology and spectroscopic detection of elements. Combined with recent innovations in computational reconstruction algorithms and 3D visualization tools, scientists can interactively dissect volumetric representations and extract meaningful statistics of specimens. This article highlights the maturing field of electron tomography and the widening scientific applications that utilize 3D structural, chemical, and functional imaging at the nanometer and subnanometer length scales. Keywords: electron tomography, scanning transmission electron microscopy, transmission electron microscopy, electron energy loss spectroscopy MRS BulletinHovden and Muller/Apr20

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Diffraction imaging of nanocrystalline structures in organic semiconductor molecular thin films

Cited by 131 publications

References 39 publications

Vibrational exciton nanoimaging of phases and domains in porphyrin nanocrystals

Vibrational exciton nanoimaging of phases and domains in porphyrin nanocrystals

Direct Imaging of Correlated Defect Nanodomains in a Metal-Organic Framework

Electron tomography for functional nanomaterials

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